JP2013226397A - Apparatus for measuring objective near field distance and method and system for manufacturing spectacle lens using the apparatus for measuring objective near field distance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for measuring objective near field distance which is capable of measuring an objective near field distance in a more similar state to an actually using environment of a pair of glasses.SOLUTION: An apparatus for measuring objective near field distance includes an imaging device for simultaneously imaging an eyeball of a subject and a near field object used by wearing a pair of glasses during near field work in one image, a first position identifying device for extracting an area corresponding to the eyeball of the subject from the image taken in the imaging device and identifying the position of the eyeball of the subject on the image as an eyeball position, a second position identifying device for extracting an area corresponding to the near field object from the image taken in the imaging device and identifying the position of the near field object on the image as an object position, and a distance computing device for computing the distance between the eyeball and the object positions as a temporary objective near field distance, and the image is taken for each prescribed interval of times in the imaging device, and the distance computing device requires a real objective near field distance based on the temporary objective near field distance computed for each image.

Description

  The present invention relates to a near-work target distance measuring device used when prescribing a near-use eyeglass lens, and a spectacle lens manufacturing method and a manufacturing system using the near-work target distance measuring device.

  When prescribing spectacle lenses with near function, such as bifocal lenses, progressive power lenses, near-focal lenses, etc., take into account the power of the near part, eye accommodation, distance for near work, etc. In addition, the addition power at the near working distance of the lens wearer is determined. A specific method for setting the addition power is described in Patent Documents 1 and 2, for example.

Japanese Patent No. 4837968 Japanese Patent No. 4880044

  Patent Document 1 describes a configuration in which addition power measurement is performed using a near-sight target presenting device that looks like a book. This device is configured to measure the distance between the subject's eye (the subject's eye) and the device main body, and the subject can move the device main body as appropriate so that the near vision, near point distance, The working distance is measured, and the addition power is obtained from these measurement results. However, the purpose of use of the spectacle lens having a near-use function is not only for reading, but also for operation of a personal computer or a mobile phone, etc. A problem is pointed out that the target distance for near work cannot be measured in a state where the actual usage situation is reproduced. Hereinafter, a visual target in near work such as a book, a personal computer, and a mobile phone is defined as a near work object.

  In addition, the configuration described in Patent Document 1 is for displaying a visual target on a near-field visual target presenting device that looks like a book, and is not a configuration that uses an actual book (that is, an actual usage situation has been reproduced). It is not necessarily a thing), and the subject does not always take the posture when reading a book, and it is pointed out that the near-distance target distance measured may differ from the actual one.

  Patent Document 2 discloses a method for calculating a near work target distance by attaching a distance measuring sensor to a near work object or photographing a subject reading a book from a lateral direction with a camera and analyzing the image. Is described. However, the method of attaching a distance measurement sensor to a near-field object is considered to have a problem in accuracy because there is no guarantee that the distance measurement position is an eyeball. Considering the possibility of an influence, the same problem as that of Patent Document 1 is included. In addition, in the method based on image analysis, the environment at the eyeglass store where the near-distance target distance is measured is different from the environment at home, and the subject may be excessively aware of the near-distance target distance measurement. Therefore, the subject is not necessarily using the near work object in a relaxed posture, and it is pointed out that the near work target distance measured may be different from the actual distance. That is, in the configuration of Patent Document 2, the near work target distance is calculated without determining whether or not the subject is using the near work object in a relaxed state.

  The present invention has been made in view of the above circumstances, and the purpose thereof is a near-work target distance measuring device capable of measuring a near-work target distance in a state close to the actual use environment of glasses, It is another object of the present invention to provide a spectacle lens manufacturing method and system using such a near-work objective distance measuring device.

  A near-work target distance measuring device according to an embodiment of the present invention is a near-work target distance measuring device that measures a near-work target distance of a subject wearing spectacles, the subject's eyeball, and the subject Extracts an area corresponding to the eyeball of a subject from an image pickup apparatus that simultaneously picks up an image of a near work object to be used while wearing glasses during close work work, and an image picked up by the image pickup apparatus The first position specifying means for specifying the position of the eyeball of the subject on the image as the eyeball position, and an area corresponding to the near work object is extracted from the image captured by the imaging device, and the near work object is extracted. A second position specifying means for specifying the position on the image as the object position; a distance calculating means for calculating a distance between the eyeball position and the object position as a temporary near-work target distance; An image is taken every time, and the distance calculation means Each based on near-work target distance provisional calculated for, and obtains the true near-work target distance.

  According to such a configuration, since the temporary near work target distance is measured using the near work object actually used by the subject, the near work target distance according to the use purpose of the subject's glasses is obtained. I want. In addition, in order to obtain the true near-work target distance after monitoring the temporary near-work target distance over time, the near-work purpose when the subject is used to the measurement environment and takes a relaxed posture The distance can be obtained accurately.

