JP2009230438A - Reading apparatus, written information processing system, controller for reading apparatus, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the degradation of reading precision in a code image on a medium associated with a posture change of a reading apparatus with respect to the medium. <P>SOLUTION: A digital pen includes the first infrared LED 63a and the second infrared LED 63b for irradiating a printed document formed with the code image, with a light, a light emission control part 612 for selecting the LED lighting on when performing a writing operation onto the printed document by a user, an infrared CMOS 64 for receiving a reflected light from the printed document irradiated with the light from the selected LED, and an image processing part 614 for image-processing photoreception results by the infrared CMOS 64, to obtain the code image, for decoding the obtained code image, to find identification information and positional information, for finding a distortion of the obtaianed code image, and for determining a tilt direction the digital pen with respect to the printed document, based on the distortion, and the light emission control part 612 switches the lighting-on infrared LED, based on the obtaiened tilt direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reading device, a writing information processing system, a control device for the reading device, and a program.

  2. Description of the Related Art In recent years, for example, a pen-type input device used by a user in hand has attracted attention as an input device for a computer device. This type of pen-type input device includes a reading device that reads an image formed on a medium in addition to a recording device as a so-called pen that writes on a medium. Such a reading apparatus is realized by including a light source that irradiates light to a medium and a light receiving unit that receives reflected light from the medium (see, for example, Patent Document 1).

Special table 2004-527853 gazette

  By the way, in the pen-type input device, depending on the orientation of the reading device with respect to the medium, specularly reflected light that is irradiated from the light source and reflected by the medium enters the light receiving unit, and as a result, the reading accuracy of the code image is lowered. There was a thing.

  An object of the present invention is to suppress a decrease in reading accuracy of a code image accompanying a change in posture of a reading device with respect to a medium.

According to the first aspect of the present invention, a plurality of irradiation means for irradiating light to the medium on which the code image is formed, and one of the plurality of irradiation means is turned on, and the irradiation is performed. A reading unit that reads the code image from the medium irradiated with light, a determination unit that determines an inclination direction of the apparatus with respect to the medium from an inclination of the code image read by the reading unit, and the determination And a switching unit that switches an irradiation unit to be turned on from the plurality of irradiation units according to the tilt direction determined by the unit.
According to a second aspect of the present invention, the plurality of irradiation units include a first irradiation unit and a second irradiation unit that irradiate light toward a reading position of the medium by the reading unit, and the first irradiation unit. When specularly reflected light that has been irradiated by the irradiation unit and reflected by the medium is incident on the reading unit, the specularly reflected light that has been irradiated by the second irradiation unit and reflected by the medium is incident on the reading unit. 2. The reading apparatus according to claim 1, wherein an irradiation direction of light of each of the first irradiation unit and the second irradiation unit is set so that the first irradiation unit and the second irradiation unit are not.
According to a third aspect of the present invention, the plurality of irradiation means includes a first irradiation means and a second irradiation means for irradiating light toward a reading position of the medium by the reading means, and the first irradiation means. A first optical axis from the irradiation unit to the reading position and a second optical axis from the second irradiation unit to the reading position are a third optical axis from the reading position to the reading unit. The reading apparatus according to claim 1, wherein the reading apparatus has a symmetric positional relationship with respect to.
According to a fourth aspect of the present invention, the reading unit includes a light receiving sensor having a light receiving region that receives reflected light from the medium, and the determining unit is obtained by dividing the light receiving region into a plurality of regions. 4. The reading apparatus according to claim 1, wherein the number of code images acquired in each region is counted, and the inclination of the code image is obtained from the obtained count result for each region. 5. is there.
The invention according to claim 5 further includes acquisition means for acquiring predetermined information embedded in the code image from the code image read by the reading means. A reading device according to claim 1.
The invention according to claim 6 is the reading apparatus according to any one of claims 1 to 5, further comprising writing means for writing on the medium.

The invention according to claim 7 is read by the medium on which the code image is formed, the electronic writing instrument that reads the code image from the medium according to a writing operation on the medium by a user, and the electronic writing instrument. An information processing device that acquires information related to the code image and stores the writing content on the medium in association with the medium or an electronic document printed on the medium based on the acquired information, The writing instrument is lit by lighting a writing means for writing on the medium, a plurality of irradiation means for irradiating the medium with light, and any one of the plurality of irradiation means. Reading means for reading the code image from the medium irradiated with light by the irradiation means; and the information related to the code image read by the reading means According to the inclination direction determined by the determination means, the determination means for determining the inclination direction of the apparatus with respect to the medium from the inclination of the code image read by the reading means, A writing information processing system having switching means for switching an irradiation means to be lit among a plurality of irradiation means.
According to an eighth aspect of the present invention, the code image formed on the medium includes unit code pattern images formed by arranging a certain number of unit images in a predetermined section in two directions orthogonal to each other. In the electronic writing instrument, the reading unit includes a light receiving sensor having a light receiving region that receives reflected light from the medium, and the determination unit is obtained by dividing the light receiving region into a plurality of regions. 8. The writing information processing system according to claim 7, wherein the number of unit images acquired in each of the obtained areas is counted, and the inclination of the code image is obtained from the obtained counting result for each area.
According to a ninth aspect of the present invention, the electronic writing instrument obtains identification information of the medium or position information in the medium as the information related to the code image from the code image read by the reading unit. The information processing apparatus further includes an acquisition unit configured to output to the transmission unit, and performs a process of reading an electronic document associated with the identification information and superimposing a writing locus corresponding to the position information on the electronic document. The handwritten information processing system according to claim 7 or 8, wherein

  According to a tenth aspect of the present invention, light is emitted from a lighting instruction unit that turns on one of a plurality of light sources that emits light to a medium on which a code image is formed, and the light source that is lit. Read instruction means for reading the code image from the medium, determination means for determining the inclination direction of the reading device with respect to the medium from the inclination of the read code image, and the inclination direction determined by the determination means And a switching instruction means for outputting an instruction to switch the light source to be turned on from among the plurality of light sources to the lighting instruction means.

According to an eleventh aspect of the present invention, a computer has a function of lighting any one of a plurality of light sources that irradiates light onto a medium on which a code image is formed, and light is emitted from the light source that is lit. The function of reading the code image from the irradiated medium, the function of determining the tilt direction of the apparatus with respect to the medium from the tilt of the read code image, and the plurality of the plurality according to the determined tilt direction This is a program for realizing a function of switching a light source to be turned on from among the light sources.
The invention according to claim 12 is the program according to claim 11, further causing the computer to realize a function of acquiring predetermined information embedded in the code image from the read code image. .

