JPH03201766A - Original input device - Google Patents

Abstract

PURPOSE:To make an original input device compact by preparing plural optical filters having different wavelength characteristics and arranging an optional filter among them between an image sensor and a light source. CONSTITUTION:Since the device is designed such that not only one of three primary colors is selected and radiates to an original 12 but also two of the original colors are mixed at a prescribed ratio and the resulting color radiates to the original, two filters are used for one color only. That is, a strip shaped transparent section 21A is arranged axially to a fluorescent lamp 21 inserted in a filter unit 29 and a ray 71 mainly radiates therefrom. In this case, since the transparent section 21A radiates almost a border area between a 1st filter 54-1 and a 2nd filter 54-2, a light in which red and green wavelength components are mixed nearly equally radiates from the filter unit 29 to the original 12. Thus, it is not required to prepare light source of different wavelengths and the light of various wavelength characteristics is used as the light source, then the device is made compact.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document input device for inputting an image of a document, and particularly to a document input device for inputting an image of a document. The present invention relates to a document input device configured to obtain image data representing a document.

``Prior art'' Early image input devices for inputting image information of a document were mainly devices that converted the scanned image into binarized data and output it, as typified by the reading section of a normal facsimile machine. Ta. The majority of manuscripts to be read are those whose original images can be sufficiently reproduced by binarization, such as printed matter or handwritten manuscripts.

However, as image processing technology progressed rapidly and it became possible to print out halftones using pseudo halftone reproduction methods such as the dither method, manual manuscript machines that could read the image information of a manuscript in multiple values became available. are starting to appear more frequently.

``Problem to be solved by the invention'' With the advancement of image technology, manuscripts that use abundant halftones, such as photographs and paintings, which were traditionally avoided, are now being input into manuscript input devices. It has become a target.

Many of these manuscripts are expressed in multiple colors or in color. However, when an image of a colored original is inputted using an original input device and reproduced in a single color such as black and white, the original may give a very different impression from the previous original. especially,
Portions that could be clearly identified in a colored original are rendered in a single color, making them difficult to identify, or parts of the image become indistinguishable from other parts of the image and disappear as an image. There were times when I would put it away.

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide a document input device that can change image reading characteristics depending on the condition of the document.

A second object of the present invention is to provide a document input device that can automatically select image reading characteristics depending on the condition of the document.

"Means for Solving the Problem" The invention according to claim 1 includes: (i) a light source for illuminating a document;
(ii) An image sensor such as a one-dimensional image sensor that receives the light reflected from the original by this light source, and (iii)
The document manual apparatus is equipped with a plurality of optical filters each having different wavelength characteristics, and (iv) optical filter selection means for disposing any one of these optical filters between the image sensor and the light source.

That is, in the first aspect of the invention, a plurality of optical filters are prepared and selectively arranged between the image sensor and the light source.

There are three possible ways to arrange the optical filters:

(b) A mode in which an optical filter is placed around the light source.

(b) A mode in which an optical filter is placed in the optical path between the light source and the image sensor.

(c) A mode in which an optical filter is placed in front of the image sensor.

In the invention according to claim 2, (1) a light source for illuminating a document;
(ii) an image sensor that receives the light reflected from the original by this light source; (iii) a plurality of optical filters each having different wavelength characteristics; (iv) a position specifying means for specifying a plurality of positions on the original; V) Optical filter selection means for disposing any one of these optical filters between the image sensor and the light source; (vii) a density difference calculating means that calculates a density difference between the image data of each optical filter read by the prescanning means; (vii) The document input device is provided with a density difference comparing means for comparing the magnitude of the difference for each optical filter, and a document reading means for selecting the optical filter with the maximum density difference (ix>maximum) and performing the original reading of the document. .

In other words, in the invention according to claim 2, the specified 2
A plurality of points, such as a dot, are pre-scanned while changing the characteristics of the optical filter, the density difference is determined for each, and the optical filter with the maximum density difference is selected to perform the original reading of the document.

"Example" Hereinafter, the present invention will be described in detail with reference to Examples.

FIG. 1 shows an outline of the configuration of a document input device according to an embodiment of the present invention. This document input device 11 has a platen glass 13 for placing a document 12 on the top surface of a box-shaped main body, and inside the main body there is a scanning unit 14 and a guide rail 15 for reciprocating the scanning unit 14. It is located. A standard density plate 16 is arranged on the back side of the upper panel of the main body adjacent to the end of the platen glass 13 on the scanning start side. The main motor 17 located at the bottom of the device body is the main motor 17 of the scanning unit 1.
It is used as a driving source for the reciprocating motion of 4.