  Further, the distance calculation means obtains a temporal change in the temporary near work target distance, and when the change amount falls within a predetermined range for a predetermined time, the temporary near work target distance within the predetermined time An average value can be obtained for, and the average value can be used as a true near-work target distance. According to such a configuration, after confirming that the posture of the subject (that is, the near-distance target distance) is stable (that is, whether the subject takes a relaxed posture) Since the target distance is required, a more accurate near-work target distance can be obtained.

  In addition, a distance image sensor that simultaneously captures a subject's eyeball and near-field object and obtains a distance image, the distance image sensor generates three-dimensional coordinate data of the subject's eyeball and near-field object, The distance calculation means may be configured to calculate a temporary near-work target distance based on the three-dimensional coordinate data corresponding to the eyeball position and the three-dimensional coordinate data corresponding to the object position. In this case, it is preferable that a correspondence relationship between each pixel of the image captured by the imaging device and each pixel of the distance image acquired by the distance image sensor is defined in advance.

  Further, the imaging device can be configured to capture an image from a position where the subject's eyeball and near-work object can be simultaneously captured. In this case, only one near eye target distance can be measured with a single measurement, but since there is actually an order for only one eye lens, it is also preferable to take such a configuration.

  A method for manufacturing a spectacle lens according to an aspect of the present invention includes a step of acquiring a true near-work target distance from the near-work target distance measuring device, and the addition of the spectacle lens based on the acquired true near-work target distance. The method includes a step of setting a power and a spectacle lens manufacturing step of manufacturing a spectacle lens in which the addition power is set. According to such a spectacle lens manufacturing method, it is possible to manufacture a spectacle lens in which an accurate addition power is set according to the purpose of use of the subject's spectacles.

  A spectacle lens manufacturing system according to an aspect of the present invention sets the addition power of a spectacle lens based on the above-mentioned near-work target distance measurement device and the true near-work target distance, and includes a predetermined power including the addition power. An order-side terminal that transmits prescription information as order data, a spectacle lens that receives order data and designs spectacle lenses suitable for prescription, and transmits spectacle lens design data; and a spectacle lens that receives design data And a processing-side terminal for processing. According to such a spectacle lens manufacturing system, it is possible to manufacture a spectacle lens in which an accurate addition power according to the purpose of use of the subject's spectacles is set.

  ADVANTAGE OF THE INVENTION According to this invention, the near work target distance measuring apparatus which can measure a near work target distance in the state close | similar to the actual use environment of spectacles is provided. Moreover, according to the spectacle lens manufacturing method and manufacturing system using such a near-work target distance measuring device, a spectacle lens having an accurate addition power according to the purpose of use of the subject's spectacles is manufactured. It becomes possible.

It is a block diagram which shows the structure of the spectacle lens manufacturing system for implement | achieving the manufacturing method of the spectacle lens of embodiment of this invention. It is a block diagram which shows schematic structure of the near work target distance measuring apparatus of embodiment of this invention. It is a figure which shows the use condition of the near work target distance measuring apparatus of embodiment of this invention. It is a flowchart which shows the processing flow of the near work target distance measurement program performed with the near work target distance measuring apparatus of embodiment of this invention. It is the figure which plotted the temporary near work target distance preserve | saved with the near work target distance measurement program performed with the near work target distance measuring apparatus of embodiment of this invention.

  Hereinafter, a spectacle lens manufacturing system for manufacturing spectacle lenses using a near-work target distance measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.

[Eyeglass lens manufacturing system 1]
FIG. 1 is a block diagram showing a configuration of a spectacle lens manufacturing system 1 for realizing the spectacle lens manufacturing method of the present embodiment. As shown in FIG. 1, a spectacle lens manufacturing system 1 includes a spectacle store 10 that orders spectacle lenses according to a prescription for a customer (a spectacle wearer), and receives spectacle lenses in response to an order from the spectacle store 10. An eyeglass lens manufacturing factory 20 is manufactured. The order to the spectacle lens manufacturing factory 20 is made through a predetermined network such as the Internet or data transmission by FAX. The orderer may include ophthalmologists and general consumers.

[Optical store 10]
The spectacle store 10 is provided with a store computer 100 and a near-work target distance measuring device 150. The store computer 100 is, for example, a general PC (Personal Computer), and is installed with software for ordering eyeglass lenses from the eyeglass lens manufacturing factory 20. Lens data and frame data are input to the store computer 100 through operation of a mouse, a keyboard, and the like by an eyeglass store staff. Further, the near-work target distance measuring device 150 is connected to the storefront computer 100 via a network such as a LAN (Local Area Network) or a serial cable, and the near-work purpose measured by the near-work target distance measuring device 150 is used. The distance is input to the store computer 100.

