JP6048186B2 - VISION DETERMINING DEVICE, VEHICLE DISPLAY CONTROL DEVICE, AND PROGRAM - Google Patents

Description

  The present invention relates to a visual acuity determination device, a vehicle display control device, and a program.

  For example, in Non-Patent Document 1, a low band pass filter that passes a low frequency band is applied to one of two different images, and a high band that passes a high frequency band to the other image. A method of applying a pass filter and synthesizing images after applying each filter is disclosed. Such a composite image is composed, for example, when viewed from a distance and when viewed from near, or when the composite image is viewed with a small size and when the composite image is viewed with a large size. It has the feature of appearing as one of the original two images.

Hybrid images: GIGGRAPH'06 ACM SIGGRAPH 2006 Papers Pages 527-532

  However, although development of applied technology using the above technology has not progressed, the present inventor has found that the above technology can be used for visual acuity determination.

  The present invention has been made in view of the above points, and provides a visual acuity determination device, a vehicle display control device, and a program capable of determining visual acuity using a composite image obtained by combining two images. For the purpose.

The visual acuity determination device according to the first aspect of the present invention is:
A device for determining visual acuity for determining the visual acuity of a subject,
Presenting means for presenting to the subject a composite image of a first image having a frequency spectrum whose main frequency band is a low frequency band and a second image having a frequency spectrum whose main band is a high frequency band. And
The composite image is recognized as either the first image or the second image according to the visual acuity of the subject who is a predetermined distance away from the composite image presented by the presenting means. Is a possible image,
It is characterized by that.

A vehicle display control device according to a second aspect of the present invention provides:
The eyesight determination device according to the first aspect of the present invention is included.

The program according to the third aspect of the present invention is:
In the computer for judging the eyesight of the subject,
Generating a composite image of a first image having a frequency spectrum whose main band is a low frequency band and a second image having a frequency spectrum whose main band is a high frequency band;
A presentation step of displaying the composite image generated by the generation step on a predetermined display unit and presenting the composite image to the target person;
The composite image is recognized as either the first image or the second image according to the visual acuity of the subject who is a predetermined distance away from the composite image presented in the presenting step. Is a possible image,
It is characterized by that.

  According to the present invention, it is possible to determine visual acuity using a composite image obtained by combining two images.

It is a figure which shows a vehicle. It is a figure which shows the structure of the display control apparatus for vehicles. It is a figure which shows the original image and synthetic | combination image which concern on Embodiment 1. FIG. It is a flowchart of a visual acuity determination process. It is a flowchart of a setting process. It is a flowchart of an image composition process. It is a figure which shows a state when an adult male hold | maintains a driving posture. It is a figure which shows the reference frequency table which concerns on Embodiment 1. FIG. It is a figure which shows the synthesized image which synthesize | combined the original image showing a person's face. It is a figure which shows the selection screen for the visual acuity determination which concerns on Embodiment 1. FIG. It is a figure which shows the original image and synthetic | combination image which concern on Embodiment 2. FIG. It is a figure which shows the reference frequency table which concerns on Embodiment 2. FIG. It is a figure which shows the selection screen for the visual acuity determination which concerns on Embodiment 2. FIG. (A)-(c) is a figure which shows the original image and synthetic | combination image.

(Embodiment 1)
Hereinafter, a vehicle display control apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.
The vehicle display control device 100 is mounted on the vehicle 1 shown in FIG. 1 and has a function as a vehicle meter, and further has a function for determining a visual acuity that determines the visual acuity of a user (driver). Yes. However, when determining visual acuity, it is common to change the size of the character or figure for visual acuity determination (for example, Landolt ring) according to the visual acuity to be determined or the distance from the character or graphic to the user. The control device 100 can determine the visual acuity without changing the size of characters and figures.
Hereinafter, the configuration of the vehicle display control apparatus 100 will be described.

  As shown in FIG. 2, the vehicle display control apparatus 100 includes an operation unit 10, a display unit 20, a storage unit 30, and a control unit 40, and is mounted on the vehicle 1.

  The operation unit 10 includes a touch panel, operation switches, and the like, and is disposed on the steering 2 (see FIG. 1) of the vehicle 1. The steering 2 is a part of the steering device of the vehicle 1 and includes a main body 2a (a spoke connected to the steering shaft of the vehicle 1) and a steering wheel 2b attached to the main body 2a. . The operation unit 10 outputs operation information indicating the content of the user's input operation to the control unit 40.

  The display unit 20 includes an LCD (Liquid Crystal Display), an OELD (Organic Electro Luminescence Display), and the like, and is disposed facing the front of the vehicle display control device 100. The display unit 20 displays an image represented by the image signal supplied from the control unit 40 to the driver. For example, the display unit 20 is an image for determining visual acuity used for determining visual acuity, an image representing vehicle state information (vehicle speed, engine speed, etc.) (an image of a pointer-type instrument, a digital instrument image, etc.) ) Is displayed.

  The image for visual acuity determination is based on the frequency spectrum of the first image (for example, obtained by performing discrete Fourier transform on image data), and the frequency spectrum of the second image. It is a composite image (hybrid image) of an image from which high frequency components have been extracted. Here, why the visual acuity can be determined using the composite image will be described.

  Of the frequency spectrum of the image, the low frequency component represents a portion with a small change in gray value, and the high frequency component represents a portion with a large change in gray value. For example, since a background image of one color or an out-of-focus image has little change in gray value, these images are images of a frequency spectrum whose main component is a low frequency component. For example, since an image with a clear outline of a subject or an image with a fine picture has many changes in gray value, such an image is an image of a frequency spectrum whose main component is a high frequency component. Generally, the closer a person sees an image, the clearer the outline and the like, but the farther the image is, the more blurred the outline and the other parts become visible. That is, when looking at an image mainly composed of high frequency components, it can be seen well from near, and when looking at an image mainly composed of low frequency components, it can be seen well from a distance. For this reason, when a human sees a composite image close, the composite image appears as a second image mainly composed of high-frequency components (exactly, for example, a subject reflected in the second image becomes a composite image). When the composite image is viewed from a distance, the composite image appears as a first image mainly including low-frequency components (exactly, for example, a subject reflected in the first image is a composite image) Appears to appear).