According to the first aspect of the present invention, it is possible to suppress a decrease in the reading accuracy of the code image due to a change in the posture of the reading device with respect to the medium.
According to the invention described in claim 2, when switching from the first irradiation means to the second irradiation means and when switching from the second irradiation means to the first irradiation means, the medium The direction of the specularly reflected light from can be shifted from the reading means.
According to the third aspect of the present invention, when switching from the first irradiation means to the second irradiation means and when switching from the second irradiation means to the first irradiation means, the medium The direction of the specularly reflected light from can be shifted from the reading means.
According to the fourth aspect of the present invention, the tilt direction of the reading device with respect to the medium can be accurately grasped from the code image.
According to the fifth aspect of the present invention, information can be acquired from the code image.
According to the sixth aspect of the present invention, it is possible to acquire a writing trajectory for the medium using the code image reading result.
According to the seventh aspect of the present invention, it is possible to suppress a decrease in reading accuracy of the code image accompanying a change in the posture of the electronic writing instrument with respect to the medium.
According to invention of Claim 8, the inclination direction of the electronic writing instrument with respect to a medium can be grasped | ascertained correctly from a code | cord | chord image.
According to the invention described in claim 9, it is possible to improve the accuracy of the writing trajectory when the writing trajectory is added to the electronic document.
According to the tenth aspect of the present invention, it is possible to suppress a decrease in the reading accuracy of the code image accompanying a change in the posture of the reading device with respect to the medium.
According to the eleventh aspect of the present invention, it is possible to suppress a decrease in the reading accuracy of the code image accompanying a change in the posture of the reading device with respect to the medium.
According to the twelfth aspect of the present invention, information can be acquired from the code image.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
First, the overall configuration of the handwriting information management system in the present embodiment will be described.
FIG. 1 is a diagram showing an example of the configuration of the handwriting information management system of the present embodiment. This handwriting information management system is configured by connecting a terminal device 10, a document server 20, an identification information server 30, an image forming device 40, and a terminal device 50 to a network 80. A digital pen 60 is connected to the terminal device 50 via a communication device 70.

The terminal device 10 is used to output an electronic document print request. As such a terminal device 10, for example, a personal computer (PC) is used.
The document server 20 stores an electronic document. When there is a print request for the electronic document, the document server 20 instructs the formation of a superimposed image in which an image of the electronic document, that is, a document image and a code pattern image described later are superimposed. As such a document server 20, for example, a general-purpose server computer is used.
The identification information server 30 as an example of the information processing apparatus issues identification information to be given to the medium. The identification information server 30 manages the issued identification information in association with the electronic document printed on the medium. In the present embodiment, the identification information server 30 also has a function of specifying an electronic document associated with the identification information. As such an identification information server 30, for example, a general-purpose server computer is used.

The image forming apparatus 40 forms a superimposed image including a document image and a code pattern image on a medium and outputs it as a printed document 90. Here, an electrophotographic system is used as an image forming system in the image forming apparatus 40, but any other system such as an ink jet system may be employed. In this embodiment, the document image is formed using cyan, magenta, and yellow toners, and the code pattern image is formed using black toner. This is because the black toner has more infrared light absorption than the cyan, magenta, and yellow toners, and the digital pen 60 can read the code pattern image. However, the present invention is not limited to this, and the document image may be formed using cyan, magenta, and yellow toners, and the code pattern image may be formed using special toner. Here, examples of the special toner include invisible toner having a maximum absorption rate of 7% or less in the visible light region (400 to 700 nm) and an absorption rate of 3% or more in the near infrared region (800 to 1000 nm). . Here, “visible” and “invisible” are not related to whether or not they can be recognized visually. Specifically, “visible” and “invisible” are distinguished based on whether or not an image formed on a printed medium can be recognized by the presence or absence of color development due to absorption of a specific wavelength in the visible light region. . Also, “invisible” includes those that have some color developability due to absorption of a specific wavelength in the visible light region but are difficult to recognize with human eyes.
A digital pen 60 as an example of a reading device or an electronic writing instrument is a reading device having a function of recording (writing) characters and figures on a printed document 90. In the present embodiment, the digital pen 60 also has a function of transmitting information acquired from the code pattern image formed on the print document 90 to the terminal device 50. For example, a personal computer is used as the terminal device 50.

Next, the operation in this handwriting information management system will be described.
First, an operation when outputting the print document 90 in the handwriting information management system will be described.
When a print request for an electronic document is made from the terminal device 10, the document server 20 receives the print request from the terminal device 10 and instructs the image forming apparatus 40 to print the electronic document that is the target of the print request. As a result, the image forming apparatus 40 prints the document image of the electronic document on a medium such as paper. At this time, the image forming apparatus 40 prints a code pattern image on the medium in addition to the document image. Document 90 is output.
Here, the code pattern image is an image of the identification code and position code obtained by encoding the identification information and position information. The identification information is information for uniquely identifying a medium, and is issued by the identification information server 30 in the present embodiment. The position information is information for specifying the coordinate position on the medium, and is generated by the document server 20 in the present embodiment. Note that the identification information may uniquely identify a document image printed on a recording medium, for example, in addition to uniquely identifying a medium.

Next, an operation when writing is performed on the print document 90 using the digital pen 60 will be described.
When the user writes with the digital pen 60 on the printed document 90 on which the document image and the code pattern image are printed, the digital pen 60 writes handwritten information (handwriting information) based on the position information included in the code pattern image. Generate. At the same time, the digital pen 60 recognizes the identification information included in the code pattern image. The recognized identification information and the generated handwriting information are sent to the document server 20 via the terminal device 50. The document server 20 that has received the identification information and the handwriting information specifies the electronic document corresponding to the print document 90 based on the identification information, and stores the specified electronic document and the handwriting information in association with each other.

In this specification, electronic data that is the basis of an image recorded on a medium is expressed as “electronic document”. However, this does not mean only data obtained by digitizing a “document” including text. For example, "electronic document" including image data such as pictures, photos, figures (regardless of raster data or vector data), data recorded by database management software or spreadsheet software, and other printable electronic data It is said.
In the present specification, the “medium” may be any material as long as it can print an image. A typical example is paper, but it may be a plastic sheet such as an OHP sheet or a metal plate.

Next, a code pattern image as an example of a code image used in the present embodiment will be described in detail.
The code pattern image is an image of a code obtained by encoding predetermined information. In this example, both the identification information and the position information are included, but only one of the information is included. For example, it may include other information such as a synchronization code described later. In the present embodiment, a code block that is a constituent unit of information included in a code pattern image is configured by a plurality of unit code patterns. The unit code pattern is the minimum unit of information embedding, and is represented by forming a unit image at a predetermined position. Here, a unit image having any shape may be used. In the present embodiment, a dot image (hereinafter simply referred to as “dot”) is used as an example of a unit image, but an image having another shape such as a hatched pattern may be used.

(Unit code pattern)
FIG. 2 is an explanatory diagram showing an example of a unit code pattern constituting a code pattern image. In this example, as an example of a predetermined section, two places are selected from the places where a total of nine dots in three places in the vertical direction (hereinafter referred to as 3 × 3 places) can be arranged, and the dots are arranged. To do. In this case, there are 36 dot arrangement combinations of unit code patterns (36 = ₉ C ₂ ) (where _m C _n = m! / {(Mn)! × n!}). When recording at a resolution of 600 dpi, one dot size (square size) in FIG. 2 is 2 pixels in the vertical direction and 2 pixels in the horizontal direction (hereinafter referred to as 2 × 2 pixels). Note that 2 × 2 pixels are rectangular with a side length of 84.6 μm in the calculation, but the recorded toner image has a circular shape of about φ100 μm. Accordingly, the unit code pattern is a rectangle (0.5076 × 0.5076 mm) having a side length of 0.5076 mm.

Of the 36 combinations, 4 (4 = 2 ² ) are used as synchronization codes for detecting a code block (described later) and detecting a rotation angle. At this time, in order to detect the rotation angle of the code block in units of 90 degrees, the four patterns are selected to be 90-degree rotationally symmetrical patterns. That is, if any one of the four patterns is embedded as a synchronization code at the time of image generation, the rotation angle of the code block (the code synchronized on the two-dimensional array) depends on the angle at which the synchronization code is detected at the time of decoding. Which direction of 0/90/180/270 degrees of the block is facing) can be determined and corrected.