  The lens data includes, for example, prescription values (spherical refractive power, astigmatic refractive power, astigmatic axis direction, prism refractive power, prism base direction, addition power, distance PD (Pupillary Distance), near-field PD, etc.), wearing spectacle lenses. Conditions (corner apex distance, forward tilt angle, frame tilt angle), spectacle lens types (single focal sphere, single focal aspheric, multifocal (double focal, progressive), coating (dyeing, hard coating, anti-reflection coating) , UV cut etc.)), layout data etc. according to customer's request are included. Note that the storefront computer 100 according to the present embodiment obtains at least a lens prescription value (addition power) based on the near work target distance input from the near work target distance measuring device 150. Regarding the method of obtaining the addition power, since the well-known method described in the above-mentioned Patent Document 1 or 2 can be applied, the description is omitted in this specification.

  The frame data includes the shape data of the frame selected by the customer. The frame data is managed by, for example, a barcode tag, and can be obtained by reading the barcode tag attached to the frame by a barcode reader. The store computer 100 transmits order data (lens data and frame data) to the eyeglass lens manufacturing factory 20 via the Internet, for example.

[Glasses lens manufacturing factory 20]
In the spectacle lens manufacturing factory 20, a LAN centering on the host computer 200 is constructed, and a number of terminal devices such as a spectacle lens design computer 202 and a spectacle lens processing computer 204 are connected. The spectacle lens design computer 202 and the spectacle lens processing computer 204 are general PCs, and a spectacle lens design program and a spectacle lens processing program are installed, respectively. The host computer 200 receives ordering data transmitted from the store computer 100 via the Internet or the like. The host computer 200 transmits the input order data to the spectacle lens design computer 202.

  After receiving the ordering data, the spectacle lens manufacturing factory 20 designs and processes both the inner and outer surfaces of the unprocessed block piece so that the prescription of the intended wearer is satisfied. In the eyeglass lens manufacturing factory 20, in order to improve productivity, the frequencies of the entire production range are divided into a plurality of groups, and the outer surface (convex surface) curve shape (spherical shape or aspherical shape) adapted to the frequency range of each group. ) And a semi-finished blank having a lens diameter may be prepared in advance for the order of spectacle lenses. In this case, the spectacle lens manufacturing factory 20 manufactures spectacle lenses suitable for the prescription of the intended wearer only by performing inner surface (concave surface) processing (and target lens processing).

  The eyeglass lens design computer 202 is installed with a program for designing eyeglass lenses according to orders, creates lens design data based on order data (lens data), and based on order data (frame data). Create the target lens processing data. The spectacle lens design computer 202 transfers the created lens design data and target lens shape processing data to the spectacle lens processing computer 204.

  The operator sets the block piece on the processing machine 206 such as a curve generator, and inputs a processing start instruction to the eyeglass lens processing computer 204. The eyeglass lens processing computer 204 reads the lens design data and the target lens shape processing data transferred from the eyeglass lens design computer 202 and drives and controls the processing machine 206. The processing machine 206 grinds and polishes the inner and outer surfaces of the block piece according to the lens design data, and creates the inner and outer shape of the spectacle lens. Further, the processing machine 206 processes the outer peripheral surface of the uncut lens after creation of the inner surface shape and the outer surface shape into a peripheral shape corresponding to the target lens shape.

  The eyeglass lens after the lens processing is subjected to various coatings such as dyeing, hard coating, antireflection film, and UV protection according to the order data. Thereby, the spectacle lens is completed and delivered to the spectacle store 10.

[Specific Configuration of Near-Work Purpose Distance Measuring Device 150]
FIG. 2 is a block diagram showing a schematic configuration of the near-work target distance measuring device 150 of the present embodiment. FIG. 3 is a diagram illustrating a usage state of the near-work target distance measuring device 150. 3A is a diagram when the subject is viewed from the side, and FIG. 3B is a diagram when the subject is viewed from the front. The near work target distance measuring apparatus 150 is an apparatus for accurately measuring the near work target distance according to the main use purpose of the customer's glasses. As shown in FIG. 3, for example, if the main purpose of use of the customer's glasses is to operate a personal computer, the distance from the subject's eyeball to the personal computer (that is, the actual operation of the personal computer) , Measure the near work objective distance). Further, if the main purpose of use of the customer's glasses is reading, the distance from the subject's eyeball to the book is measured while actually reading. The near-work target distance measuring device 150 only needs to be able to photograph the subject's eyeball and near-work object, and the installation location does not necessarily have to be arranged as shown in FIG. 3 if this condition is satisfied. Further, when using a desk and a chair as shown in FIG. 3, it is desirable to use a desk and a chair having a variable height so that the subject can be brought close to the environment normally used.