  The inventor of the present application has found that visual acuity can be determined using such a composite image. Specifically, when the composite image is shown to a human being a predetermined distance away, it is found that the appearance of the composite image differs depending on the human eyesight (whether it looks like the first image or the second image). It was. That is, the present inventors have found that the user's visual acuity can be determined depending on whether the user sees the composite image as the first image or the second image. Furthermore, even if the distance between the user and the composite image is not constant, even if the distance changes by changing the band of the low frequency component and high frequency component to be extracted according to the distance, It has also been found that the user's visual acuity can be determined. This embodiment uses such a thing.

  An example of the composite image is shown in FIG. The composite image 4 in FIG. 3 includes an image obtained by extracting a low frequency component having a peak at a reference low frequency (a reference frequency when a low frequency component is extracted) from the frequency spectrum of the image 4-1, and an image 4- 2 is a composite image of an image obtained by extracting a high frequency component having a peak at a reference high frequency (a frequency used as a reference when extracting a high frequency component) from the frequency spectrum of 2. The reference low frequency is a frequency lower than the reference high frequency.

  The composite image 4 is visually recognized as an image 4-2 (an image representing Hiragana “Nu”) if a user at a predetermined distance from the composite image 4 has a predetermined visual acuity or more, and is less than the predetermined visual acuity. It has a feature of visually recognizing that it is an image 4-1 (an image representing the hiragana “me”). That is, when a user who is away by a predetermined distance visually recognizes that the composite image is the image 4-2 (when the hiragana “Nu” is seen), it can be determined that the user's visual acuity is equal to or greater than the predetermined visual acuity. Can be determined that the user's visual acuity is less than the predetermined visual acuity. In addition, when the predetermined distance changes, a composite image is generated using the same image even if the predetermined distance changes by changing a reference low frequency and / or a reference high frequency, and the determination The same judgment can be made.

  The storage unit 30 includes a storage device such as a flash memory and a hard disk, and stores a program for executing a visual acuity determination process, which will be described later, various tables, various data, and the like.

  The control unit 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a basic operation program, a RAM (Random Access Memory) that serves as a work area, and the like, according to programs stored in the ROM, the storage unit 30, and the like. Various processes are executed. For example, the control unit 40 executes a visual acuity determination process described later according to the visual acuity determination program. In addition, the control unit 40 operates according to the visual acuity determination program, so that a distance acquisition unit 41, a low frequency component extraction unit 42, a high frequency component extraction unit 43, a synthesis unit 44, a display control unit 45, and a visual acuity determination unit 46 are obtained. It functions (the processes performed by these units will be described later). Note that at least a part of the control unit 40 may be configured by various dedicated circuits such as an ASIC (Application Specific Integrated Circuit).

  Next, the operation of the vehicle display control apparatus 100 having such a configuration will be described with reference to the flowcharts of FIGS.

  The control unit 40 displays a menu screen on the display unit 20 when the vehicle display control device 100 is powered on. In this menu screen, a plurality of selection items including selection items “setting” and “sight determination” are displayed. The user operates the operation unit 10 to select one of a plurality of selection items.

  When the control unit 40 determines that the user has selected one of the selection items “setting” and “visual acuity determination” based on the operation information from the operation unit 10, the control unit 40 executes a visual acuity determination process.

  As illustrated in FIG. 4, the control unit 40 determines that the item selected as the trigger for starting the visual acuity determination process based on the operation information from the operation unit 10 is “setting” and “visual acuity determination” among “visual acuity determination”. (Step S100), if “sight determination” is not selected (step S100; No), that is, if “setting” is selected, a setting process is executed. (Step S200).

  In the setting process (see FIG. 5), the display control unit 45 of the control unit 40 displays a setting method selection screen on the display unit 20 (step S201). On the setting method selection screen, selection items “default value use” and “height input” are displayed. The user operates the operation unit 10 to select either the selection item “use default value” or “height input”.

  The display control unit 45 determines whether or not the user has selected the selection item “enter height” based on the operation information from the operation unit 10 (step S202), and when “enter height” is selected (step S202). S202; Yes), a height input screen for prompting the user to input height is displayed on the display unit 20 (step S203). The user inputs the height using the operation unit 10.

  On the other hand, in step S202, the display control unit 45 determines that “enter height” is not selected (step S202; No), that is, “use default value” is selected based on the operation information from the operation unit 10. If it is determined that a gender is input, a gender input screen for gender input is displayed on the display unit 20 (step S205). The user inputs gender using the operation unit 10.

  When the gender is input, the distance acquisition unit 41 of the control unit 40 refers to the height information table (stored in the storage unit 30) in which the gender and the height are associated with each other, and the operation information from the operation unit 10 is displayed. Based on (that is, based on the input gender), the height (default height value) associated with the user's gender is read from the height information table (step S206). The height associated with the sex in the height information table is the average height of men and women in Japan.

  When the height is input after the height input screen is displayed in step S203, or when the height is read in step S206, the distance acquisition unit 41 of the control unit 40 reads from the height or height information table input to the operation unit 10. Based on the read height, a predetermined distance from the composite image to the user's eyes, that is, a visual acuity determination distance is acquired (step S204).

Hereinafter, a method for obtaining the visual acuity determination distance will be described.
Based on an eye point (eye position) when an adult male defined by 3DM-JM50 (three-dimensional sitting human model for measuring vehicle interior dimensions) holds an average driving posture in the vehicle 1, a display unit The distance from 20 to the eye point (sight determination distance for 3DM-JM50) is measured. The measured distance and the height data of the 3DM-JM 50 used for the measurement are stored in the storage unit 30 in advance.
The distance acquisition unit 41 is a height ratio between the height input from the operation unit 10 or the height read from the height information table (also referred to as the user's height) and the height of the 3DM-JM 50 (stored in the storage unit 30). First, for example, the height of 3DM-JM50 is the denominator. The storage unit 30 includes a height ratio (1.1 to 1.2, etc., having a range of values), and a distance from the eye point P of the user 3 to the composite image (sight determination distance). Assume that an associated table (relationship between height ratio and distance may be measured in advance) is stored. The distance acquisition unit 41 refers to such a table and acquires the visual acuity determination distance L associated with the height ratio obtained above.