The remaining 32 combinations (32 = 2 ⁵ ) of the 36 combinations are used for embedding information of 5 bits per unit code pattern. Here, FIG. 3 shows 36 dot arrangements that can be taken by the unit code pattern of FIG. 2 described above. In FIG. 3, a space between dots is omitted for simplification of display.
Note that the unit code pattern is not limited to the method of arranging dots in two of the nine locations as shown in the figure, and may be three or four. That is, it should be smaller than nine. For example, the combination of dot arrangement with the configuration of placing dots in positions 3 of 9 points becomes 84 kinds (84 = 9 _{C 3).} Further, the number of places where dots can be arranged is not limited to nine (3 × 3), but may be other numbers, for example, four (2 × 2) or 16 (4 × 4).

(Synchronous code combination)
FIG. 4 shows combinations of synchronization codes that can be selected from 36 dot arrangements that the unit code pattern of FIG. 2 can take. All the combinations shown in FIG. 4 are 90-degree rotationally symmetric. Any combination is used as four code patterns used for the synchronization code.

(Code block)
FIG. 5 shows an example of a code block for embedding a synchronization code, a position code, and an identification code. In this example, 5 × 5 unit code patterns shown in FIG. 2 are arranged to form a code block.

(Synchronous code)
The synchronization code shown in FIG. 4 is arranged at the upper left position of the code block shown in FIG. That is, one of the synchronization codes shown in FIGS. 4A to 4H is selected, and one selected from the four unit code patterns included in the selected synchronization code is arranged at the upper left of the code block. To do.

(Position code)
In the code block shown in FIG. 5, an X position code obtained by encoding information unique to the position in the X direction is arranged using four unit code patterns adjacent to the right side of the synchronization code. In the code block shown in FIG. 5, a Y position code obtained by encoding information unique to a position in the Y direction is arranged using four unit code patterns adjacent to the lower side of the synchronization code. Since each of the X position code and the Y position code uses four unit code patterns, each can store information of 20 bits (5 bits / unit code pattern × 4 pieces).
It should be noted that instead of using 32 types of information embedding patterns (32 = 2 ⁵ ) as position codes, only 16 types of patterns may be used. In this case, since the amount of information per unit code pattern is 4 bits (16 = 2 ⁴ ), the position code is 16 bits (4 bits / unit code pattern × 4 pieces) of information.

In this embodiment, M sequences are used as such position codes. For example, if a 12th-order M sequence is used, the sequence length of the M sequence is 4095 (= 2 ¹² −1). When 16 types of patterns are selected as the unit code pattern of the position code, information of 4 bits is stored in each unit code pattern, so that information of 16 bits (4 bits × 4 pieces) is stored in one code block. Accordingly, the M sequence having a sequence length of 4095 is divided and stored in 255 (= 4095 ÷ 16) code blocks. Since the width of one code block is 2.538 mm (= 0.5076 mm / unit code pattern width × 5), the length of 255 consecutive code blocks is 647.19 mm, and the length of 647.19 mm is the code. It becomes. That is, even A2 size (420 × 594 mm) paper is encoded.

  In addition, although the example which encoded the position with one M series was shown here, you may further increase the position encoded by concatenating several M series. For example, even when an 11th-order M series is used, A4 size paper is encoded by connecting four of them.

(Identification code)
In the code block shown in FIG. 5, identification codes are arranged in the remaining areas, that is, positions where no synchronization code or position code exists. Since 16 unit code patterns (4 × 4) are arranged in this area, 80 bits (5 bits / unit code pattern × 16) of information can be stored. Since the unit code pattern of the present embodiment is a multi-level code, errors that occur during reading and the like also occur in units of the unit code pattern. Accordingly, it is desirable that the error correction code be a system that can perform error correction in units of blocks. If an RS code, which is a known block error correction code system, is used for the identification code, the block length of the RS code becomes 5 bits, which is the information amount of the unit code pattern. In this case, the code length of the RS code is 16 blocks (= 80 bits / 5 bits / block). For example, if the correction capability of 3 blocks is provided, the information code length is 10 blocks (= 16 blocks−3 blocks × 2). It becomes. In this case, information of 50 bits (= 5 bits / block × 10 blocks) is embedded in the identification code area.

(Position code arrangement)
FIG. 6 shows an example in which position codes are arranged in a code pattern image. As described above, the M-sequence is divided into blocks each having 4 bits, which is the number of unit code pattern bits of the position code, and the divided blocks are sequentially arranged in a region sandwiched between synchronization codes. Although only the X position code is shown in FIG. 6, the same applies to the Y position code.
Since each code block has a synchronization code, the X position code and the Y position code are not arranged consecutively, and a synchronization code is arranged every four unit code patterns of the X position code and the Y position code. Will be.

(Distribution of identification codes)
FIG. 7 shows an example in which identification codes are arranged in a code pattern image. The identification code is arranged, for example, in the lower right quadrant of the synchronization code. Further, unlike the position code, the same information is always embedded in the identification code regardless of the image position.

Next, the digital pen 60 used for writing on the print document 90 and reading the writing locus will be described.
FIG. 8 is a diagram illustrating an outline of the configuration of the digital pen 60. The digital pen 60 detects the writing operation by the control unit 61 that controls the operation of the entire pen and the digital pen 60 by the pressure (writing pressure) applied to the pen tip 69 as an example of writing means, and puts the digital pen 60 into an operating state. The pen pressure detection switch 62 to be set, the first infrared LED (Light Emitting Diode) 63a that irradiates the medium with infrared light, and the second infrared LED 63b (in the following description, these are collectively referred to simply as the infrared LED 63). An infrared CMOS (Complementary Metal Oxide Semiconductor) 64 that captures an image is provided. Here, the first infrared LED 63a and the second infrared LED 63b are arranged so that their optical axes intersect with the print document 90 at different angles, details of which will be described later. The digital pen 60 includes an information memory 65 for storing identification information and position information, a communication circuit 66 as an example of a transmission unit for communicating with an external device (terminal device 50), and a battery for driving the digital pen 60. 67, a pen ID memory 68 for storing identification information (pen ID) of the digital pen 60 is further provided. These units are connected to the control unit 61.
In the digital pen 60 shown in FIG. 8, the direction from the near side to the far side in the figure is defined as the U direction. A direction from the right side to the left side in the figure is defined as a V direction. Furthermore, the direction from the lower side to the upper side in the figure is defined as the W direction. Here, the U direction, the V direction, and the W direction are orthogonal to each other. The U direction and the V direction correspond to the paper surface of the print document 90.

Next, the arrangement of the first infrared LED 63a and the second infrared LED 63b in the digital pen 60 will be described. Here, in the present embodiment, the first infrared LED 63a and the second infrared LED 63b function as a plurality of irradiation means, and the first infrared LED 63a serves as the first irradiation means. Each of the two infrared LEDs 63b functions as a second irradiation unit.
FIG. 9 is a view of the first infrared LED 63a, the second infrared LED 63b, and the infrared CMOS 64 constituting the digital pen 60 as seen from the IX direction shown in FIG. Therefore, in FIG. 9, the direction from the right side to the left side in the drawing is the U direction, and the direction from the back side to the near side in the drawing is the V direction.
In the present embodiment, the first infrared LED 63a and the second infrared LED 63b are respectively arranged so as to irradiate infrared light to the reading position R set in the vicinity of the writing position on the print document 90 by the pen tip 69. Is done. Further, the first infrared LED 63a and the second infrared LED 63b are symmetrical with respect to the light receiving axis (third optical axis) from the reading position R toward the infrared CMOS 64 when viewed from the IX direction shown in FIG. Be placed. Therefore, the first angle θ1 formed by the first illumination optical axis (first optical axis) from the first infrared LED 63a toward the reading position R and the light receiving axis and the second angle from the second infrared LED 63b toward the reading position R. The second angle θ2 formed by the second illumination optical axis (second optical axis) and the light receiving axis is equal. In the present embodiment, the sum of the first angle θ1 and the second angle θ2 is set to be 10 degrees or more. However, from the viewpoint of reducing the size of the digital pen 60, it is preferable that the sum of the first angle θ1 and the second angle θ2 is not large, for example, 30 degrees or less.
In the infrared CMOS 64, the infrared CMOS chip 641 (see FIG. 10) is arranged so as to face the reading position R. In the digital pen 60, an optical system (not shown) such as a lens is provided between the reading position R and the infrared CMOS 64.