The scanning unit 14 includes a fluorescent lamp 21 for illuminating the original 12 in a line, and a one-dimensional image sensor 22 for photoelectrically converting light reflected from the original 12. A video signal output from the one-dimensional image sensor 22 in synchronization with a clock signal is input to an input circuit 23, where it is amplified and then AD converted.

The image data after AD conversion is supplied to the electronic circuit section 25,
After undergoing processing such as gradation correction, the image is sent to an image editing device (not shown) through a cable 26. The electronic circuit section 26 also controls the main motor 17 and the drive of a filter motor 28 disposed within the scanning unit 14 . The filter motor 28 rotates a filter unit 29 rotatably disposed around the fluorescent lamp 21. The position control of the filter unit 29 is performed by an optical sensor 31, as will be explained in detail later.

An operation panel 33 is arranged near the platen glass 13 on the upper surface of the document input device 11 for performing various operations when inputting the document 12. Although not shown in FIG. 1, a digitizer as a tool for specifying a desired location on the original 12 is connected to the original input device 11.

FIG. 2 shows the circuit configuration of the document input device, centering on the electronic circuit section. The electronic circuit unit 26 includes a CPU (Central Processing Unit) 41 that serves as the center of various controls.The CPU 41 is connected to the following units via a bus 42 such as a data bus.

(i) ROM 43: This is a read-only memory that stores programs for performing various controls of this manuscript input device 11.

(ii) RAM44: Random access for work.
It's memory. This RAM44 contains standard density play)
A correction data storage area 44A for storing the correction data read in step 16, a position data storage area 44B for storing position data for checking the irradiation light on the original 12, and a density difference at each position. A density difference storage area 44C for storing each filter, a filter selection data storage area 44D for storing the type of selected filter,
Various areas are allocated, such as a pulse number storage area 44E for storing the number of pulses for positioning the selected filter.

(iii) Input circuit 23: As explained earlier, inputs the outputs of the one-dimensional image sensor 22 and optical sensor 31,
This is a circuit for transferring data to the bus 42.

(iv) Lamp lighting circuit 46: This is a circuit for controlling lighting of the fluorescent lamp 21.

(V) Filter motor drive circuit 47: Filter motor 2
This is a circuit for controlling the drive of 8.

(vi) Main motor drive circuit 48: Main motor 17
This is a circuit for controlling the drive of the

(vj) Operation panel 33: Various key switches and a liquid crystal display board are arranged, from which the operator can input necessary data and set various modes.

(vi) Digitizer 49: A coordinate input device that can specify a desired area or point on the document 12.

(ix) Output circuit 50: This is a circuit for sending the image data stored in the RAM 44 to the cable 26 at a predetermined transfer rate.

FIG. 3 shows the filter unit and the mechanism for rotating it. The filter unit 29 has two discs 51 and 52 of the same diameter arranged oppositely,
It has a structure in which five pillars 53 are placed between them at equal intervals. A filter plate 54 whose cross section is a part of a circular arc is attached between each support column 53 . The first disk 51 has teeth carved at a predetermined pitch on its outer periphery, and meshes with a gear 56 attached to the rotating shaft of the filter motor 28. 1st and 2nd
A bearing 58 is disposed between the discs 51 and 52 and the pair of fluorescent tube fixtures 57 and 57. In addition, the first disk 51
A small hole 59 is bored at a predetermined position, and a light beam emitted from the hole to the outside is made incident on the optical sensor 31 at a predetermined rotational position.

FIG. 4 shows a longitudinal section of the filter unit with a fluorescent lamp attached.

Inside the filter unit 29, an amphibious light tube fitting 57 is installed.
The fluorescent lamp 21 is inserted into the electrode insertion hole 61 of the fluorescent lamp 21.
is located. Each electrode insertion hole 61 of the fluorescent tube fixture is electrically connected to a corresponding electrode 63.

Therefore, by inserting these four electrodes into the fluorescent lamp electrode holes (not shown) and fixing the fluorescent tube fixtures 57, 57, the fluorescent lamp 21 can be turned on.

Filter motor 28 composed of a step motor
When driven in this state, the two discs 51, 52 rotate accordingly. The small holes 59 are formed on the desired filter plate 5.
4 is used for positioning for irradiating the original 12 with the light.

FIG. 5 shows a cross section of the filter unit with a fluorescent lamp attached.

The first to fifth filters 54-1 to 54-5 used in the filter unit 29 have the following optical characteristics.

(a) First filter 54-1: This is an R filter, which transmits only the R (red) portion shown in FIG. 6.

(b) Second filter 54-2: This is a G filter, which transmits only the G (green) portion shown in FIG.