  Although details will be described later, the near-work target distance measuring device 150 of the present embodiment incorporates the near-work target and the eyeball of the subject to be measured of the near-work target distance in the near-work target distance measuring device 150. The position of the eyeball of the subject and the near-field object using the images taken by these cameras are arranged at positions (for example, the front of the subject) that can be simultaneously imaged by the camera 155a and the distance image sensor 155b. Are mapped (coordinated) in three dimensions and the distance between them is measured.

  As shown in FIG. 2, the near work target distance measuring device 150 includes a processor 151, a memory 152, a user interface 153, a monitor 154, and an imaging unit 155. Note that the number of imaging units is not limited to one, and a plurality of imaging units may be provided for the purpose of expanding the imaging range.

  The processor 151 is a control device that comprehensively controls each component in the near work target distance measuring device 150. The processor 151 reads and executes the near-work target distance measurement program stored in the memory 152. As will be described later, when the near-work target distance measurement program is executed, the processor 151 controls the imaging unit 155 to acquire image data input from the camera 155a and the distance image sensor 155b for a predetermined time. Then, after measuring and calculating the distance between the eyeball of the subject and the near work target (the near work target distance) from the acquired image data, the true near work target distance is determined, and the store computer 100 Transmit (details will be described later).

  The user interface 153 is an input device such as a mouse or a keyboard. The processor 151 detects these operations by the optician staff and controls the operation of the near-work target distance measuring device 150.

  The monitor 154 is a display device for displaying an operation screen of the near-work target distance measuring device 150, an image captured by the camera 155a, and the like. The monitor 154 displays an image including the eyeball of the subject and the near work object, and a distance between them (close work target distance) by a near work target distance measurement program described later ( Details will be described later).

  The imaging unit 155 is a sensor for measuring the distance between the eyeball of the subject and the near-work object. The imaging unit 155 of the present embodiment captures an image including the subject's eyeball and the near-work object, maps the image in three dimensions, and determines the subject's eyeball and the near-work object from these three-dimensional information. For example, a known three-dimensional mapping apparatus or the like as described in JP-T-2009-511897 can be applied.

  The imaging unit 155 includes a camera 155a and a distance image sensor 155b. The camera 155a is a digital camera for imaging a subject and a near-work object, and the captured image specifies a pixel (pixel) corresponding to the eyeball of the subject and a pixel corresponding to the near-field object. To be used. The camera 155a is preferably used for color image shooting. However, if the pixel corresponding to the eyeball of the subject and the pixel corresponding to the near-work object can be specified, the camera 155a may be used for monochrome image shooting. Applicable.

  The distance image sensor 155 b captures a distance image including the subject and the near work object under the control of the processor 151, and outputs the image data to the processor 151. The distance image is a two-dimensional image in which each pixel constituting the image has information in the depth direction (that is, distance information of the subject). In the present embodiment, alignment is performed in advance so that each pixel of the image captured by the distance image sensor 155b can be associated with each pixel of the image captured by the camera 155a.

  The processor 151 processes the image data input from the camera 155a and the distance image sensor 155b, and generates three-dimensional coordinate data for the subject's eyeball and near-work object and for the subject included in the image. Then, the processor 151 generates three-dimensional coordinate data for each pixel based on the obtained depth information (distance image) of each pixel. The three-dimensional coordinate data is data in an XYZ coordinate system with the optical center of the distance image sensor 155b as the origin. In this embodiment, the horizontal direction of the distance image sensor 155b is the X axis and the vertical direction is the Y axis. The depth direction is defined as the Z axis.

  As described above, each pixel of the image captured by the camera 155a is aligned so as to be associated with each pixel of the image captured by the distance image sensor 155b. Therefore, when the three-dimensional coordinate data is generated as described above, it is possible to obtain the three-dimensional coordinates at the pixel by specifying each pixel of the image captured by the camera 155a. The processor 151 calculates the distance between the three-dimensional coordinate data of the pixel corresponding to the eyeball of the subject and the pixel corresponding to the near-work object specified by the near-work target distance measurement program described later. (Near work target distance) is obtained and transmitted to the store computer 100 (details will be described later).

[Near-work distance measurement program]
FIG. 4 is a flowchart illustrating a processing flow of the near work target distance measurement program executed by the processor 151 of the near work target distance measurement apparatus 150 according to the present embodiment. The processing of this program is started when there is an input to start measurement by operating the user interface 153 by the spectacle store staff. For convenience of explanation, the processing step of this program is abbreviated as “S” in the explanation and drawings in this specification.

  When the processing of this program is started, S11 is executed. In S11, the processor 151 controls the distance image sensor 155b to acquire distance image data of the subject and the near-work object. Next, the process proceeds to S12.

  In S12, coordinate conversion is performed on the distance image data obtained from the distance image sensor 155b (that is, distance information of each pixel) to generate three-dimensional coordinate data. Next, the process proceeds to S13.

  In S13, the processor 151 acquires image data (image data of an image including a subject and a near-work object) from the camera 155a, and proceeds to S14.