FIG. 10 is a diagram illustrating an example of the configuration of the infrared CMOS 64 provided in the digital pen 60.
An infrared CMOS 64 as an example of a reading unit and a light receiving sensor includes an infrared CMOS chip 641, a lead frame 642 electrically connected to the infrared CMOS chip 641, and the infrared CMOS chip 641 and the lead frame 642. And a package part 643 integrated by a resin mold.
In the infrared CMOS chip 641, a large number of phototransistors are arranged in a matrix in the horizontal direction (referred to as the reference axis X direction) and the vertical direction (referred to as the reference axis Y direction). 8 and 9, in the state where the digital pen 60 is set upright in the W direction with respect to the print document 90, the X direction coincides with the U direction and the Y direction coincides with the V direction. ing. The infrared CMOS chip 641 outputs the received light data by a so-called XY address method that selects the output of the received light data for each cell. Further, since the infrared CMOS chip 641 adopts the XY address system, the light reception data of all the lines constituted by the cells, or the light reception data of half the lines thinned out every other line, for example, can be arbitrarily selected. Selected and output. In this case, if the output resolution of the former is 600 dpi, for example, the output resolution of the latter light reception data is half of the output resolution of the former, that is, 300 dpi.
In the following description, the left side (−X direction side) in the figure of the light receiving area, that is, the imaging area by the infrared CMOS chip 641 is referred to as the first imaging area S1, and the right side (X direction side) in the figure is the first. This will be referred to as a second imaging region S2. Here, the first imaging region S1 and the second imaging region S2 are divided into two along the Y direction, and both have the same area.
The infrared CMOS chip 641 is configured to read an image of an area of about 4 mm × about 4 mm at the reading position R (see FIG. 9). Therefore, the infrared CMOS chip 641 can simultaneously read about 64 (8 × 8) unit code patterns (0.5076 mm × 0.5076 mm) constituting the code pattern image formed on the print document 90. become.

FIG. 11 is a block diagram illustrating an example of the configuration of the control unit 61 provided in the digital pen 60.
The control unit 61 as an example of a control device of the reading device includes an overall control unit 611, a light emission control unit 612, a light reception control unit 613, and an image processing unit 614.
The overall control unit 611 as an example of a determination unit and a switching instruction unit controls the light emission control unit 612, the light reception control unit 613, and the image processing unit 614 based on a signal input from the writing pressure detection switch 62. The overall control unit 611 controls the light emission control unit 612 based on inclination information (described later) input from the image processing unit 614. The light emission control unit 612 as an example of the switching unit or the lighting instruction unit controls the light emission operation of the first infrared LED 63a and the second infrared LED 63b constituting the infrared LED 63 based on the instruction received from the overall control unit 611. . Specifically, control for selectively lighting one of the first infrared LED 63a and the second infrared LED 63b is executed. The light reception control unit 613 as an example of a reading instruction unit controls the light reception operation of the infrared CMOS 64 based on the instruction received from the overall control unit 611. The image processing unit 614 performs image processing on the received light data input from the infrared CMOS 64 based on the instruction received from the overall control unit 611, and outputs the obtained result to the communication circuit 66 and the overall control unit 611.

  FIG. 12 is a block diagram illustrating an example of the configuration of the image processing unit 614 of the control unit 61 illustrated in FIG. The image processing unit 614 includes an image acquisition unit 91, a noise removal unit 92, a binarization processing unit 93, a dot position detection unit 94, a reference dot pair detection unit 95, an angle detection unit 96, and a decoding unit. 97 and a pen tilt detection unit 98. Here, the reference dot pair detection unit 95 includes a proximity dot pair detection unit 95a and a dot pair selection unit 95b. The decoding unit 97 includes a synchronization unit 97a, a unit code pattern boundary detection unit 97b, a synchronization code detection unit 97c, an identification code detection unit 97d, an RS code decoding unit 97e, a position code detection unit 97f, A position code decoding unit 97g. Furthermore, the pen tilt detection unit 98 includes a dot distribution counting unit 98a and a pen tilt determination unit 98b.

The image acquisition unit 91 acquires a code pattern image read by the infrared CMOS 64 (see FIG. 8).
And the noise removal part 92 performs the process for removing the noise (The dispersion | variation in the sensitivity of infrared CMOS64 (imaging element) and the noise which generate | occur | produces with an electronic circuit) contained in the acquired code | cord pattern image. In addition, examples of the noise removal processing include sharpening processing such as blurring processing and unsharp masking.

  The binarization processing unit 93 cuts the code pattern image into a dot image and a background image by binarization processing. Then, the dot position detection unit 94 detects a dot formation position (hereinafter referred to as a dot position) in the code pattern image from the binarized individual dot images. However, since a binarized dot image may contain many noise components, it is determined whether the dot image is a dot image based on the area and shape of the binarized dot image before detecting the dot position. It is preferable to combine the filtering processes to be performed.

The proximity dot pair detection unit 95a in the reference dot pair detection unit 95 refers to the dot position detected by the dot position detection unit 94, for example, and forms a pair (proximity dot pair) with the closest dot position from each dot position. .
Further, the dot pair selection unit 95b selects a reference dot pair from among a plurality of generated adjacent dot pairs, for example. Here, the reference dot pair refers to a dot pair having a particularly short inter-dot distance among a plurality of adjacent dot pairs.
Then, the angle detector 96 detects the rotation angle of the code pattern image based on the selected reference dot pair, for example.

The decoding unit 97 as an example of an acquisition unit outputs predetermined information (identification information and position information) included in the code pattern image based on, for example, information such as the received dot position and rotation angle.
In the decoding unit 97, the synchronization unit 97a synchronizes the dot position on the two-dimensional array with reference to, for example, the detected dot position, the rotation angle, and the inter-dot distance of the reference dot pair. Here, “synchronize” means, for example, a process in which a position where a dot is present on a two-dimensional array is replaced with 1 and a position where a dot is not present is replaced with 0, etc. I mean.

Then, the unit code pattern boundary detection unit 97b detects the boundary of the unit code pattern constituting the code block from the dot positions synchronized on the two-dimensional array, for example. Specifically, for example, on the two-dimensional array output by the synchronization unit 97a, a rectangular separation position having the same size as the unit code pattern is appropriately moved, and the position where the number of dots included in the separation becomes equal is a unit. It is detected as the boundary position of the code pattern. Also, if the number of equalized dots is 2, a code pattern in which information is embedded with a unit code pattern of ₉ C ₂ , and if the number of dots is 3, information is embedded in a unit code pattern of ₉ C ₃ An information embedding method may be determined such as a code pattern.

  In addition, the synchronization code detection unit 97c detects the synchronization code with reference to the type of each unit code pattern detected from the two-dimensional array, for example. The synchronization code detector 97c detects the direction of the code pattern (in units of 90 degrees) and corrects it depending on which of the four types of synchronization codes (see FIG. 4) is detected.