(c) Thirteen filter 54-3: This is a B filter, which transmits only the B (blue) portion shown in FIG.

(iv) Fourth filter 54-4: This is an R filter and is similar to the first filter 54-1. The document input device 11 of this embodiment not only selects one of the three primary colors and irradiates the document 12, but also irradiates the document 12 by mixing two of these primary colors at a predetermined ratio. , two additional filters are used for only one color.

(E) Fifth filter 54-5: A transparent (T) filter that transmits each wavelength of light as it is. This fifth filter 54-5 is selected when the original 12 is irradiated with normal white light. It is something that will be done.

Fluorescent lamp 21 inserted into filter unit 29
has a band-shaped transparent portion 21A arranged in its axial direction,
The light rays 71 are mainly emitted from here. In the example shown in FIG. 5, since the transparent portion 21A illuminates almost the boundary area between the first filter 54-1 and the second filter 54-2, the red and green wavelengths are emitted from the filter unit 29. Light in which the components are mixed almost equally is emitted and is irradiated onto the original 12.

FIG. 7 shows the characteristics of the reflected wavelength when white light is irradiated onto a certain part of the document. This corresponds to the case where the document (2) is irradiated using the fifth filter 54-5.

FIG. 8 shows the characteristics of the reflected wavelength when the same document portion is irradiated using the first filter 54-1 or the fourth filter 54-4. R (red)
It can be seen that the reflection level in the wavelength range is emphasized.

FIG. 9 shows the characteristics of the reflected wavelength when the same document portion is irradiated using the second filter 54-2. It can be seen that the reflection level in the G (green) wavelength range is emphasized.

FIG. 10 shows the characteristics of the reflected wavelength when the same document portion is irradiated using the third filter 54-3. It can be seen that the reflection level in the B (blue) wavelength range is emphasized.

How an image of an actual document is read will be explained using FIGS. 11 to 15.

FIG. 11 shows a document to be read. Three characters R, G, and B are drawn on this manuscript 12. Of these, the letter rRj is scratched with red, the letter "G" with green, and the letter rBJ with a blue writing instrument.

FIG. 12 shows a case where reading is performed using the fifth filter 54-5 and recording is performed with a printer (not shown). R
, GSB are read at almost the same density, and as a result, the three characters RlG and B are recorded on the recording paper 73 at these densities.

FIG. 13 shows an example using the first filter 54-1. In this case, only the light component of the red wavelength is irradiated onto the original 12, so that the reflectance of the white background portion of the original 12 and the letters rRJ are approximately equal. That is, both the character "R" and the background part become at the "red" level, and the character rRJ is erased on the recording paper 73.

FIG. 14 shows an example using the second filter 54-2. In this case, only the green wavelength light component is irradiated onto the original 12, so that the reflectance of the white background portion of the original 12 and the letter "G" are approximately equal. In other words, both the letter "G" and the background part are at the "green" level, and the letter "G" is erased on the recording paper 73.

FIG. 15 shows an example using the third filter 54-3. In this case, only the blue wavelength light component is irradiated onto the original 12, so that the reflectance of the white background portion of the original 12 and the letters rBJ are approximately equal. That is, both the character rBJ and the spine JL become at the "blue" level, and the character rBJ is erased on the recording paper 73. In addition, Figure 13~! In FIG. 15, since the background level is adjusted when the original 12 is read, the background portions of these recording sheets 73 are both expressed as a white level.

FIG. 16 shows an overview of the reading operation centered on control for setting the wavelength characteristic of the light beam output from the filter unit described above to a desired value. When the start button on the operation panel 33 of the original input device 11 is pressed to instruct the start of image input work (the first
6, step ■; Y), the CPU 46 controls the lamp lighting circuit 46 to light the fluorescent lamp 21 (step ■).Then, the CPU 46 controls the filter motor drive circuit 47 to start driving the filter motor 28. (Step ■). The filter motor 28 is driven until the optical sensor 31 can detect the light from the fluorescent lamp 21 through the small hole 59 shown in FIG. 3 (Step ■). If it is done (Y), the filter unit 29 is set to the home position.At this time, the 5th v
The transparent portion 21A of the fluorescent lamp shown in g:J faces the fifth filter 54-5. That is, when using the light source as white light, the document 12 can be read in this state with the filter unit 29 set at the home position.

After the filter unit 29 is set to the home position in this manner, the number of pulses corresponding to the wavelength characteristics specified by the apparatus is set (step (2)). This number of pulses is the number of pulses required to rotate the filter unit 29 by a desired angle by driving the filter motor 28. This number of pulses is stored in the pulse number storage area 44E of the RAM 44 and will be read out.
This will be explained using Figure 7.