The distance acquisition unit 41 corrects the distance L based on the seat slide amount S and the seat back angle A when the user 3 actually holds the driving posture in order to calculate a more accurate distance L. Also good.
For example, the vehicle seat illustrated in FIG. 7 includes various sensors, and the distance acquisition unit 41 can receive the seat slide amount (seat slide amount S) and the seat back angle A detected by the various sensors. The storage unit 30 includes a seat slide amount S (having a width for the value), a seat back angle A (having a width for the value), and a correction value for the visual acuity determination distance L. Assume that an associated table (the three relationships may be measured in advance) is stored. The distance acquisition unit 41 refers to such a table, acquires the correction value associated with the seat slide amount S and the seat back angle A received from the sensor, and the correction acquired for the visual acuity determination distance L acquired above. The corrected visual acuity determination distance L is acquired by adding (or subtracting) the value.

  Next, the distance acquisition unit 41 stores the acquired visual acuity determination distance in the storage unit 30 (step S207), and ends the setting process.

  Returning to FIG. 4, after the setting process is completed, the control unit 40 executes an image composition process (step S300). The control unit 40 also executes the image composition process (see FIG. 6) even when “sight determination” is selected (step S100; Yes) (step S300).

  In the image synthesis process, for example, two images are synthesized, and the above-described synthesized image is generated. Here, one image is an image A (an image that is a source of a composite image, hereinafter referred to as an original image A as appropriate), and the other image is an image B (an image that is a source of a composite image, It is referred to as an original image B as appropriate). The image data of these images is stored in advance in the storage unit 30 and used. In the image synthesis process, the low frequency component extraction unit 42 performs discrete Fourier transform on the original image A for the density value of each pixel specified by the image data of the original image A, and the frequency spectrum (frequency component) of the original image A is obtained. get. Moreover, the high frequency component extraction part 43 carries out a discrete Fourier transform about the density | concentration value of each pixel specified by the image data of the original image B about the original image B, and acquires the frequency spectrum of the original image B (step S301).

  Next, the low frequency component extraction part 42 performs the process of step S302. The low frequency component extraction unit 42 refers to the reference frequency table 31 stored in advance in the storage unit 30 in step S302. As shown in FIG. 8, the reference frequency table 31 holds the visual acuity determination distance, the reference low frequency, and the reference high frequency in association with each other. In the reference frequency table 31, for each of the visual acuity determination distances that are the distance between the composite image 4 and the user, a reference low frequency for generating a composite image that can appropriately determine the visual acuity at the corresponding visual acuity determination distance. , And a reference high frequency. That is, when the composite image is generated using the reference low frequency associated with the first distance and the reference high frequency, the reference low frequency and the reference high frequency are used. When the synthesized image is visually recognized as the original image B by performing visual acuity determination (the visual acuity determination distance is the first distance) using the generated composite image (for example, when the hiragana “Nu” in FIG. 3 is seen) ), It can be determined that the user's visual acuity is greater than or equal to the predetermined visual acuity, and when the synthesized image is visually recognized as the original image A (for example, when the hiragana “Me” in FIG. 3 is visible), the user's visual acuity is It can be determined that the visual acuity is less than the predetermined visual acuity. Similarly, when the composite image is generated using the reference low frequency and the reference high frequency associated with the second distance as the visual acuity determination distance, the reference low frequency and the reference high frequency are used. By performing visual acuity determination (the visual acuity determination distance is the second distance) using the generated composite image, the composite image is visually recognized as the original image B (for example, Hiragana “Nu” in FIG. 3 is visible) In the case), it can be determined that the user's visual acuity is equal to or greater than the predetermined visual acuity, and when the synthesized image is visually recognized as the original image A (for example, when the hiragana “Me” in FIG. 3 is seen), It can be determined that the visual acuity is less than the predetermined visual acuity.

  Further, in step S302, the low frequency component extraction unit 42 specifies a visual acuity determination distance that matches the visual acuity determination distance recorded in the storage unit 30 in step S207, among the visual acuity determination distances included in the reference frequency table 31. Next, the low frequency component extraction unit 42 acquires a reference low frequency associated with the specified visual acuity determination distance. The storage unit 30 stores, for each reference low frequency in the reference frequency table 31, a plurality of low band pass filters (here, a band pass filter that allows low frequency components to pass) having the reference low frequency as a peak. Here, a low band pass filter having a peak at the reference low frequency L1 (Hz), a low band pass filter having a peak at the reference low frequency L2 (Hz), a low band pass filter having a peak at the reference low frequency L3 (Hz), etc. are stored. Has been. Further, in step S302, the low frequency component extraction unit 42 acquires a low band pass filter whose peak is the reference low frequency specified above from the storage unit 30, and applies the acquired low band pass filter to the frequency spectrum of the original image A. Thus, a low frequency component having a reference low frequency as a peak is extracted from the frequency spectrum of the original image A.

  After step S302, in step S303, the high frequency component extraction unit 43 refers to the reference frequency table 31 and acquires the reference high frequency associated with the eyesight determination distance specified above. The storage unit 30 stores a plurality of high-band pass filters (herein, band-pass filters that allow high-frequency components to pass) having a peak at the reference high frequency for each reference high frequency in the reference frequency table 31. Has been. Here, a high band pass filter having a peak at the reference high frequency H1 (Hz), a high band pass filter having a peak at the reference high frequency H2 (Hz), and a high band pass filter having a peak at the reference high frequency H3 (Hz). Etc. are stored. Further, in step S303, the high frequency component extraction unit 43 acquires a high band pass filter whose peak is the reference high frequency specified above from the storage unit 30, and uses the acquired high band pass filter as the frequency spectrum of the original image B. To extract a high frequency component having a reference high frequency as a peak from the frequency spectrum of the original image B.

  Next, the synthesizing unit 44 synthesizes the low frequency component extracted by the low frequency component extracting unit 42 and the high frequency component extracted by the high frequency component extracting unit 43 (the frequency spectra may be added together). Then, the synthesized frequency component (spectrum) is subjected to inverse discrete Fourier transform to generate a synthesized image (step S304), and the image synthesis process is terminated.

The content of the image composition process is expressed by the following formula.
Composite image H = I1 · G1 + I2 · (1−G2) (1)
Here, I1 is the original image A. I2 is the original image B. G1 and G2 are low band pass filters in which the pixel density value Gain is halved.
The low-band pass filter may be any appropriate filter such as a Gaussian filter, a filter using a moving average method, or a median filter.