Furthermore, the identification code detection unit 97d acquires the identification code from the code pattern whose angle is corrected with reference to the position of the synchronization code.
Furthermore, the RS code decoding unit 97e decodes the identification code detected using the same parameters (such as the number of blocks) used in the RS code encoding process, and outputs the obtained identification information.

On the other hand, the position code detection unit 97f acquires a position code from the code pattern whose angle is corrected with reference to the position of the synchronization code.
Then, the position code decoding unit 97g extracts the M series partial sequence from the position code acquired by the position code detection unit 97f, refers to the position of the detected partial sequence with respect to the M sequence used for image generation, The position offset information is corrected as position information (because the synchronization code is arranged between the position codes) and is output as position information.

For example, the pen tilt detection unit 98 outputs tilt information of the digital pen 60 with respect to the print document 90 based on the distribution of the dot positions detected by the dot position detection unit 94. As will be described later, the distribution of dot positions corresponds to the distortion of the code pattern image read by the infrared CMOS 64.
The dot distribution counting unit 98a refers to the dot position detected by the dot position detection unit 94, and whether each dot is imaged in the first imaging region S1 of the infrared CMOS chip 641 (see FIG. 10), or It is determined whether the image is captured in the second imaging region S2, and the count is performed for each.
The pen tilt determination unit 98b determines the tilt direction of the digital pen 60 with respect to the print document 90 from the count result of the dots captured in the first image capturing area S1 and the count result of the dots captured in the second image capturing area S2. The obtained tilt information is output.

  These functions are realized by cooperation between software and hardware resources. Specifically, a CPU (not shown) of the image processing unit 614 reads a program that realizes the function of each unit constituting the image processing unit 614 from a storage device such as an EEPROM into the information memory 65 (see FIG. 8) and executes the program. By doing so, these functions are realized. Further, the program and data stored in the EEPROM or the like may be loaded from a recording medium such as a CD or downloaded via a network such as the Internet.

  Next, various processes executed by the image processing unit 614 shown in FIG. 12 will be described in detail. Here, processing related to acquisition of identification information and position information will be described first, and then processing related to acquisition of tilt information of the digital pen 60 and accompanying lighting switching of the infrared LED 63 will be described.

[Processing related to acquisition of identification information and location information]
(Adjacent dot pair detection)
FIG. 13 is a diagram illustrating an example of a result of the proximity dot pair detection unit 95a (see FIG. 12) detecting the proximity dot pair among the processes executed by the reference dot pair detection unit 95 (see FIG. 12).
FIG. 13A shows an example of the dot position detected by the dot position detector 94 (see FIG. 12). The proximity dot pair detection unit 95a refers to each dot position as shown in FIG. 13A, and forms a pair (proximity dot pair) with a dot position closest to each dot position.
FIG. 13B shows an example of proximity dot pairs detected by the proximity dot pair detection unit 95a based on the dot positions as shown in FIG. Here, a pair of adjacent dots is represented by a line. In this case, when the dot B closest to a certain dot A forms a close dot pair with another dot C, the dot A does not form a close dot pair with any other dot.

(Selection of reference dot pair)
FIG. 14 is a diagram illustrating an example of a process in which the dot pair selection unit 95b (see FIG. 12) selects the reference dot pair among the processes executed by the reference dot pair detection unit 95 (see FIG. 12).
First, for example, the dot pair selection unit 95b creates a histogram based on the inter-dot distance for the proximity dot pair detected by the proximity dot pair detection unit 95a (see FIG. 12) (see FIG. 14A). Next, based on this histogram, the frequencies are accumulated in order from the shorter dot distance (see FIG. 14B). Then, the inter-dot distance at which the accumulated frequency becomes a predetermined value is set as a threshold value for the inter-dot distance of the reference dot pair (see FIG. 14C). The reference dot pair is obtained by excluding the dot pair having a large inter-dot distance using the threshold value thus determined.

The “predetermined value” is, for example, a value obtained by multiplying the number of all detected dots by a value determined by design according to the type of unit code pattern. For example, in the case of a unit code pattern of ₉ C ₂ (see FIG. 3), 12 dots are out of 36 patterns, and two dots are arranged adjacent to each other vertically and horizontally. 3. Therefore, a dot pair of a number obtained by multiplying half of the detected number of dots (to make a pair) by 1/3 should have two dots vertically and horizontally adjacent by design. Actually, since the unit code patterns are arranged adjacent to each other, the probability becomes a larger value. Here, the “predetermined value” is a value obtained by multiplying half of the number of dots detected in this way by the probability that two dots are adjacently arranged vertically and horizontally in the unit code pattern. For example, in the case of a ₉ C ₂ unit code pattern (see FIG. 3), the threshold corresponds to the inter-dot distance in the case where two dots are selectively arranged at adjacent reference positions in the vertical and horizontal directions. is doing. Therefore, in such a case, the orientations of the obtained reference dot pairs are in a positional relationship such that they are orthogonal to each other.

(Detection of rotation angle of code pattern image)
FIG. 15 shows an example of a result of the dot pair selection unit 95b (see FIG. 12) selecting the reference dot pair. An example in which the reference dot pair is arranged in a coordinate system including the reference axis X and the reference axis Y when detecting the rotation angle of the code pattern image is shown.

FIG. 15A shows an example of a result of selecting the reference dot pair from the adjacent dot pairs (see FIG. 13B) by the dot pair selection unit 95b (see FIG. 12). The pair is represented by a line.
In the example shown in this figure, the reference dot pairs are aggregated into a group of reference dot pairs facing the direction of the reference dot pair 90a and a group of reference dot pairs facing the direction of the reference dot pair 90b. That is, the reference dot pairs are divided into two groups, and these groups are paired in two directions. The direction of the group to which the reference dot pair 90a belongs and the direction of the group to which the reference dot pair 90b belongs make an almost constant angle (90 degrees).

Next, FIG. 15B and FIG. 15C will be described.
FIG. 15B shows a case where one dot of the reference dot pair is at the origin of the reference coordinate system composed of the reference axis X and the reference axis Y, and the other is in the first quadrant. FIG. 15C shows a case where the other of the reference dot pair is in the fourth quadrant. If the reference dot pair is positioned so that one dot of the reference dot pair is always at the origin of the reference coordinate system in this way, the inclination angle of the reference dot pair (one dot of the reference dot pair is connected to the other dot). The angle of the straight line from the reference axis X is limited to a range of −90 degrees to 90 degrees.
As shown in FIG. 10, the reference axis X constituting the reference coordinate system corresponds to the horizontal direction (X direction) of the infrared CMOS 64, and the reference axis Y is the vertical direction (Y direction) of the infrared CMOS 64. It corresponds to.

Based on the reference axis thus determined, the distance (ΔX) in the reference axis X direction and the distance (ΔY) in the reference axis Y direction between the dots constituting the reference dot pair are determined. In the case of FIG. 15B, both ΔX and ΔY are positive values, and in the case of FIG. 15C, ΔX is a positive value and ΔY is a negative value. When calculation is performed by applying a generally known trigonometric expression to ΔX and ΔY, the inclination angle of the reference dot pair is obtained.
If the obtained tilt angle is smaller than 0 degrees, 90 degrees is added to the tilt angle (see the right side of FIG. 15C). By this calculation, the tilt angle is compressed to a range of 0 degrees to 90 degrees.
Based on the plurality of inclination angles obtained in this way, an angle that minimizes the variation in the difference from each inclination angle is obtained as the rotation angle of the code pattern image. If the average rotation angle of the code pattern image is obtained by calculating the average value of each inclination angle, the angle of the reference dot pair that forms a pair in two directions is calculated as the inclination angle in one direction by this calculation. Will be.