  In S14, the processor 151 outputs and displays the image acquired in S13 on the monitor 154, and proceeds to S15.

  In S15, the processor 151 specifies the position of the eyeball of the subject from the image data of the camera 155a acquired in S13. Specifically, the processor 151 first specifies a face area from the image. For example, a known technique introduced in Non-Patent Document 1 below can be used to specify the face area.

Paul Viola and Michel J. Jones: "Robust Real-Time Face Detection", International Journal of Computer Vision 57 (2), pp.137-154, (2004)

  Then, the processor 151 similarly extracts an image area corresponding to both eyes for the specified face area, and obtains the center pixel position (pixel position in the image of the camera 155a) for each image area. The pixel position (that is, the pixel position) is specified as the position of the eyeball of the subject. Next, the process proceeds to S16.

  In S16, the processor 151 confirms whether or not the position of the eyeball of the subject could be specified by the process of S15. For example, when the subject blinks or the like, and the position of the eyeball of the subject cannot be specified by the process of S15 (S16: NO), the process returns to S11, and S11 to S16 This process is repeatedly executed. On the other hand, if the position of the eyeball of the subject can be specified in S15 (S16: YES), the process proceeds to S17.

  In S17, the processor 151 specifies the position of the near work object from the image data of the camera 155a acquired in S13. Here, a predetermined marking (for example, a red circular seal) is applied in advance to the near-work object of the present embodiment. The processor 151 extracts an image area corresponding to the marking from the acquired image by template matching, and specifies the pixel position (that is, the pixel position) at the center of the image area as the position of the near-work object. Next, the process proceeds to S18. Note that the position of the near-work object is specified by the user interface 153 using the image area (pixel) where the near-work object is displayed while the eyeglass shop staff looks at the image of the camera 155a displayed on the monitor 154. It may be performed by specifying using. In this case, in the subsequent frames (that is, the new image acquired in S13), the object tracking is performed by using the feature amount such as the histogram of the pixel peripheral area designated by the user interface 153, so that The position can be specified.

  In S18, the processor 151 acquires the three-dimensional coordinate data of the pixel position (pixel position) of both eyes of the subject specified in S15 from the three-dimensional coordinate data generated in S12. Similarly, the processor 151 acquires three-dimensional coordinate data of the pixel position (pixel position) of the near-work object specified in S17 from the three-dimensional coordinate data generated in S12. Then, the processor 151 obtains the distance between each eyeball of the subject and the near work object from the 3D coordinate data of the both eyes of the subject and the 3D coordinate data of the near work object. The average value is stored in the memory 152 as a temporary near work target distance. In the configuration of the present embodiment, since the three-dimensional coordinate data on the back side of the near-work object is obtained in S17, when the near-work object has a thickness, the near process object is obtained by this process. The temporary distance for near work may be obtained by correcting the amount corresponding to the thickness of the object. Next, the process proceeds to S19.

  In S <b> 19, the processor 151 converts the temporary near work target distance obtained in S <b> 18 into character data, superimposes it on the image of the camera 155 a acquired in S <b> 13, and outputs it to the monitor 154. Thereby, the temporary near work target distance is displayed on the monitor 154 together with the image of the camera 155a. Next, the process proceeds to S20.

  In S20, the processor 151 determines whether images of the camera 155a and the distance image sensor 155b have been captured for a predetermined number of frames (for example, 18,000 frames). As described above, the near-work target distance measuring device 150 of the present embodiment is configured to measure an actual near-work target (i.e., a personal computer) in order to measure an accurate near-work target distance according to the usage purpose of the customer's glasses. And books) are used to find the near-work target distance. However, the environment at the eyeglass store is different from the environment at home, and it is also possible that the subject is excessively aware of measuring the near-distance target distance. It is considered that it takes time to get used to the measurement environment before using the device. Therefore, in the present embodiment, the images of the camera 155a and the distance image sensor 155b are acquired by the number of frames corresponding to at least the time required to get used to the measurement environment (for example, 10 minutes) and obtained by each frame. When the temporary near-work target distance becomes stable, this distance is set as the true near-work target distance (described later). When it is determined by S20 that the number of frames is less than the predetermined number (S20: NO), the process returns to S11, and S11 to S20 are repeatedly executed. On the other hand, if it is determined in S20 that a predetermined number of frames have been captured (S20: YES), the process proceeds to S21.