  Further, referring to FIG. 9, how the images are combined will be described. First, an image 8A is prepared as the original image A, and an image 8B is prepared as the original image B. A low frequency component is extracted for the image 8A, and a high frequency component is extracted for the image 8B. A frequency spectrum image representing a low frequency component extracted from the frequency spectrum of the image 8A is an image 8A '. In the frequency spectrum image, the center is a direct current component, each frequency component is distributed radially from the center, and the higher the distance from the center, the higher the frequency component. A frequency spectrum image representing a high frequency component extracted from the frequency spectrum of the image 8B is an image 8B '. Next, the extracted low frequency component and the extracted high frequency component are added together. The image 8C is a frequency spectrum image representing the added frequency spectrum. Thereafter, the inverse frequency Fourier transform is performed on the added frequency spectrum to obtain image data of the composite image 8.

  Returning to FIG. 4, the display control unit 45 displays a selection screen for eyesight determination on the display unit 20 (step S101). As shown in FIG. 10, on the selection screen 91, “What is displayed on the image for eyesight determination? When the same image displayed on image A is displayed,“ image A ”is displayed. Select the button that says If the same image displayed on image B is displayed, select the button labeled “Image B”. Is displayed.

  The composite image 4 (eyesight determination image) is displayed on the left of the center of the selection screen 91, and the image 4-1 that is the original image A and the image 4-2 that is the original image B are displayed on the right. Has been. In addition, a selection button 4-1 ′ on which characters “image A” are displayed is displayed below the image 4-1, and characters “image B” are displayed below the image 4-2. The selected button 4-2 ′ is displayed.

  A user who is separated from the composite image by a predetermined distance (the length determined as the visual acuity determination distance specified above) follows the message displayed on the selection screen 91, and the character represented by the composite image 4 is the image 4-1. It is confirmed whether it looks like the hiragana “Me” represented by or hiragana “nu” represented by the image 4-2. Further, the user selects either the selection button 4-1 'or the selection button 4-2' according to the confirmation result. When the user's visual acuity is less than a predetermined visual acuity (for example, lower than 0.7 required for driving), the user can see the character displayed in the composite image 4 as a hiragana “M”, and therefore the selection button 4 -1 'is selected. On the other hand, when the user's visual acuity is equal to or higher than a predetermined visual acuity (for example, 0.7 or higher necessary for driving), the user sees the character displayed in the composite image as Hiragana “Nu”. Select 2 '.

  The visual acuity determination unit 46 determines whether or not the selection button has been selected by the user based on the operation information from the operation unit 10 (step S102). If there is no user selection (step S102; No), the visual acuity determination unit 46 performs the process of step 102 again.

  When there is a user selection (step S102; Yes), in step S103, the visual acuity determination unit 46 determines the user's visual acuity, for example, by determining which selection button the user has selected. For example, when the selection button 4-1 'is selected, the visual acuity determination unit 46 determines that the visual acuity of the user is less than 0.7. When the selection button 4-2 'is pressed, the visual acuity determination unit 46 determines that the user's visual acuity is 0.7 or more. In step S103, the display control unit 45 displays the visual acuity determination result by the visual acuity determination unit 46 on the display unit 20 (step S103).

  After displaying the visual acuity determination result, the display control unit 45 displays a menu screen on the display unit 20 and ends the visual acuity determination process.

  According to the present embodiment, the vehicle display control apparatus 100 extracts a frequency component having a peak corresponding to the distance from the synthesized image for visual acuity determination to the user from the synthesized image, and determines a predetermined visual acuity. To generate a composite image. Thereby, the display control apparatus 100 for vehicles can determine predetermined visual acuity at predetermined distance, without changing the magnitude | size of the character and figure which a synthesized image represents. In particular, conventionally, when determining high visual acuity (for example, whether or not 1.5), characters and figures (for example, Landolt rings) must be reduced. In such a case, if the pixels of the display device that displays the characters and figures are not fine, the characters and figures cannot be displayed finely, but in this embodiment, the eyesight can be determined without changing the size of the characters and figures. It is not necessary to make the pixels of the display device fine, and the visual acuity can be determined at low cost.

(Embodiment 2)
In the first embodiment, the visual acuity is determined by generating one composite image using one set of the reference low frequency and the reference high frequency. However, in the second embodiment, the original image A and the original image B each include a plurality of images. It divides | segments into an area | region, A synthetic | combination image is produced | generated using the reference | standard low frequency and reference | standard high frequency from which a peak differs about each area | region, and it shows for visual acuity determination. Hereinafter, the second embodiment will be described, but the description of the overlapping parts with the first embodiment (the configuration of the vehicle display control device 100) will be appropriately omitted.

  In the second embodiment, the contents of the image composition processing and the contents of the reference frequency table 31 are mainly different from those in the first embodiment, and therefore, description will be made mainly on these. In addition, it cannot be overemphasized that the aspect of Embodiment 1 can be changed suitably with the following description.

  The flowchart of the image composition process in the second embodiment is the same as the flowchart of the image composition process in the first embodiment (see FIG. 6). In the following, the original images that are the basis of the composite image are referred to as an image 11 and an image 12 shown in FIG.

  When the image synthesis processing is started, the low frequency component extraction unit 42 divides the image 11 into a plurality of regions (divided regions 11-1 to 11-6) as shown in FIG. For each divided region (divided region), the density value of each pixel specified by the image data of the divided region is subjected to discrete Fourier transform to obtain a frequency spectrum. The high-frequency component extraction unit 43 divides the image 12 into a plurality of regions (divided regions 12-1 to 12-6), and each divided region (divided region) is specified by the image data of the divided region. The density value of each pixel is discrete Fourier transformed to obtain a frequency spectrum (step S301).

  Next, the low frequency component extraction part 42 performs the process of step S302. The low frequency component extraction unit 42 refers to the reference frequency table 31 stored in advance in the storage unit 30 in step S302. As shown in FIG. 12, the reference frequency table 31 holds a plurality of reference low frequencies in association with one visual acuity determination distance. For example, for the visual acuity determination distance “41 cm”, a reference low frequency L11 (Hz) corresponding to visual acuity 0.2, a reference low frequency L21 (Hz) corresponding to visual acuity 0.4, and a reference corresponding to visual acuity 0.6. A reference low frequency such as the low frequency L31 (Hz) is associated. Further, the reference frequency table 31 holds a plurality of reference high frequencies in association with one visual acuity determination distance. For example, for a visual acuity determination distance “41 cm”, a reference high frequency H11 (Hz) corresponding to visual acuity 0.2, a reference high frequency H21 (Hz) corresponding to visual acuity 0.4, and a reference corresponding to visual acuity 0.6. A reference high frequency such as a high frequency H31 (Hz) is associated. A set of reference low frequency and reference high frequency associated with the same predetermined visual acuity is used when the composite image is generated using these frequencies and the user views the composite image at the visual acuity determination distance associated with these frequencies. If the composite image looks like the image 12, it can be determined that the visual acuity is higher than the predetermined visual acuity, and if the composite image looks like the image 11, the frequency can be determined to be less than the predetermined visual acuity. That's fine. For example, the reference low frequency L11 (Hz) and the reference high frequency H11 (Hz) associated with the visual acuity 0.2 are the visual acuity determinations associated with these frequencies when a synthesized image is generated using these frequencies. When the user views the composite image at a distance “41 cm”, if the user has a visual acuity of 0.2 or more, the composite image looks like the original image B, and if the user has a visual acuity of less than 0.2, the composite image is the original image A. Any frequency can be used. In this embodiment, a plurality of the predetermined visual acuities are prepared, and a group consisting of a reference low frequency and a reference high frequency for each of these (reference low frequency and reference high frequency, aligned in a horizontal row of the reference frequency table 31 in FIG. 12). Group), and this group is prepared for each eyesight determination distance.