When the number of pulses is set, the CPU 41 determines whether the set value is "0" (step ■)
. If it is “0”, white light will be output, so start reading the image with this home position set (step ■).On the other hand, if the number of pulses is “0” If not (step ■; N), CP
U41 starts driving the filter motor 28 (step ■), and when the designated number is reached (step ■; Y), the image reading operation is started at that filter position (step ■).

FIG. 17 specifically shows the work of setting the number of pulses.

When the filter unit 29 is set to the home position in FIG.
determines whether the document reading characteristics are set to automatic mode (Step ■ in Figure 17).The operator selects automatic mode or manual mode in advance by operating the operation panel 33 (Figure 2). can do.

If it is set to manual mode (N), CPU4
Step 1 checks whether a filter has been specified on the operation panel 33 (step ■). This is done by checking whether the type of filter is registered in the filter selection data storage area 44D. If the designation has been made (Y), the number of pulses required for the designated filter to come to the home position is read out from the ROM 43 and stored in the pulse number storage area 44E of the RAM (step 2). On the other hand, if manual mode is set but no filter is specified (
Step 2; N), "0" is stored in the pulse number storage area 44E as the number of pulses (Step 2). At this time, the fifth filter 54-5 is in the fixed position, and the original 12 is irradiated with white light, as described above.

Next, a description will be given of a case where the operator has selected automatic mode. In this case, the CPU 41 causes a display to be displayed on the liquid crystal display panel of the operation panel 33 to prompt the digitizer 49 to specify the position (step 2). For example, "Use the digitizer to specify the two points you want to identify." is displayed. This display continues until the operator specifies the positions (step ■).

FIG. 18 shows how the position is designated. The operator sets the original 12 at a predetermined position on the digitizer 49 and specifies the positions of, for example, two points 81 and 82 using a special pen or the like. These points correspond to portions of the document 12 that are desired to be read separately.

Once the position is specified, the data is stored in the position data storage area 44B in the RAM 44 (step ■).
. Then, the first-stage filter settings are performed (step ■). In the first stage, the fifth filter 54-5 is set at the initial position of the filter unit 29, so there is no need to drive the filter motor 28 for this purpose. With the fifth filter 54-5 set, a first prescan regarding the two positions stored in the position data storage area 44B is performed. That is, image data of two points 81 and 82 are respectively read while being irradiated with white light. These image data are AD converted, and the density difference is determined. The density difference is RAM4
The data is stored in the density difference storage area 44C in 4 in association with the filter type (step 2).

In the document input device 11 of this embodiment, transparent, red,
Similar operations are performed while setting filters for the three primary colors of green and blue. Therefore, the CPU 41 checks whether these tasks have been completed (step ■), and if they have not been completed (N
〉, set the following filter and perform the same operation (steps ■~■). The second filter 54-1 is set, the third filter 54-2 is set,
The third filter 54-3 is set fourth. Note that the first filter 54-1 and the second filter 5
It is also possible to perform more filter settings by using intermediate positions such as 4-2.

When the measurement of the density difference for each filter 54 by pre-scanning is completed (step 0; Y), the CPU 41 selects the filter corresponding to the maximum density difference stored in the density difference storage area 44C, and stores this value. is stored in the filter selection data storage area 44D (step ■).Then, the filter unit 29 is returned to the initial position (step 0).The work in step 0 is similar to the work in steps ■ and ■ in FIG. be.

When the filter unit 29 is set to the initial position, the number of pulses corresponding to the designated filter is read out from the ROM 43 and stored in the pulse number storage area 44E of the RAM (step 2).

The following Table 1 shows the two points 81. specified by the digitizer 49.
4 filters 54-5.54-1,54 for 82
-2.54-3 measurement results are shown.

Table 1 In this example, if the first filter 54-1 is used, the density difference will be maximized, so this filter will be selected for the work in step (2) in FIG.

In addition, in the example explained above, two points are specified and the filter that maximizes the density difference between them is selected, but this may make the density difference with other color tones unclear. There may be cases.

Therefore, in order to solve this problem, it is recommended to select three or more points using a coordinate specifying means such as a digitizer, and select the filter that maximizes the density difference between these points. .

Furthermore, in the embodiment, a cylindrical filter unit was covered around the fluorescent lamp, but a polygonal filter unit was covered.
This may be rotated. For positioning the filter, it is not necessary to use gears as in the embodiment, and the rotational force may be transmitted to the rotating shaft of the filter using a belt. Furthermore, setting the initial position of the filter is not limited to an optical sensor, and it is also possible to use other sensors such as a magnetic sensor.