  In S21, the processor 151 analyzes the temporary near work target distance of each frame stored in S18. FIG. 5 is a graph showing the temporary near-work target distance of each frame stored in S18. As shown in FIG. 5, since the posture of the subject is not stable at the start of measurement, the temporary near-work target distance is not stable (the range of “A” in FIG. 5), but as the number of frames advances (that is, The amount of change becomes smaller (with the passage of time), and the temporary near-work target distance is stabilized at about 38 to 39 cm (range “B” in FIG. 5). The processor 151 analyzes the temporary near-work target distance of each frame stored in S18, and has a small change amount (variation) (for example, within ± 1 cm; hereinafter, this state is referred to as “steady state”). Is continued over a predetermined number of frames (for example, 1,800 frames or more), it is determined that the subject's posture is stable. Then, the processor 151 obtains an average value of the temporary near-work target distance classified into the steady state, and sets this average value as the true near-work target distance. If the steady state does not continue for a predetermined frame (for example, 1800 frames) during the measurement for a predetermined time (10 minutes, 18,000 frames), the measured near-work target distance is incremented by 1 cm, for example. The histogram is used as a histogram, and the closest measured distance for near work is set as the true distance for near work. The near work target distance measured most during the measurement indicates that the test subject has the highest probability of performing near work at the near work target distance. Next, the process proceeds to S22.

  In S22, the processor 151 transmits the true near-work target distance obtained in S21 to the storefront computer 100, and ends this program.

  As described above, the near-work target distance measuring device 150 of the present embodiment uses the actual near-work object (that is, a personal computer or a book) a plurality of temporary near-work target distances over a predetermined time. And monitoring the change over time of the temporary near work target distance. When the temporary near work target distance is in a stable state (that is, when the temporary near work target distance is in a steady state), the average value of the temporary near work target distance is set as the true near work target distance. Therefore, according to the near-work target distance measuring device 150 of the present embodiment, the (true) near-work target distance when the subject is used to the measurement environment and takes a relaxed posture can be accurately obtained. As described above, the near work target distance obtained by the near work target distance measuring apparatus 150 of the present embodiment is transmitted to the spectacle lens design computer 202 of the spectacle lens manufacturing factory 20 via the store computer 100. This is used for calculating the inset amount and the addition power of the progressive addition lens. The eyeglass lens design computer 202 determines the infeed amount and the near vision frequency based on the near work target distance obtained by the near work target distance measurement device 150 in the design of the progressive power lens, for example. The addition power and the addition power distribution are determined based on the near power and the far power (for example, power corresponding to a distance that can be regarded as infinity such as 5 m). Further, the spectacle lens design computer 202, for example, uses a semi-designed progressive-power lens (for example, a lens for which a near power is set at a specified near-work target distance (such as 40 cm)) and a near use amount. The frequency is corrected based on the near work target distance obtained by the near work target distance measuring device 150. The eyeglass lens design computer 202 corrects the addition power and addition distribution of the surface opposite to the semi-plane based on the corrected near power, thereby obtaining the progressive power lens of this design. Thus, according to the present embodiment, a spectacle lens in which the addition power and the addition distribution are accurately adjusted according to the purpose of use of the glasses of the subject can be obtained.

  The above is description of this embodiment, However, This invention is not limited to said structure, A various deformation | transformation is possible in the range of the technical idea of this invention. For example, in this embodiment, the near work target distance obtained by the near work target distance measuring device 150 is transmitted to the store computer 100 and is used by the store computer 100 to calculate the prescription value (addition power) of the lens. Although it is configured, the present invention is not limited to this configuration, and the calculation of the prescription value (add power) of the lens may be performed by the near-work target distance measuring device 150.

  Moreover, although the near work target distance measuring device 150 of the present embodiment is configured to capture the image by the distance image sensor 155b and generate the three-dimensional coordinate data, for example, the eyeball of the subject and the near work object are included. The position of the eyeball of the subject and the position of the near work object are determined from the pixel corresponding to the eyeball of the subject and the pixel corresponding to the near work object in the image. It can also be configured to be specified. In this case, for example, it is preferable to place an index of a predetermined size at a predetermined position, take an image so that the index is included in the image at the same time, and perform image processing on the captured image based on the index. According to such a configuration, the position of the eyeball of the subject and the position of the near-work object can be accurately measured even from an image from one camera, and the distance image sensor 155b is not necessary.

  The distance image sensor 155b of the present embodiment may be any device that can acquire a distance image. For example, the distance image sensor 155b may be replaced with a plurality of cameras that are the same as the camera 155a, and acquire a distance image by stereo viewing. In addition, the distance image sensor that acquires the distance image and the camera that acquires the image are not necessarily separate, and an integrated sensor may be used.

  Further, in the near-work target distance measuring device 150 of the present embodiment, the posture of the subject when the temporary near-work target distance change amount continues within a predetermined range over a predetermined number of frames. Calculate the average of the temporary near-work target distance, or if the posture is not stable, create a histogram of the measurement results, find the most measured near-work target distance, Although it was set as the near work target distance, it is not limited to this configuration. For example, the standard deviation is calculated for all the obtained temporary near work target distances, and the true value is calculated based on the result. It is also possible to set the near work target distance. Also, it is not always necessary to set the average of the temporary near-work target distance as the true near-work target distance, and the upper and lower limits of the temporary temporary near-work target distance in the steady state are set as the true near-work target distance. It is also possible to do.