  Further, for example, when a code pattern image is read with the digital pen 60, as will be described later, the image is distorted depending on the posture of the digital pen 60 with respect to the print document 90, and the reference dot pair on the detected code pattern image is 90 degrees orthogonal. There are cases where it is not in the direction. In such a case, if the average value is used independently for each of the two directions, the rotation angle of the code pattern image is detected from the distorted image.

(Specific example of virtual grid creation and synchronization processing by detecting rotation angle of code pattern image)
Next, a specific example of a virtual grid created based on the rotation angle of the code pattern image detected in the present embodiment and a synchronization process using the virtual grid will be described with reference to FIG.
FIG. 16A shows an example of a code pattern image. If the above-described processing is performed based on the reference dot pair selected from the dot position representing the code pattern image, the rotation angle of the code pattern image is acquired.

FIG. 16B shows an example of a virtual lattice. The direction of this virtual grid is estimated from the dot position. As is clear from the above description, when two dots are selected from the code pattern image, the distance between the two dots is the closest, for example, the two dots are adjacent in the 0 degree direction or the 90 degree direction, for example. It is a case where they are lined up. Therefore, the closest pair of dots (the reference dot pair) is detected from the plurality of detected dots, the rotation angle of the code pattern image is detected from the direction in which the pair of dots is directed, and the virtual lattice is detected. And the direction.
Here, the direction of the virtual lattice is the rotation angle of the code pattern image acquired from the code pattern image shown in FIG. The interval between the virtual lattices is the inter-dot distance of the reference dot pair.

  FIG. 16C shows the result of synchronizing the code pattern image (see FIG. 16A) using the virtual lattice illustrated in FIG. Here, a virtual grid is applied to the dots detected from the code pattern image, and the presence / absence of dots is inspected within the grid of each grid. A dimensional array is generated.

(Specific example of unit code pattern boundary detection)
FIG. 17 is a diagram illustrating an outline of processing performed by the unit code pattern boundary detection unit 97b (see FIG. 12).
Here, FIG. 17A shows a code pattern image of the present embodiment configured with a ₉ C ₂ unit code pattern (see FIG. 3). The object of boundary detection is actually a synchronized two-dimensional array composed of bit value 0 and bit value 1 as shown in FIG. 16 (c), but here it is easy to catch intuitively. A description will be given using a code pattern image with dots.

In order to acquire position information and identification information from a code pattern image as shown in FIG. 17A, it is necessary to first determine the boundary of the unit code pattern in order to specify the type of unit code pattern. FIG. 17B to FIG. 17D show the determination method.
That is, a virtual grid (see FIG. 17B) having a plurality of grids having the same grid size as the unit code pattern is prepared, and the virtual grid is scanned on the code pattern image. At this time, the number of dots included in each first mesh is counted, and the virtual grid is fixed at a position where the variation in the number of first dots entering the first mesh is the smallest. This fixed position becomes the boundary position of the unit code pattern.

For example, when a code pattern image is constructed using a unit code pattern of ₉ C ₂ (see FIG. 3), the number of dots entering each square is 2 at the correct virtual grid position shown in FIG. It becomes. However, in the case where the position of the correct virtual lattice is not as shown in FIGS. 17B and 17C, the number of dots entering each square varies in the range of 0 to 7.
For example, when the unit code pattern of ₉ C ₃ is used, the number of dots entering each square is 3 at the correct virtual lattice position, but the number varies when the position is not correct.

  After specifying the boundary position of the unit code pattern in this way, each unit code pattern is inspected to detect a synchronization code. Then, the rotation of the code pattern image is determined depending on whether any of the four types of synchronization codes is detected. Further, after correcting this rotation, the position code and the identification code are obtained therefrom.

[Acquisition of tilt information and light source switching]
(Overall processing flow)
FIG. 18 is a flowchart showing a flow of processing related to acquisition of tilt information of the digital pen 60 and switching of lighting of the infrared LED 63 (first infrared LED 63a and second infrared LED 63b) associated therewith.

In this process, first, the dot distribution counting unit 98a provided in the pen inclination detecting unit 98 acquires a plurality of dot positions detected by the dot position detecting unit 94 (step 101). Next, the dot distribution counting unit 98a determines whether each acquired dot position constituting the plurality of dot positions is imaged in the first imaging region S1 of the infrared CMOS chip 641 or the second imaging. It is determined whether the image is captured in the region S2, and the first dot number D1 that is the number of dots existing in the first image capturing region S1 and the second number that is the number of dots existing in the second image capturing region S2. Are counted (step 102), and the obtained first dot number D1 and second dot number D2 are output to the pen inclination determination unit 98b.
Subsequently, the pen inclination determination unit 98b determines whether or not the first dot number D1 is equal to or greater than the second dot number D2 (step 103), and the overall control unit 611 ( (See FIG. 11).

  When the first dot number D1 is equal to or greater than the second dot number D2 (D1 ≧ D2), the overall control unit 611 instructs the light emission control unit 612 to turn on the first infrared LED 63a. An instruction is output (step 104). In response to this, the light emission control unit 612 performs control to turn on the first infrared LED 63a. At this time, if the first infrared LED 63a has already been lit, the first infrared LED 63a is kept lit as it is. On the other hand, when the second infrared LED 63b is turned on, the second infrared LED 63b is turned off and the first infrared LED 63a is turned on.

  On the other hand, when the first dot number D1 is less than the second dot number D2 (D1 <D2), the overall control unit 611 instructs the light emission control unit 612 to turn on the second infrared LED 63b. An instruction is output (step 105). In response to this, the light emission control unit 612 performs control to turn on the second infrared LED 63b. At this time, if the second infrared LED 63b has already been lit, the second infrared LED 63b is kept lit as it is. On the other hand, when the first infrared LED 63a is turned on, the first infrared LED 63a is turned off and the second infrared LED 63b is turned on.

  Thereafter, it is determined whether or not the writing operation is finished (step 106). When the writing operation is finished, a series of processing is completed. On the other hand, when the writing operation is continued, the process returns to step 101 to continue the processing.

(Relationship between digital pen tilt and dot distribution)
FIG. 19 is a diagram illustrating the relationship between the inclination of the axis of the digital pen 60 with respect to the print document 90 and the code image data acquired by the infrared CMOS 64 provided in the digital pen 60 at each inclination. Here, FIG. 19B shows the case where the axis of the digital pen 60 is not inclined with respect to the print document 90, and FIG. 19A shows the axis of the digital pen 60 with respect to the print document 90 in the α direction (U direction). FIG. 19C illustrates the case where the axis of the digital pen 60 is inclined in the β direction (corresponding to the −U direction) with respect to the print document 90. 19A to 19C, the upper row shows the inclination of the axis of the digital pen 60 with respect to the print document 90, and the lower row shows the infrared CMOS 64 (specifically, the infrared CMOS chip 641) of the digital pen 60 at that time. The code image data acquired by () is shown respectively. Here, in order to simplify the description, it is assumed that the digital pen 60 is not rotated with respect to the code image pattern formed on the print document 90. In order to help understanding, the unit code patterns included in the code image data are virtually indicated by broken lines in the diagrams of the code image data.

