JP2003044849A - Device and program for evaluating readability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To objectively evaluate character readability when slide images are prepared while considering various situation differences between when the slide images are prepared and when presentation is performed. SOLUTION: A microcomputer converts a sample image so as to correspond to a projector characteristic (step ST11). Character colors (L0 , a0 and b0 ) and background colors (L1 , a1 and b1 ) by a CIELAB color system are extracted from the sample image to calculate color differences D (step ST12). Resolution (deg) is determined on the basis of the operated color differences D and resolution characteristic data (step ST13). Then, a score table is referred to, and a score is decided on the basis of the character size of the sample image and the resolution determined in the step ST13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a readability evaluation apparatus and program, and more particularly to a readability evaluation apparatus and program suitable for use in creating a slide screen for presentation.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
When creating a slide screen for a presentation,
The operator creates a slide screen while looking at the computer screen by using the computer in which the presentation software is installed. In such a case, presentation software such as Microsoft's "PowerPoint" can display a warning message on the computer screen and give advice to the character when the point of the character is smaller than the set value. . Then, the operator needs to create a slide screen so that the characters can be easily read in consideration of his / her experience while receiving the advice on the characters.

By the way, the surrounding environment and equipment are completely different between when the slide screen is created and when the presentation is made. For example, there are the following differences.

Creation of slides is typically done in a bright room with lighting. In contrast, the presentation is given in a dark room with the lights off. Also,
CRT (Cathode Ray Tube) or L
A high-brightness display device such as a CD (Liquid Crystal Display) is used. On the other hand, at the time of presentation, a liquid crystal projector, that is, a low-luminance display device is used.

At the time of slide making, from 14 inches to 21
A slide screen is displayed on a display device of about inch. On the other hand, at the time of presentation, the slide screen is displayed on a large screen of 60 inches or more.

At the time of creating a slide, the distance from the operator to the slide screen is 50 cm to 70 cm.
Relatively short. On the other hand, at the time of presentation, the distance from the observer to the slide screen is 3 m or more, which is considerably long.

At the time of creating a slide, the operator who evaluates the readability of characters is the same as the creator of the slide screen and is of the same age. On the other hand, at the time of presentation, the observer who evaluates the readability of characters is different from the creator of the slide screen. The age of the observer is generally higher than that of the creator of the slide screen.

As described above, the surrounding environment and equipment are completely different when the slide screen is created and when the presentation is performed. Therefore, even if the operator determines that the character is easy to read when creating the slide screen, the observer may determine that the character is not easy to read during the presentation. In other words, when creating a slide screen, it was very difficult to evaluate the readability of characters at the time of presentation.

Further, the operator has to subjectively judge whether or not the characters on the slide screen are easy to read, taking his experience and the like into consideration. For this reason, the readability evaluation differs depending on the operator, and there has been a demand for making the readability evaluation objective.

The present invention has been proposed to solve the above-mentioned problems, and objectively evaluates the readability of characters while taking into consideration the differences in various situations during slide screen creation and during presentation. It is an object of the present invention to provide a readability evaluation device and a program that can be performed.

[0011]

The invention according to claim 1 is
Using the signal conversion means for converting the color signal of the display image into a color signal according to the characteristics of the projector and the color signal converted by the signal conversion means, the respective colors and brightness of the characters and background of the display image By using a color difference calculation means for calculating a color difference including, and a resolution characteristic indicating a resolution corresponding to the color difference,
Resolution determining means for determining the resolution corresponding to the color difference calculated by the color difference calculating means, the resolution determined by the resolution determining means, the screen size of the image display device, and the distance to the screen. And an evaluation unit that evaluates the readability of the character based on the above.

According to a fourth aspect of the present invention, there is provided a computer,
The color signal of the display image is converted into a color signal according to the characteristics of the projector, and the converted color signal is used to calculate a color difference including each color and brightness of the characters and background of the display image, The resolution corresponding to the color difference is used to determine the resolution corresponding to the calculated color difference.
It is characterized in that the readability of the character is evaluated based on the determined resolution, the size of the screen of the image display device, and the distance to the screen.