  The low frequency component extraction unit 42 specifies a visual acuity determination distance that matches the visual acuity determination distance stored in the storage unit 30 in step S207 among the visual acuity determination distances included in the reference low frequency table 31. Here, the specified visual acuity determination distance is “41 cm”. Next, the low frequency component extraction unit 42 acquires a plurality of reference low frequencies (reference low frequencies L11 (Hz) to L61 (Hz)) associated with the specified visual acuity determination distance. The storage unit 30 stores a plurality of low-band pass filters having a peak at the reference low frequency for each of the reference low frequencies in the reference frequency table 31. For example, a low band pass filter having a peak at the reference low frequency L11 (Hz), a low band pass filter having a peak at the reference low frequency L21 (Hz), a low band pass filter having a peak at the reference low frequency L31 (Hz), and the like are stored. ing.

  Further, in step S <b> 302, the low frequency component extraction unit 42 acquires a low band pass filter having the reference low frequency acquired as a peak from the storage unit 30. A plurality of low band pass filters are acquired for each of the reference low frequencies acquired above. Moreover, the low frequency component extraction part 42 applies each acquired low band pass filter to the frequency spectrum of the image in each of the division area 11-1 to 11-6 on a one-to-one basis. For example, the low frequency component extraction unit 42 applies a low band pass filter having a peak at the reference low frequency L11 (Hz) to the frequency spectrum of the image in the divided region 11-1, and sets the reference low frequency L21 (Hz) as a peak. The low band pass filter is applied to the frequency spectrum of the image in the divided region 11-2. Further, the low frequency component extraction unit 42 applies a low band pass filter having a peak at the reference low frequency L31 (Hz) to the frequency spectrum of the image in the divided region 11-3, and sets the reference low frequency L41 (Hz) as a peak. The low-band pass filter is applied to the frequency spectrum of the image in the divided region 11-4. In this way, the low frequency component extraction unit 42 obtains low frequency components having the reference low frequencies L11 (Hz) to L61 (Hz) as peaks from the frequency spectra of the images in the divided regions 11-1 to 11-6, respectively. Extract.

  After step S302, in step S303, the high frequency component extraction unit 43 acquires from the storage unit 30 a high-band pass filter having a peak at the reference high frequency acquired above. A plurality of high band pass filters are acquired for each of the reference high frequencies acquired above. Moreover, the high frequency component extraction part 43 applies each acquired high band pass filter to the frequency spectrum of the image in each divided area 12-1 to 12-6 on a one-to-one basis. For example, the high frequency component extraction unit 43 applies a high band pass filter having a peak at the reference high frequency H11 (Hz) to the frequency spectrum of the image in the divided region 12-1, and peaks the reference high frequency H21 (Hz). Is applied to the frequency spectrum of the image in the divided region 12-2. Further, the high frequency component extraction unit 43 applies a high bandpass filter having a peak at the reference high frequency H31 (Hz) to the frequency spectrum of the image in the divided region 12-3, and peaks the reference high frequency H41 (Hz). Is applied to the frequency spectrum of the image in the divided region 12-4. Thus, the high frequency component extraction unit 43 obtains high frequency components having the reference high frequencies H11 (Hz) to H61 (Hz) as peaks from the frequency spectra of the images in the divided regions 12-1 to 12-6, respectively. Extract.

  Next, the synthesis unit 44 synthesizes each of the low frequency components extracted by the low frequency component extraction unit 42 and each of the high frequency components extracted by the high frequency component extraction unit 43 on a one-to-one basis (adds the frequency spectra to each other). In other words, each synthesized frequency component (spectrum) is subjected to inverse discrete Fourier transform to generate a synthesized image. For example, as illustrated in FIG. 11, the combining unit 44 combines the low-frequency component of the image in the divided region 11-1 and the high-frequency component of the image in the divided region 12-1, and reverses the combined frequency component. Discrete Fourier transform is performed to generate a composite image 13-1. The synthesizing unit 44 synthesizes the low-frequency component of the image in the divided region 11-2 and the high-frequency component of the image in the divided region 12-2, and performs inverse discrete Fourier transform on the synthesized frequency component to obtain a synthesized image. 13-2 is generated. As described above, the synthesis unit 44 synthesizes the low-frequency components in each of the divided regions 11-1 to 11-6 and the high-frequency components in each of the divided regions 12-1 to 12-6 on a one-to-one basis. 13-1 to 13-6 are generated.

  Next, the synthesizing unit 44 arranges the generated synthesized images 13-1 to 13-6 to generate one synthesized image 13. Here, as shown in FIG. 11, the combining unit 44 sets the combined image 13-1 as the left end (in order to correspond the divided regions 11-1 to 11-6 in the image 11). 13-3 are arranged on the right side so as to be adjacent to each other, and one composite image 13 is generated. Note that the arrangement of the composite images 13-1 to 13-6 is arbitrary. For example, the composite images 13-1 to 13-6 may be arranged so as to be separated from each other by a predetermined interval or may be arranged so as to partially overlap. When the composite image 13 to be displayed on the selection screen for visual acuity determination is generated, the composition unit 44 ends the image composition processing. Here, in the image synthesis, the image synthesis is performed while maintaining the positional relationship between the divided areas of the image 11 and the divided areas of the image 12. For example, the synthesized image is adjacent to the synthesized image 13-1. The image may be synthesized by changing the positional relationship, for example, by arranging 13-6.