  Further, in the near-work target distance measuring device 150 of the present embodiment, the image of the camera 155a and the distance image sensor 155b is configured to be captured by a predetermined number of frames. However, if it can be detected that the posture of the subject is stable. For example, the imaging with the camera 155a and the distance image sensor 155b may be stopped when the temporal change in the temporary near-work target distance falls within a predetermined range.

  In the present embodiment, the distance from the center of the region corresponding to the eyeball of the subject (the surface of the eyeball, more specifically, the apex of the cornea, for example) to the near work object is defined as the near work target distance. However, because eyeglass lenses are designed using an eyeball model that rotates around the eyeball rotation point, the eyeglass rotation point is not the distance from the center of the area corresponding to the eyeball to the nearwork object, but the eyeball rotation point is the near work object. It may be easier for spectacle lens designers to measure the distance to an object. Therefore, the eyeball rotation point may be calculated using the method described below, and the distance from the eyeball rotation point to the near work object may be set as the near work target distance.

Here, a method for calculating the eyeball rotation point will be described. Specifically, the processor 151 uses the known eyeball model to obtain the three-dimensional coordinate data (x _c ) of the pixel position (here, the corneal vertex) of the eyeball of the subject acquired in S18 of FIG. , Y _c , z _c ), the three-dimensional coordinates of the eyeball rotation point are calculated. For example, consider the case of using Gullstrand's model eye. In this case, the eyeball rotation point can be defined as being located 13 mm behind the apex of the cornea along the depth direction of the eyeball. Note that the center of the region corresponding to the eyeball of the subject and the corneal apex do not exactly match, but since the error is small, it is assumed here that they match.

  During imaging, the imaging unit 155 and the subject's head are not in principle facing each other. Here, “facing” refers to a state in which the direction of the coordinate system (coordinate axis) of the imaging unit 155 matches the direction of the coordinate system (coordinate axis) of the subject's head. The coordinate system of the imaging unit 155 is the coordinate system described above, the horizontal direction of the distance image sensor 155b is the X axis, the vertical direction of the distance image sensor 155b is the Y axis, and the depth direction of the distance image sensor 155b is the Z axis ( The value is defined as a value that increases toward the front from the imaging unit 155). Hereinafter, the coordinate system of the imaging unit 155 is referred to as a “camera coordinate system”. The coordinate system of the subject's head is a coordinate system whose origin is a predetermined position of the head (for example, the center position of the nose), and is hereinafter referred to as a “head coordinate system”. The head coordinate system is a coordinate in which the horizontal direction of the subject's head is the x-axis, the vertical direction of the head is the y-axis, and the depth direction of the head is the z-axis (a positive value toward the back of the head). It is a system.

Consider the case where the orientation of the camera coordinate system and the orientation of the head coordinate system do not match. In this case, when a coordinate value equivalent to 13 mm is added to the Z component with respect to the corneal vertex position coordinates (x _c , y _c , z _c ) in the camera coordinate system acquired in S18 of FIG. In the coordinate system, this coordinate value addition is decomposed into X component, Y component, and Z component. Therefore, it can be seen that the eyeball rotation point coordinates are not accurately calculated. In order to accurately calculate the eyeball rotation point coordinates, it is necessary to match the direction of the camera coordinate system with the direction of the head coordinate system. Therefore, the processor 151 estimates the position and posture of the subject's head based on the image captured by the imaging unit 155. For example, by using a known technique described in Non-Patent Document 2 (Gabriele Fanelli, Juergen Gall, and Luc Van Gool: “Real Time Head Pose Estimation with Random Regression Forests” (2011)), a photographed image by the imaging unit 155 is used. The position and posture of the subject's head can be estimated based on the above. The position is defined by three axes xyz, and the posture is defined by a roll angle, a yaw angle, and a pitch angle.

The processor 151 defines a head coordinate system based on the estimated position and posture of the subject's head. The processor 151 performs a predetermined coordinate transformation (the direction of the coordinate axis of the camera coordinate system and the direction of the coordinate axis of the head coordinate system are matched), whereby the corneal vertex position coordinates (x _c , y _{c in the} camera coordinate system are matched). , Z _c ) are converted into corneal apex position coordinates (x _h , y _h , z _h ) in the head coordinate system. As a result, the subject is in front of the imaging unit 155 in software processing.