  As shown in FIG. 19B, when the axis of the digital pen 60 is not inclined with respect to the print document 90, the code pattern image formed near the reading position R is hardly distorted by the infrared CMOS chip 641. Will be read in the state. Therefore, each unit code pattern constituting the code pattern image has substantially the same area, and each has a substantially square shape. As a result, as shown in the figure, the number of unit code patterns existing in the first imaging area S1 is substantially equal to the number of unit code patterns existing in the second imaging area S2 (FIG. 19 ( It is equal in b).

  On the other hand, as shown in FIG. 19A, when the axis of the digital pen 60 is inclined in the α direction with respect to the print document 90, the code pattern image formed near the reading position R is an infrared CMOS. Reading is performed in a distorted state by the chip 641. More specifically, in the infrared CMOS chip 641, the image is reduced in the region on the X direction side that approaches the printed document 90 with the inclination in the α direction, and in the region on the −X direction side that is the opposite side. The image is magnified. Therefore, each unit code pattern constituting the code pattern image has a different area, and each has a distorted quadrangular shape. As a result, as shown in the figure, the unit codes existing in the second imaging region S2 closer to the print document 90 than the number of unit code patterns existing in the first imaging region S1 far from the print document 90 are obtained. The number of patterns is larger.

  On the other hand, as shown in FIG. 19C, when the axis of the digital pen 60 is inclined in the β direction with respect to the print document 90, the code pattern image formed near the reading position R is an infrared CMOS chip 641. Thus, the image is read in a distorted state opposite to that in FIG. That is, in the infrared CMOS chip 641, the image is reduced in the −X direction side region that approaches the printed document 90 with an inclination in the β direction, and the image is enlarged in the opposite X direction side region. . Therefore, each unit code pattern constituting the code pattern image has a different area, and each has a distorted quadrangular shape. As a result, as shown in the drawing, the unit codes existing in the second imaging region S2 farther from the print document 90 than the number of unit code patterns existing in the first imaging region S1 close to the print document 90 are obtained. The number of patterns is smaller.

In the present embodiment, as described with reference to FIG. 3, there are always two dots in each unit code pattern. Therefore, for example, the first dot number D1 that is the total number of dots in the first imaging region S1 and the second dot number D2 that is the total number of dots in the second imaging region S2 are unit code patterns included in each region. It will reflect the number of. For this reason, for example, if the first dot number D1 is smaller than the second dot number D2 (D1 <D2), it can be considered that the digital pen 60 is inclined in the α direction as shown in FIG. On the other hand, for example, if the first dot number D1 is larger than the second dot number D2 (D1> D2), it can be considered that the digital pen 60 is inclined in the β direction as shown in FIG. On the other hand, for example, if the first dot number D1 and the second dot number D2 are equal (D1 = D2), it can be considered that the digital pen 60 is not inclined as shown in FIG.
Therefore, in this embodiment, in order to grasp the distortion of the code pattern image obtained by the infrared CMOS 64, the first dot number D1 and the second imaging region S2 existing in the first imaging region S1 are used. The number of existing second dots D2 is counted, and the inclination direction of the digital pen 60 with respect to the print document 90 is determined from the magnitude relationship.

  Here, the case where the digital pen 60 is inclined only in the U direction or the −U direction with respect to the print document 90 has been described as an example. However, in actual use, the digital pen 60 is further in the V direction or −V. It can tilt in the direction. However, even in such a case, the relationship between the first dot number D1 and the second dot number D2 changes corresponding to the inclination of the digital pen 60 in the U direction or the -U direction as described above. Since there is no change, there is no particular problem.

(Relationship between tilt of digital pen and infrared LED to be lit)
FIG. 20 is a diagram illustrating an example of the relationship between the infrared LED 63 to be lit and the reflected light distribution from the print document 90 when the axis of the digital pen 60 is inclined in the α direction. Here, FIG. 20A shows a case where the first infrared LED 63a is turned off and the second infrared LED 63b is turned on, and FIG. 20B shows that the first infrared LED 63a is turned on and the second red LED 63b is turned on. A case where the outer LED 63b is turned off is shown.

  In the present embodiment, the printed pattern 90 is irradiated with infrared light by the first infrared LED 63a or the second infrared LED 63b, and the reflected light is received by the infrared CMOS 64, thereby reading the code pattern image. ing. Here, the reflected light from the printed document 90 includes regular reflected light reflected at the same reflection angle as the irradiation angle (incident angle) of infrared light with respect to the printed document 90 and diffuse reflection reflected at various reflection angles. There is light. At this time, the intensity of the regular reflection light from the printed document 90 tends to be higher than that of the diffuse reflection light.

For example, in the state shown in FIG. 20A, the specularly reflected light emitted from the second infrared LED 63 b and reflected by the print document 90 is received by the infrared CMOS 64. In such a case, saturation occurs in the read data of the code pattern image by the infrared CMOS 64, so that so-called whitening is likely to occur, and it becomes difficult to obtain identification information and position information from the code pattern image. End up.
On the other hand, for example, in the state shown in FIG. 20B, diffuse reflected light that is emitted from the first infrared LED 63 a and reflected by the print document 90 is received by the infrared CMOS 64. In such a case, the above-described whiteout is unlikely to occur, and therefore it becomes easy to obtain identification information and position information from the code pattern image.

  Therefore, in the present embodiment, for example, when the first dot number D1 is greater than or equal to the second dot number D2, and it is estimated that the axis of the digital pen 60 is inclined in the α direction, that is, the second infrared LED 63b. Is turned on, the first infrared LED 63a is turned on and the second infrared LED 63b is turned off. For example, when the first dot number D1 is less than the second dot number D2 and the axis of the digital pen 60 is estimated to be inclined in the β direction (see FIG. 19C), that is, the first red When there is a possibility that whiteout may occur by turning on the outer LED 63a, the second infrared LED 63b is turned on and the first infrared LED 63a is turned off.

  Further, according to the experiment by the present inventor, it has been found that the intensity of specularly reflected light increases within an angle range of 5 degrees. For this reason, in the present embodiment, as described with reference to FIG. 9, the first angle θ <b> 1 formed by the first illumination optical axis and the light receiving axis from the first infrared LED 63 a toward the reading position R and the second angle are set. The sum of the second angle θ2 formed by the second illumination optical axis and the light receiving axis from the infrared LED 63b toward the reading position R is set to 10 degrees or more. Thus, for example, as shown in FIG. 20B, even when the first infrared LED 63a is turned on with the axis of the digital pen 60 tilted in the α direction, the regular reflection light from the print document 90 is not generated. The infrared CMOS 64 prevents light from being received.

  In the present embodiment, when the first dot number D1 and the second dot number D2 are equal, control is performed to turn off the first infrared LED 63a and turn on the second infrared LED 63b. However, in the case of D1 = D2, on the contrary, the control to turn off the second infrared LED 63b and turn on the first infrared LED 63a may be performed.

  In this embodiment, the tilt direction of the axis of the digital pen 60 is determined from the counting results of the first dot number D1 and the second dot number D2. However, the present invention is not limited to this. For example, using the fact that the angle of the virtual lattice shown in FIG. 16B is distorted according to the tilt direction of the axis of the digital pen 60, the tilt direction of the axis of the digital pen 60 is determined based on the distortion of the angle of the virtual lattice. You may make it do. However, in this case, it is necessary to determine the angles of the virtual lattices one by one, not by the average value. Further, for example, on the printed document 90, distortion is detected from the coordinates of each synchronization code obtained by reading the four synchronization codes in the code pattern image arranged in a square shape with the infrared CMOS 64, and the digital is based on the distortion. The tilt direction of the axis of the pen 60 may be determined. In addition to this, as long as the inclination direction of the axis of the digital pen 60 is determined using the distortion of the code pattern image captured by the infrared CMOS 64, the design may be changed as appropriate.