  Subsequently, as illustrated in FIG. 4, the display control unit 45 displays a selection screen for visual acuity determination on the display unit 20 (step S <b> 101). As shown in FIG. 13, the selection screen 91 displays “Select the button below the image where the pattern disappears when viewing the images in order from the left. Select the button that says "I can't see it at all". Is displayed.

  In the center of the selection screen 91, the composite image 13 generated in step S304 is displayed, and a selection button 13- is provided below each of the divided areas 13-1 to 13-6 constituting the composite image 13. Each of 1 ′ to 13-6 ′ is displayed in a one-to-one relationship.

  At the bottom of the selection screen 91, a selection button 13-7 ′ displaying characters “I cannot see at all” is displayed.

  A user who is separated from the composite image by a predetermined distance (the visual acuity determination distance “41 cm” specified in step 207) looks at the composite images 13-1 to 13-6 in order from the left according to the message displayed on the selection screen 91. . When there is an image whose pattern cannot be seen, the user presses a selection button below the image. For example, the user looks at the composite images 13-1 to 13-6 in order from the left, and selects the selection button 13-3 ′ when the pattern of the composite image 13-3 is not seen. In addition, when the pattern is not seen in any of the composite images 13-1 to 13-6, the user selects the selection button 13-7 '.

  The visual acuity determination unit 46 determines whether or not the selection button has been selected by the user based on the operation information from the operation unit 10 (step S102). If there is no user selection (step S102; No), the visual acuity determination unit 46 performs the process of step 102 again.

  When there is a user selection (step S102; Yes), in step S103, the visual acuity determination unit 46 determines the user's visual acuity, for example, by determining which button the user has selected. For example, when the user selects the selection button 13-3 ′, the user sees the pattern of the composite image 13-2 corresponding to the visual acuity 0.4, and the composite image 13-3 corresponding to the visual acuity 0.6. The visual acuity determination unit 46 determines that the user's visual acuity is 0.4 or more and less than 0.6. In step 103, the display control unit 45 displays the visual acuity determination result by the visual acuity determination unit 46 on the display unit 20 (step S103).

  When the user selects the selection button 13-7 ', the visual acuity determination unit 46 determines that the visual acuity of the user is 0.2 or less. After displaying the visual acuity determination result, the display control unit 45 displays a menu screen on the display unit 20 and ends the visual acuity determination process.

  According to the present embodiment, the vehicle display control apparatus 100 divides the original image A and the original image B into a plurality of regions (divided regions), and the reference low frequency and the reference high with different peaks for each divided region. By generating a composite image using the frequency and generating one composite image again, there are three or more viewing environments (an environment with three or more visual acuities at the same visual acuity determination distance, and the size of the composite image to be displayed is three or more. In an environment or an environment in which the distance between the composite image and the user is 3 or more), an image that appears to be three or more types of images can be generated.

  Further, by making an image that appears as three or more types of images in three or more viewing environments as a composite image for visual acuity determination, an image that appears as two or more types of images in two or more viewing environments is used for visual acuity determination. The range of visual acuity to which the user's visual acuity belongs can be further limited by a single visual acuity determination. For example, in the case where a composite image that looks like different images with a visual acuity of 1.0 as a boundary (an image that appears as two or more types of images in two or more viewing environments) is used for visual acuity determination, the visual acuity of the user is determined in one visual acuity determination Can only determine whether the eyesight is 1.0 or more or less than 1.0. On the other hand, when a composite image (images that look like three or more types of images in three or more viewing environments) is used for visual acuity determination, the visual acuity determination is performed once. Thus, it can be determined whether the user's visual acuity is 0.5 or more or less than 0.5, or 0.5 or more or less than 1.5, or 1.5 or more or less than 1.5.

  In addition, this invention is not limited to said embodiment, Various deformation | transformation (a deletion of a component is included) and application are possible for said embodiment.

  In the above embodiment, when generating a composite image from two original images (or divided regions), a band pass filter is applied to both original images, and a high frequency band (also referred to as a high frequency component) is the main. An image of a frequency spectrum as a component (in the above embodiment, a high frequency band. The main component includes a case where only the high frequency band is used as a component) and a low frequency band (also referred to as a low frequency component). Is generated as a main component (in the above embodiment, the low frequency band. The main component includes the case where only the low frequency band is used as a component). Although an image is generated, if a predetermined condition is satisfied, the filter need not be applied to at least one of the original images.

  For example, a frequency spectrum having a high frequency band as a main component, for example, an original image having a frequency spectrum that is low enough to ignore the intensity of other frequency bands (particularly the low frequency band) compared to the high frequency band (for example, contour) It is not necessary to apply a high-band pass filter to the image such as the image 4-2 in FIG. This is because such an image is an image to which a high bandpass filter has already been applied. In such a case, the synthesized image may be generated using the original image as it is (using a frequency spectrum obtained by subjecting the original image to discrete Fourier transform if necessary).

  For example, a frequency spectrum whose main component is a low frequency band, for example, an original image having a frequency spectrum that is so low that the intensity of other frequency bands (especially high frequency band) is negligible compared to the low frequency band (for example, FIG. 11 is not necessary to apply a low-band pass filter. This is because such an image has already been applied with a low-band pass filter. In such a case, the synthesized image may be generated using the original image as it is (using a frequency spectrum obtained by subjecting the original image to discrete Fourier transform if necessary).

  The high frequency band may be a high frequency band as compared with the low frequency band. For example, a high frequency band has a peak frequency (for example, the lowest frequency in the band if the peak is a frequency band composed of a set of a plurality of frequencies), and a low frequency band peak frequency (a plurality of peaks). If it is a frequency band composed of a set of frequencies, it may be a frequency band higher than, for example, the highest frequency in that band. Further, the lowest frequency in the high frequency band may be higher than the highest frequency in the low frequency band.

  The reference high frequency and the reference low frequency may be composed of a plurality of frequencies in a predetermined band. In such a case, the reference high frequency and the reference low frequency are the same as those in the high frequency band and the low frequency band. That is, it is only necessary that the lowest frequency of the reference high frequency is higher than the highest frequency of the reference low frequency.

  In addition, for example, when two reference high frequencies (when composed of a plurality of frequency bands) or two reference low frequencies (when composed of a plurality of frequency bands) are compared, the two are different from each other. Includes a case where only a part of the bands overlaps (including that one band includes all of the other bands, but the other band does not include all of the one band).