The processor 151 adds a predetermined value α (a value corresponding to 13 mm in this case) to the Z component of the corneal apex position coordinates (x _h , y _h , z _h ) after the coordinate conversion, so that the eyeball rotation point coordinates (x _h , Y _h , z _h + α). The eyeball rotation point coordinates (x _h , y _h , z _h + α) obtained here are the eyeball rotation point coordinates in a certain frame and are provisional values. The default value α is not limited to a value equivalent to 13 mm. Strictly speaking, the distance between the corneal apex and the eyeball rotation point is not uniquely determined in consideration of various factors such as race, sex, age, visual acuity, and the like. Therefore, it is possible to set a more appropriate default value α for the subject by selecting an appropriate default value α (eyeball model) in consideration of these factors.

The processor 151 acquires provisional values of the above-mentioned eyeball rotation point coordinates (x _h , y _h , z _h + α) for a predetermined number of frames (a number of frames sufficient to obtain a statistical value). The processor 151 calculates a value obtained by averaging provisional values for a predetermined number of frames, and sets the calculated average value as a definite value of the eyeball rotation point coordinates (x _h , y _h , z _h + α). In this way, the eyeball rotation point coordinates (x _h , y _h , z _h + α) that are the starting point of the line of sight are obtained, and the eye rotation point coordinates are unchanged in the head coordinate system. Is available as For example, the eyeball rotation point coordinates obtained using the provisional values of the eyeball rotation point coordinates of the frames f0 to fn can be used as they are in the subsequent frame fn + 1. However, in this case, since the eyeball rotation point is a coordinate value in the head coordinate system, it is necessary to convert the near-work object coordinate that is the end point of the line of sight from the camera coordinate system to the head coordinate system.

DESCRIPTION OF SYMBOLS 1 Eyeglass lens manufacturing system 10 Eyeglass store 20 Eyeglass lens manufacturing factory 100 Shop front computer 150 Near work target distance measuring device 151 Processor 152 Memory 153 User interface 154 Monitor 155 Image pick-up part 155a Camera 155b Distance image sensor 200 Host computer 202 Eyeglass lens design computer 204 Eyeglass lens processing computer 206 Processing machine

Claims (8)

A near work target distance measuring device for measuring a near work target distance of a subject wearing spectacles,
An imaging device that simultaneously captures in one image the eyeball of the subject and the near-work object used by the subject wearing glasses during near-work work;
A first position for extracting a region corresponding to the eyeball of the subject or an eyeball rotation point from the image captured by the imaging device and specifying the position of the eyeball of the subject on the image as an eyeball position Specific means,
A second position specifying means for extracting a region corresponding to the near work object from the image picked up by the imaging device, and specifying a position of the near work object on the image as an object position;
Distance calculating means for calculating a distance between the eyeball position and the object position as a temporary near-work target distance;
The imaging device captures the image at predetermined time intervals,
The near distance target distance measuring device, wherein the distance calculating means obtains a true near distance target distance based on the temporary near distance target distance calculated for each of the images.   The distance calculating means obtains a temporal change amount of the temporary near work target distance, and when the change amount is within a predetermined range continuously for a predetermined time, the temporary near business within the predetermined time The near work target distance measuring device according to claim 1, wherein an average value is obtained for the target distance, and the average value is used as the true near work target distance.   The distance calculating means obtains a temporal change amount of the temporary near-work target distance, and when the change amount does not fall within a predetermined range continuously for the first time, the second time The near work target distance measuring device according to claim 1, wherein a distance calculated most among the temporary near work target distances is set as the true near work target distance. A distance image sensor that simultaneously captures the eyeball of the subject and the near-work object to obtain a distance image;
The distance image sensor generates three-dimensional coordinate data of the subject's eyeball and the near work object based on the distance image,
The distance calculating means calculates the temporary near-work target distance based on three-dimensional coordinate data corresponding to the eyeball position and three-dimensional coordinate data corresponding to the object position. Alternatively, the near-work target distance measuring device according to claim 2.   The near work according to claim 3, wherein a correspondence relationship between each pixel of the image captured by the imaging device and each pixel of the distance image acquired by the distance image sensor is defined in advance. Target distance measuring device.   The near-field target distance measuring device according to claim 1, wherein the imaging device captures the image from a position where the subject's eyeball and near-field object can be simultaneously imaged. The step of acquiring the true near-work target distance from the near-work target distance measuring device according to any one of claims 1 to 5,
Based on the acquired true near-work target distance, setting the amount of eyeglass lens inset and power addition,
A spectacle lens manufacturing process for manufacturing a spectacle lens in which the inset amount and the addition power are set;
Of eyeglass lenses including The near-work target distance measuring device according to any one of claims 1 to 5,
An ordering-side terminal that sets the inset amount and the addition power of the spectacle lens based on the true near-work target distance, and transmits predetermined prescription information including the addition power as order data;
Designing a spectacle lens suitable for the prescription by receiving the order data, and a design side terminal for transmitting the spectacle lens design data;
A processing-side terminal that receives the design data and processes the spectacle lens;
An eyeglass lens manufacturing system comprising:

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