Further, in the embodiment, a filter that directly covers the fluorescent lamp or the light source is used, but it is of course possible to switch the filter in the optical path between the light source and the document or in a position immediately in front of the image.

"Effects of the Invention" As explained above, according to the invention described in claim 1, a plurality of optical filters each having different wavelength characteristics are prepared, and any one of them is connected to the image sensor and the light source. Since it is arranged between the two, it is possible to use light with various wavelength characteristics as a light source without preparing light sources of different wavelengths, so that the document input device can be manufactured compactly.

Further, according to the invention as set forth in claim 2, a plurality of optical filters each having different wavelength characteristics, a position specifying means for specifying a plurality of positions on the document, and an optical filter for each position specified by the position specifying means. Pre-scanning means for pre-scanning while sequentially selecting optical filters one by one with a selection means, and density difference calculation means for calculating a density difference between image data for each optical filter read by the pre-scanning means. Therefore, the optimum filter characteristics for reading a document can be easily obtained without requiring any experience from the operator. In addition, since documents are read with the most suitable filter set, when combined with an automatic document feeder, various types of documents can be read with the most suitable filter without the intervention of an operator, greatly streamlining office work. can be achieved.

[Brief explanation of drawings]

The drawings are for explaining one embodiment of the present invention. Among them, FIG. 1 is a schematic configuration diagram of a document input device, and FIG. 2 is a block diagram showing the circuit configuration of the document input device, centering on the electronic circuit section. 3 is a perspective view showing the filter unit and the mechanism for rotating it, and FIG. 4 is a vertical sectional view of the filter unit with a fluorescent lamp attached.
Figure 5 is a cross-sectional view of the filter unit with a fluorescent lamp attached, Figure 6 is a characteristic diagram showing the characteristics of each colored filter, and Figure 7 is a part of the document irradiated with white light. Figure 8 is a characteristic diagram showing the characteristics of the reflected wavelength in the case of using the first filter or the fourth filter.
A characteristic diagram showing the characteristics of the reflected wavelength when the same part of the original as shown in the figure is irradiated. Figure 9 shows the characteristics of the reflected wavelength when the same part of the original as shown in Fig. 7 is irradiated using the second filter. Figure 10 is a characteristic diagram showing the characteristics of the reflected wavelength when the same document part as in Figure 7 is irradiated using the third filter, and Figure 11 is the target of reading. A plan view showing an example of a document; FIG. 12 is a plan view showing a recording surface when read using the fifth filter;
FIG. 13 is a plan view showing the recording surface when reading using the first filter, FIG. 14 is a plan view showing the recording surface when reading using the second filter, and FIG. 15 is a plan view showing the recording surface when reading using the second filter. A plan view showing the recording surface when read using the third filter, Fig. 16 is a flowchart showing an overview of the reading work, and Fig. 17 specifically shows the setting work of the number of pulses in Fig. 16. FIG. 18 is a plan view showing how the position is designated by the digitizer. 11... Original input device, 12... Original, 14... Scanning unit, 21...
...Fluorescent lamp, 22...One-dimensional image sensor, 25...
...Electronic circuit section, 28...Filter motor, 2
9...Filter unit, 33...Operation panel, 41...CPU
. 43...ROM, 44...RAM. 44B...Position data storage area, J? :)1
Fig. 4C...Concentration difference storage area, 4D...Filter selection data storage area, 4E...
... Pulse number storage area, 9 ... Digitizer, 4-1 ... First filter, 4-2 ... Second filter, 4-3 ...Third filter, 4-4...Fourth filter, 4-5...Fifth filter.

Claims (1)

[Claims] 1. A light source for irradiating a document, an image sensor into which light reflected from the document by the light source is incident, a plurality of optical filters each having different wavelength characteristics, and any one of these optical filters. A document input device comprising: an optical filter selection means, one of which is disposed between the image sensor and the light source. 2. A light source for irradiating the original, an image sensor that receives light reflected from the original by this light source, a plurality of optical filters each having different wavelength characteristics, a position specifying means for specifying a plurality of positions on the original, and these an optical filter selection means for disposing any one of the optical filters between the image sensor and the light source; and an optical filter selection means for sequentially selecting the optical filters one by one at each position designated by the position designation means. Pre-scanning means for pre-scanning while selecting; density difference calculation means for calculating the density difference between the image data of each optical filter read by the pre-scanning means; and comparing the magnitude of the density difference for each optical filter. What is claimed is: 1. A document input device comprising: a density difference comparing means; and a document reading device which selects an optical filter with a maximum density difference and performs original reading of the document.