According to the present invention, the color signals of the display image are converted into color signals according to the characteristics of the projector. Normally, even for display images composed of the same color signal, for example, the display images of the CRT and the projector have different colors. Therefore, in order to make the colors of the display image the same, the color signal of the display image is converted according to the characteristics of the projector.

Then, with respect to the display image having the character and the background after the color signal conversion, the color difference including the color and the brightness of the character and the background is calculated. The color difference is a contrast that includes both the color and brightness of the character and the background. Then, the resolution corresponding to the color difference, that is, the visual spatial frequency characteristic is used to determine the resolution corresponding to the calculated color difference.

On the other hand, the readability of characters is determined by the resolution and the character size. The character size referred to here is an angle (visual angle) at which the character looks into the eyes of the observer. Therefore, the readability of the character is evaluated based on the determined relationship between the resolution and the size of the character. At this time, it is advisable to prepare a table in which the readability of the characters is predetermined based on the relationship between the resolution and the character size. This makes it possible to objectively evaluate the readability of characters while considering the characteristics of the projector.

The relationship between the character size and the viewing angle when creating a slide is the size of the screen and the viewing distance when projected by a projector (the distance between the observer and the screen).
Can be obtained from As a result, the readability of characters can always be objectively evaluated even when the size of the screen or the distance to the screen changes.

According to a second aspect of the present invention, in the first aspect of the invention, the evaluating means calculates the size of the character based on the size of the screen, and the calculated character size and the resolution determining means. The readability of the character is evaluated based on the resolution determined in step 1.

According to a fifth aspect of the invention, in the invention according to the fourth aspect, the computer is caused to calculate the size of the character based on the size of the screen, and the calculated size of the character and the determined resolution. The readability of the character is evaluated based on the.

According to the second and fifth aspects of the invention, the fact that the character size is inversely proportional to the screen size is used to calculate the character size based on the screen size. Furthermore, as mentioned above, the readability of a character is determined by the resolution and the size of the character.
The readability of the character can be evaluated based on the calculated size of the character and the determined resolution. That is, even if the size of the screen changes, the readability of the characters can always be objectively evaluated according to the change.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described above, the evaluation means calculates the size of the character based on the distance to the screen, and reads the character based on the calculated size of the character and the resolution determined by the resolution determination means. Characterized by evaluating the ease.

The invention according to claim 6 is the invention according to claim 4 or 5.
In the invention described above, the computer is caused to calculate the size of the character based on a distance to the screen, and the readability of the character is evaluated based on the calculated size of the character and the determined resolution. It is characterized by

According to the third or sixth aspect of the present invention, the size of the character is proportional to the distance to the screen, and the size of the character is calculated based on the distance to the screen. Further, as described above, the readability of the character can be evaluated based on the calculated size of the character and the determined resolution. That is, even if the distance from the observer to the screen changes, the readability of the characters can always be objectively evaluated in response to the change.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the display screen designing device 1 having the configuration shown in FIG. 1 will be described as an example. The display screen design apparatus 1 is suitable for use in designing a slide screen when giving a presentation using a projector.

As shown in FIG. 1, the display screen designing apparatus 1 specifically includes an interface 11 for inputting / outputting sample images, a mouse 12 as a pointing device, and parameters for setting a slide screen. A keyboard 13 for inputting, for example, a hard disk drive 15 for storing operation programs and application programs, an LCD (Liquid Crystal Display) 16 for displaying a slide screen, an operation screen, etc., and a microcomputer 20 for overall control. And are equipped with.

When a sample image for a slide screen is input, the interface 11 inputs the sample image via the data bus 17 to the microcomputer 20.
Supply to. The sample image is composed of at least a character image and a background image.

The mouse 12 is used when a predetermined button on the operation screen displayed on the LCD 16 is clicked, the condition of the visual environment is set, and the background color and the character color are selected. The keyboard 13 is used when inputting the character size, the age of the observer, the size of the screen, and the like.