  In the present embodiment, the digital pen 60 having the first infrared LED 63a and the second infrared LED 63b as the infrared LED 63 has been described. However, the present invention is not limited to this, and three or more infrared LEDs are used. Of course, it may be provided. In the case where three or more infrared LEDs are provided, for example, two infrared LEDs out of three may be controlled to be lit.

It is the figure which showed an example of the structure of the handwriting information management system of this Embodiment. It is an explanatory view of an example of a unit code pattern of the code pattern image _{(9 C 2).} It is a view showing a dot arrangement of the 36 types that can take the unit code pattern of ₉ C _2. It is a diagram showing a combination of synchronization code that can be selected from the dot arrangement of 36 types that can take the unit code pattern of ₉ C _2. It is the figure which showed an example of the code block for embedding a synchronous code, a position code, and an identification code. It is the figure which showed an example by which the position code is arrange | positioned in the code pattern image. It is the figure which showed an example by which the identification code is arrange | positioned in the code pattern image. It is a figure explaining the outline of a structure of a digital pen. It is the figure which looked at 1st infrared LED, 2nd infrared LED, and infrared CMOS which comprise a digital pen from the IX direction shown in FIG. It is a figure which shows an example of a structure of the infrared CMOS provided in the digital pen. It is the block diagram which showed an example of the structure of the control part provided in the digital pen. It is the block diagram which showed an example of the structure of the image process part of a control part. It is a figure which shows an example of the result of having detected the proximity | contact dot pair. It is a figure which shows an example of the process which selects a reference | standard dot pair. 6 is a diagram illustrating an example of a result of selecting a reference dot pair and an example in which the reference dot pair is arranged in a coordinate system including a reference axis X and a reference axis Y. FIG. It is the figure which showed an example of the virtual lattice produced based on the rotation angle of the code | symbol pattern image detected by this Embodiment, and the specific example of the synchronization process using the virtual lattice. It is a figure explaining the outline | summary of an example of the process which detects the boundary of the unit code pattern in this Embodiment. It is the flowchart which showed an example of lighting switching control of the infrared LED in a digital pen. It is a figure for demonstrating the relationship between the inclination of the digital pen with respect to a printed document, and the distortion of the read image by infrared CMOS. It is a figure for demonstrating the relationship between the inclination of a digital pen, the infrared LED to light, and the reflected light from a printed document.

Explanation of symbols

60 ... Digital pen, 61 ... Control unit, 611 ... Overall control unit, 612 ... Light emission control unit, 613 ... Light reception control unit, 614 ... Image processing unit, 62 ... Pen pressure detection switch, 63 ... Infrared LED, 63a ... No. 1 infrared LED, 63b ... 2nd infrared LED, 64 ... infrared CMOS, 91 ... image acquisition unit, 92 ... noise removal unit, 93 ... binarization processing unit, 94 ... dot position detection unit, 95 ... reference dot Pair detection unit, 96 ... Angle detection unit, 97 ... Decoding unit, 98 ... Pen tilt detection unit, 98a ... Dot distribution counting unit, 98b ... Pen tilt determination unit

Claims (12)

A plurality of irradiation means for irradiating the medium on which the code image is formed;
Reading means for turning on any one of the plurality of irradiation means and reading the code image from the medium irradiated with light by the illuminated irradiation means;
A determination unit that determines an inclination direction of the apparatus with respect to the medium from an inclination of the code image read by the reading unit;
A reading apparatus comprising: a switching unit that switches an irradiation unit to be lit among the plurality of irradiation units according to the tilt direction determined by the determination unit. The plurality of irradiation means includes a first irradiation means and a second irradiation means for irradiating light toward the reading position of the medium by the reading means,
When the specularly reflected light that is irradiated by the first irradiating unit and reflected by the medium is incident on the reading unit, the specularly reflected light that is irradiated by the second irradiating unit and reflected by the medium is The reading apparatus according to claim 1, wherein an irradiation direction of light of each of the first irradiation unit and the second irradiation unit is set so as not to enter the reading unit. The plurality of irradiation means includes a first irradiation means and a second irradiation means for irradiating light toward the reading position of the medium by the reading means,
A first optical axis from the first irradiating means to the reading position and a second optical axis from the second irradiating means to the reading position are directed from the reading position to the reading means. 3. The reading apparatus according to claim 1, wherein the reading apparatus has a symmetrical positional relationship with respect to the three optical axes. The reading means includes a light receiving sensor having a light receiving region for receiving reflected light from the medium,
The determination unit counts the number of code images acquired in each area obtained by dividing the light receiving area into a plurality of areas, and obtains the inclination of the code image from the obtained count results for each area. The reading device according to any one of claims 1 to 3.   5. The reading apparatus according to claim 1, further comprising an acquisition unit configured to acquire predetermined information embedded in the code image from the code image read by the reading unit.   The reading apparatus according to claim 1, further comprising writing means for writing on the medium. A medium on which a code image is formed;
In response to a user's writing operation on the medium, an electronic writing instrument that reads the code image from the medium;
Information for acquiring information related to the code image read by the electronic writing instrument and storing the writing content on the medium in association with the medium or an electronic document printed on the medium based on the acquired information A processing device,
The electronic writing instrument is:
Writing means for writing on the medium;
A plurality of irradiation means for irradiating the medium with light;
Reading means for turning on any one of the plurality of irradiation means and reading the code image from the medium irradiated with light by the illuminated irradiation means;
Transmitting means for transmitting the information related to the code image read by the reading means to the information processing apparatus;
A determination unit that determines an inclination direction of the apparatus with respect to the medium from an inclination of the code image read by the reading unit;
A writing information processing system comprising: a switching unit that switches an irradiation unit to be turned on from among the plurality of irradiation units according to the tilt direction determined by the determination unit. The code image formed on the medium is configured by arranging a plurality of unit code pattern images formed by arranging a certain number of unit images in a predetermined section in two directions orthogonal to each other,
In the electronic writing instrument,
The reading means includes a light receiving sensor having a light receiving region for receiving reflected light from the medium,
The determination means respectively counts the number of unit images acquired in each area obtained by dividing the light receiving area into a plurality of areas, and obtains the inclination of the code image from the obtained count results for each area. The writing information processing system according to claim 7. The electronic writing instrument obtains identification information of the medium or position information in the medium as the information related to the code image from the code image read by the reading means, and outputs the information to the transmission means Further including
9. The information processing apparatus according to claim 7, wherein the information processing apparatus reads out an electronic document associated with the identification information and superimposes a writing locus corresponding to the position information on the electronic document. Written information processing system. A lighting instruction means for lighting one of the light sources among a plurality of light sources that emit light to the medium on which the code image is formed;
Read instruction means for reading the code image from the medium irradiated with light from the light source that is lit,
Determination means for determining the inclination direction of the reading apparatus with respect to the medium from the inclination of the read code image;
A control device for a reading apparatus, comprising: a switching instruction unit that outputs an instruction to switch a light source to be turned on from among the plurality of light sources to the lighting instruction unit according to the tilt direction determined by the determination unit. On the computer,
A function of turning on one of the light sources among a plurality of light sources that irradiate the medium on which the code image is formed;
A function of reading the code image from the medium irradiated with light from the lit light source;
A function of determining an inclination direction of the apparatus with respect to the medium from an inclination of the read code image;
A program for realizing a function of switching a light source to be turned on from among the plurality of light sources in accordance with the determined inclination direction. In the computer,
The program according to claim 11, further realizing a function of acquiring predetermined information embedded in the code image from the read code image.

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