  In addition, for example, when two high frequency bands or two low frequency bands are compared with each other, the difference between the two is that the bands do not overlap, or the bands partially overlap (one of the When the band is different, such as when the band includes all of the other band but the other band does not include all of the one band, and when the peak frequency is different (the peak frequency is different from the band of multiple frequencies) The same as when the band is different.).

  The visual acuity determination of the above embodiment is not limited to what is performed in the vehicle, but may be used for what is performed at home or in the medical field. That is, the vehicle display control device 100 may be a visual acuity determination device. In addition, the use of the composite image in the embodiment is not limited to the visual acuity determination and can be used for various uses. In particular, three or more viewing environments (such as those generated in the second embodiment) (when the visual acuity at the same visual acuity determination distance is three or more, when the size of the composite image to be displayed is three or more, or the composite image and the user In the case where there are three or more distances), an image that looks like three or more types of images has an interesting appearance, and can be printed on an advertising medium or the like, for example. Thus, the vehicle display control apparatus 100 may be an image processing apparatus. The composite image may not be displayed on a display unit such as a display, may be printed on a printing medium such as a paper medium, or may be stored in a predetermined storage device. In other words, the composite image only needs to be output after generation. In the above embodiment, the composite image is generated every time it is output. However, the composite image itself may be stored in advance in the storage unit and output as necessary (that is, discrete). Fourier transform or filter may not be used), and at least one of the images extracted from the high frequency band and the low frequency band may be stored in advance in the storage unit 30 (that is, discrete Fourier transform or It is not necessary to use a filter.) The data format of the data representing the image stored in the storage unit 30 may be any format. For example, the image is specified by data representing a frequency spectrum, image data representing a frequency spectrum (data such as the image 8A ′ in FIG. 8), image data obtained by inverse discrete Fourier transform of the frequency spectrum, or the like. It may be an image. For data representing a frequency spectrum, image data representing a frequency spectrum, and the like, an image can be obtained by performing inverse discrete Fourier transform on the frequency spectrum. Further, in the above description, as an example of presenting a composite image at the time of visual acuity determination or the like, the composite image is displayed on the display unit 20, but the composite image printed on paper or the like is mechanically presented. May be. In this way, presenting a composite image includes mechanically presenting a representation (printed material or the like) representing the composite image.

  When the synthesized image obtained by synthesizing the first original image and the second original image is viewed, the first original image is seen as at least a subject in the first original image is reflected in the synthesized image. What is necessary is that it can be recognized that what is expressed in the composite image is not the main image of the second original image but the main image of the first original image. In addition, when a synthesized image obtained by synthesizing the first original image and the second original image is viewed, if it looks like the second original image, at least a subject reflected in the second original image becomes a synthesized image. What is necessary is just to be able to recognize that what is expressed by the composite image is not the main image of the first original image but the main image of the second original image, such as being recognized as being captured.

  When generating different composite images (images that look different depending on visual acuity, etc.) using bandpass filters of different reference high frequencies and reference low frequencies, one of the reference high frequency and the reference low frequency Just move it.

  In the first embodiment, the composite image is presented to the user once, and the user is asked to select whether the composite image looks like the first original image or the second original image, and the user selects which one is selected. In this way, it is determined whether the user's visual acuity is greater than or less than the first visual acuity, but other composite images are presented according to the user's selection (the visual acuity determination process is executed again), and the range to which the user's visual acuity belongs is determined. You may further limit. For example, a plurality of composite images are prepared (for example, the composite images 13-1 to 13-6 before the single composite image 13 in the second embodiment), and the composite image 13-1 (visual acuity) shown in FIG. 0.2), a selection screen for prompting the user to select whether the image 11-1 or the image 12-1 is visible is displayed, and the operation information supplied from the operation unit 10 is the image 12- When 1 is information indicating that 1 is selected, it is determined that the user's visual acuity is 0.2 or more. Subsequently, a selection screen is displayed to the user as to whether the composite image 13-2 (composite image corresponding to visual acuity 0.4) shown in FIG. 11 looks like the image 11-2 or the image 12-2, and the supplied operation Depending on the user's selection indicated by the information (selection of whether the composite image 13-2 looks like the image 11-2 or the image 12-1), the user's visual acuity is 0.2 or more and less than 0.4 or 0.4 It may be determined that this is the case. Furthermore, the process of presenting another composite image may be repeatedly executed according to the user's selection until the range to which the user's visual acuity can no longer be limited. Note that the range in which the user's visual acuity cannot be further limited means that when the visual acuity determination is performed using the composite images 13-1 to 13-6 illustrated in FIG. When it is determined that the user's visual acuity is 1.2 or more. In the conventional visual acuity determination, when the visual acuity is high, it is necessary to gradually reduce the visual acuity determination design (for example, the Landolt ring). In such a case, it is necessary to make the pixels of the display unit fine. However, in such a modified example, basically, it is not necessary to change the size of the image (the size of a plurality of synthesized images to be prepared is It is not necessary to make the pixels of the display portion finer because they may be the same.

  In the second embodiment, each of the two original images is divided, a combined image is generated for each divided region, and a single combined image is generated again, whereby three or more viewing environments (the visual acuity at the same visual acuity determination distance is increased). When there are 3 or more, when the size of the composite image to be displayed is 3 or more, or when the distance between the composite image and the user is 3 or more), an image that looks like three or more types of images is generated. For example, based on two original images, a plurality of composite images (both are composite images from the two original images, but using a reference high frequency and a reference low frequency bandpass filter) And a composite image generated using a filter in which at least one of the reference low frequencies is different, and a plurality of generated composite images may be combined to generate one composite image.

  The band-pass filter used has a so-called Gaussian-shaped frequency characteristic (passing frequency characteristic) that attenuates the passing frequency as the frequency goes away with the peak frequency as the center. Although not attenuated, a filter having a rectangular frequency characteristic (ideal frequency specification) that abruptly attenuates a frequency deviating from the frequency band to be passed may be used. Further, the high band pass filter may be a high pass filter (in this case, the reference high frequency may be the lowest frequency among the frequencies to be passed (for example, the lowest frequency when an ideal high pass filter is considered). ). The low-band pass filter may be a low-pass filter (in this case, the reference high frequency may be the highest frequency among the frequencies to be passed (for example, the highest frequency when an ideal low-pass filter is considered)). Good. The filter applied to the original image may be any one of the above filters that can extract a high frequency band or a low frequency band.