The hard disk drive 15 stores an operation program and an application program for controlling the design of the slide screen. The LCD 16 displays a sample image input via the interface 11, an operation screen for setting parameters for image conversion of the sample image, a sample image after image conversion, and the like.

On the other hand, the microcomputer 20 has a CPU 21 which executes arithmetic processing for designing a slide screen.
And a RAM 22 that is a data work area and a CPU
The ROM 23 stores the control program 21 and a predetermined table.

Here, in the hard disk drive 15, as a part of the above-mentioned application program, for example, a program for executing a main routine or a subroutine, and a projector characteristic table for converting a sample image according to the characteristics of the projector. ,
Resolution characteristic data, score table showing legibility of characters,
The recommended color data for presenting the recommended color according to the rating is stored.

The projector characteristic table is a table for converting the sample image so as to correspond to the characteristic of the projector. The reason for providing the projector characteristic table is as follows. LCD 1 of display screen setting device 1
6 and the same RG for the projector for presentation
Even if the B signal is input, each RGB primary color, white point,
If the gamma characteristic or the like is different, the color of the displayed image will be different. Therefore, in order to make the color displayed on the LCD 16 the same as the color displayed by the projector, a projector characteristic table for converting RGB signals according to the characteristics of the projector is provided. The projector characteristic table is preferably set for each projector model.

The projector characteristic table is shown in FIG.
, The sample images are arranged from (R, G, B) to (L, x,
y). Note that FIG. 2 shows only representative RGB values and Lxy values.

The projector characteristic table may be selected from a menu (not shown),
It may be set by default as a representative value of a typical projector.

The resolution characteristic data is data showing a visual spatial frequency characteristic, specifically, a characteristic of resolution with respect to color difference. FIG. 3 shows the resolution characteristic data. Here, the resolution characteristic data generally differs depending on the age. Therefore, resolution characteristic data is provided for each of 23 years old, 30 years old, 40 years old, 50 years old, 60 years old, and 70 years old.

Further, the resolution characteristic data is provided as another condition for each illuminance of the screen surface when the projector is off, and for each brightness of the room in which the projector is installed.

As shown in FIG. 4, the score table is a table showing scores determined by resolution and character size. According to the score table, for example, the resolution is X [de
g] and the character size is Y [deg], Y ≧ f1
In the case of (X), a score of 1, which means "easy to read",
When f2 (X) ≦ Y <f1 (X), the score is “easy to read” 4, and when f3 (X) ≦ Y <f2 (X), “normally read” is the score 3, f4 (X) ≦ Y <
A score of 2 which indicates "difficult to read" at f3 (X),
When Y <f4 (X), a score of 1 indicating "unreadable"
It has become.

The recommended color data is used when presenting the recommended colors of the background and characters. The recommended color data has color data having different lightness and saturation for each hue.

In the display screen designing apparatus 1 configured as described above, the microcomputer 20 converts the sample images to design a slide screen that is easy to see.
The processing from step ST1 onward shown in FIG. 5 is executed.

In step ST1, the microcomputer 20 determines whether a sample image is externally captured via the interface 11, waits until the sample image is captured, and when the sample image is captured, the microcomputer 20 proceeds to step ST2.

In step ST2, the microcomputer 20 determines whether the necessary parameters have been input by operating the mouse 12 or the keyboard 13. Required parameters include, for example, the distance from the observer to the screen (visual distance), the screen size, the illuminance of the screen when the projector is off, the age of the observer, the brightness of the room in which the projector is installed, etc. is there. Then, the microcomputer 20 waits until the necessary parameters are input, and when the necessary parameters are input, the microcomputer 20 proceeds to step ST3.

In step ST3, the microcomputer 20 calculates a score indicating the readability of the character based on the image data of the sample image. Here, the microcomputer 20 is specifically, step S shown in FIG.
The subroutine from T11 to step ST15 is executed.

At step ST11, the microcomputer 20 converts the sample image so as to correspond to the characteristics of the projector. Specifically, using the projector characteristic table shown in FIG. 2, a sample image (R,
G, B) to (L, x, y) and step ST
Move to 12.

In step ST12, the microcomputer 20 uses the CIELAB color system to characterize the characters (L ₀ , a ₀ , b ₀ ) and the background colors (L ₁ , a ₁ ,
b ₁ ) is extracted, the color difference D is obtained by calculating the equation (1), and the process proceeds to step ST13.

[0043]

[Equation 1]

The color difference D is a contrast between a character and a background including both color and brightness. Note that ΔL, Δa, Δ
b represents the colors of the characters and the background in the CIELAB color system by (L ₀ , a ₀ , b ₀ ) and (L ₁ , a ₁ , b ₁ ) respectively, and the following formula (2) to formula (4) ).

[0045]

[Equation 2]

In step ST13, the microcomputer 20 calculates the color difference D calculated in step ST12,
The resolution [deg] is determined based on the resolution characteristic data stored in the hard disk drive 15. That is, the microcomputer 20 selects the resolution characteristic data corresponding to each parameter input in step ST2 from the plurality of resolution characteristic data stored in the hard disk drive 15, and refers to the selected resolution characteristic data. , The resolution is determined based on the color difference, and the process proceeds to step ST14.

In step ST14, the microcomputer 20 refers to the rating table stored in the hard disk drive 15, and refers to the character size on the slide creation screen, the resolution determined in step ST13, and the screen size input in advance. And the distance to the screen and the score is determined.

First, the microcomputer 20 calculates the character size. In the score table shown in FIG. 4, the character size is represented by the angle (visual angle) at which the character looks into the observer's eyes. The relationship between the viewing angle and the character size on the creation screen is as shown in Expression (5).

[0049]

[Equation 3]

H: Character size on created screen [mm] Y: Viewing angle of character [deg] S: Screen size [mm] S ₀ : Screen size [mm] when creating a slide document L: Distance to screen ( Viewing distance) [mm] Next, the microcomputer 20 determines in which area the coordinate position specified by the resolution and the character size calculated by equation (5) is, and based on the area to which the coordinate position belongs. To determine the score.

For example, when the resolution is 0.02 [deg] and the character size is 0.5 [deg], the coordinates of the resolution and the character size are f4 (X) ≤Y <f3 as shown in FIG.
Since it is in the area (X), the microcomputer 20
Determines a score of 2.

When the determination of the score is completed, the microcomputer 20 exits this subroutine and moves to step ST4 shown in FIG.

As described above, the microcomputer 20
Can determine the resolution corresponding to the color difference of the sample image by referring to the visual spatial frequency characteristics based on the surrounding environment and age, and evaluate the readability of the character from the relationship between the resolution and the character size. it can. That is, it is possible to accurately evaluate the readability of a character by considering not only the character color, the background color, and the character size, but also individual differences such as the surrounding environment and age.

At step ST4, the microcomputer 20 displays an operation screen (not shown) on the LCD 16, and then proceeds to step ST5. Here, the operation screen displays the score obtained in step ST3 and the values of the background color and the character color at that time (for example, respective values of red (R), green (G), and blue (B)). .

On the operation screen, the background recommended color button for presenting the recommended background color, the character recommended color button for presenting the recommended color of the character, the background color of the sample image, the character color, etc. are set. And a setting button for setting.

In step ST5, the microcomputer 20 determines whether or not the setting button on the operation screen displayed on the LCD 16 is clicked. When the button is clicked, the process proceeds to step ST8, and when it is not clicked, the process proceeds to step ST6. Transition.

In step ST6, the microcomputer 20 determines whether any one of the recommended background color button and the recommended character color button has been clicked. If any one of them has been clicked, the process proceeds to step ST7, and both of them are clicked. If not clicked, the process returns to step ST5.
In the following description, it is assumed that the background recommendation button is clicked.

At step ST7, the microcomputer 20 displays a plurality of recommended colors from evaluation 3 to evaluation 5, and determines one recommended color from these recommended colors according to the instruction of the operator. Here, specifically, the sub-routines after step ST21 shown in FIG. 7 are executed.