  Further, when the visual acuity is determined using the composite image, the composite image gradually appears from one original image to the other original image according to the visual acuity when the visual acuity determination distance is the same (strict 1 Since it does not determine which original image is visible based on the visual acuity of a point), if one of the original images is seen, it is determined that it is greater than the first visual acuity, and if it appears to be the other original image Is determined to be less than the second visual acuity, and the first visual acuity and the second visual acuity may not be the same. For example, when the selection screen for prompting the user to select whether the composite image 4 shown in FIG. 3 looks like the image 4-1 or the image 4-2 is displayed, the operation information supplied from the operation unit 10 is the image 4- If it is information indicating that 2 is selected, it is determined that the user's visual acuity is 0.4 (first visual acuity) or more, and if it is information indicating that image 4-1 is selected, the user May be determined to be less than 0.2 (second vision). At this time, the second visual acuity is lower than the first visual acuity. Further, when the user's selection is the composite image 4-2, it may be determined that the user's visual acuity is less than 0.2, and the user's visual acuity is such that at least the image 4-1 can be seen. Therefore, for example, the user's visual acuity may be determined to be 0.1 or more and less than 0.2. As described above, the first visual acuity and the second visual acuity may be visual acuity having a certain range (for example, 0.1 or more and less than 0.2) instead of a certain one.

  Further, the composite image has items (whether it looks as the first original image or the second original image) that the user visually recognizes according to the predetermined visual acuity, the distance to the composite image, the display size of the composite image, and the like. Any image may be used as long as the image has a characteristic of changing. For example, as shown in FIG. 14A, a low frequency band of a gray image (background image) 19-1 (Note that such a one-color image is not an extracted low frequency band, but the original image as it is. And a high-frequency band of an image (positive image) 19-2 representing the characters “OK” may be used. Further, as shown in FIG. 14B, the low frequency band of the background (noise image) 20-1 including noise and the high frequency band of the image 20-2 representing the characters “OK”. It may be a composite image. Further, as shown in FIG. 14C, the low frequency band of an image (negative image) 21-1 representing the characters “NG”, the high frequency band of an image 21-2 representing the characters “OK”, It may be a composite image.

  In the second embodiment, a plurality of synthesized images having the same composition source image are generated and arranged on the selection screen 91 for visual acuity determination. However, if the arranged composite images are images corresponding to the visual acuity to be determined, respectively. The original images of these synthesized images may be images that have no relationship with each other. For example, the original image of the composite image 13-1 illustrated in FIG. 13 may be an image representing characters, and the original image of the composite image 13-2 may be an image representing a human face.

  In the embodiment, the program to be executed is a computer-readable recording medium such as a flexible disk, a CD-ROM (Compact Disc Read-Only Memory), a DVD (Digital Versatile Disc), and an MO (Magneto-Optical disc). It is also possible to configure a system that executes the above-described processing by storing and distributing the program and installing the program.

  Further, the program may be stored in a disk device or the like of a predetermined server device on a communication network such as the Internet, and may be downloaded, for example, superimposed on a carrier wave.

  In addition, when the above functions are realized by sharing the OS, or when the functions are realized by cooperation between the OS and the application, only the part other than the OS may be stored in the medium and distributed. You may download it.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Steering 2a Main-body part 2b Steering wheel 3 User 4, 8, 13, 13-1 to 13-6, 19-21 Composite image 4-1, 4-2, 3-2, 8A, 8B, 11, 12 19-1, 19-2, 20-1, 20-2, 21-1, 21-2 Images 4-1 ′, 4-2 ′, 13-1 ′ to 13-7 ′, 16-1 ′ to 16-8 'selection button 8A', 8B ', 8C Frequency spectrum image 10 Operation part 11-1 to 11-6, 12-1 to 12-6 Division area 20 Display part 30 Storage part 31 Reference frequency table 40 Control part 41 Distance acquisition unit 42 Low frequency component extraction unit 43 High frequency component extraction unit 44 Compositing unit 45 Display control unit 46 Visual acuity determination unit 91 Selection screen for visual acuity determination 100 Display control device for vehicle A Seatback angle L Visual acuity determination distance P Eye point S Slide amount

Claims (8)

A device for determining visual acuity for determining the visual acuity of a subject,
Presenting means for presenting to the subject a composite image of a first image having a frequency spectrum whose main frequency band is a low frequency band and a second image having a frequency spectrum whose main band is a high frequency band. And
The composite image is recognized as either the first image or the second image according to the visual acuity of the subject who is a predetermined distance away from the composite image presented by the presenting means. Is a possible image,
An apparatus for determining visual acuity characterized by the above. The image processing apparatus further includes a combining unit that combines the first image and the second image.
The visual acuity determination device according to claim 1. The synthesizing unit includes a first image generation unit that acquires a first original image, extracts the low frequency band from the first original image, and generates the first image.
The apparatus for determining visual acuity according to claim 2. The synthesizing unit includes a second image generation unit that acquires a second original image, extracts the high frequency band from the second original image, and generates the second image.
The visual acuity determination device according to claim 2, wherein the visual acuity determination device is a visual acuity determination device. The presenting means further includes distance acquisition means for acquiring a distance between the subject and the composite image to be presented,
As the composite image, there are a first composite image and a second composite image,
The presenting means can present either the first composite image or the second composite image according to the distance acquired by the distance acquisition means,
In the first synthesized image and the second synthesized image, at least one of the low frequency band and the high frequency band is different in band or peak frequency is different,
The visual acuity determination device according to claim 1, wherein the visual acuity determination device is a visual acuity determination device. As the composite image, there are a first composite image and a second composite image,
The presenting means can present the first composite image and the second composite image simultaneously,
In the first synthesized image and the second synthesized image, at least one of the low frequency band and the high frequency band is different in band or peak frequency is different,
The visual acuity determination device according to claim 1, wherein the visual acuity determination device is a visual acuity determination device.   A vehicular display control apparatus comprising the visual acuity determination apparatus according to claim 1. In the computer for judging the eyesight of the subject,
Generating a composite image of a first image having a frequency spectrum whose main band is a low frequency band and a second image having a frequency spectrum whose main band is a high frequency band;
A presentation step of displaying the composite image generated by the generation step on a predetermined display unit and presenting the composite image to the target person;
The composite image is recognized as either the first image or the second image according to the visual acuity of the subject who is a predetermined distance away from the composite image presented in the presenting step. Is a possible image,
A program characterized by that.