In step ST21, the microcomputer 20 sets "n = 3" as the initial value of the rating n, and proceeds to step ST22.

In step ST22, the microcomputer 20 refers to the rating table shown in FIG. 4, finds the range of resolution corresponding to the character size of the sample image in the area of the rating n, and proceeds to step ST23.

In step ST23, the microcomputer 20 selects the resolution characteristic data corresponding to each parameter input in step ST2 from the plurality of resolution characteristic data. Then, the range of chromaticity D corresponding to the range of resolution obtained in step ST22 is obtained by referring to the resolution characteristic data, and the process proceeds to step ST24.

In step ST24, the microcomputer 20 refers to the equations (1) to (4) described above, and the background color (L ₁ , a) that satisfies the range of the chromaticity D obtained in step ST23. ₁ , b ₁ ) and step S
Move to T25. The color (L ₁ , a ₁ , b ₁ ) thus obtained is one of the recommended background colors.

In step ST25, it is determined whether the score n is "5". If the score n is "5", the process proceeds to step ST27. If the score n is not "5", the process proceeds to step ST26. . In step ST26, the score n
Is incremented by 1 and the process returns to step ST22.

The microcomputer 20 performs the processing from step ST21 to step ST26 as described above.
By repeating this, the recommended colors for each of the grades 3 to 5 are obtained.

At step ST27, the microcomputer 20 reads out the recommended color data indicating the background colors (L ₁ , a ₁ , b ₁ ) obtained at step ST24 from the hard disk drive 15, and as shown in FIG. L
Display the color palette on CD16. A plurality of colors arranged in a matrix are displayed on the color palette. The colors are arranged so that the lightness changes in the vertical direction and the saturation changes in the horizontal direction.

At this time, the operator can select a desired background color from the color palette. When the operator operates the mouse 12 and clicks a desired color (for example, a recommended color with a score of 5), the microcomputer 20 determines the clicked color as the background color,
After the processing of the subroutine is completed, step S shown in FIG.
Return to T4.

Then, the microcomputer 20 is L
A new setting screen is displayed on the CD 16. The new operation screen displays the score obtained in step ST3, the value of the first input character color, and the value of the background color set in step ST27.

On the other hand, step ST8 when it is determined that the setting button is clicked in step ST5 shown in FIG.
Then, the microcomputer 20 performs image processing on the sample image so that the background color and the character color at the time when the setting button is clicked are obtained. It should be noted that the microcomputer 20 may not perform the image processing when the background color and the character color have not changed since the input of the sample image.

Then, the microcomputer 20 displays the sample image which has been subjected to the image conversion processing on the LCD 16. At this time, the operator confirms whether the characters in the sample image are easy to see, and then the mouse 12 or the keyboard 1
3 can be operated to instruct to print out the sample image. When instructed to print out the sample image, the microcomputer 20 transmits the sample image to a printer (not shown) via the interface 11. As a result, the slide screen is output from the printer.

As described above, the display screen designing apparatus 1 determines the resolution based on the spatial frequency characteristics based on the surrounding environment and age, and gives the score indicating the readability of the character from the relationship between the resolution and the character size. By determining, the readability of the character can be objectively presented to the operator.

In addition, the display screen setting device 1 is designed so that various conditions (for example, projector characteristics,
The resolution characteristic data that considers the screen size, screen illuminance when the projector is off, and the observer's conditions (for example, age and viewing distance) is stored, and the resolution characteristic data is selected according to the input parameters and the characters are selected. Since the score indicating the readability of is calculated, it is possible to objectively present the readability of the character at the time of presentation when creating the slide screen.

Further, the display screen designing apparatus 1 can present the recommended color of the character or background to the operator by calculating the rating for the color arrangement on the color palette and displaying the rating for each color.

The present invention is not limited to the above-described embodiments, and various design changes can be made within the scope of the invention described in the claims.
For example, in the present embodiment, the case where the background recommended button is clicked in the processing from step ST21 to step ST27 has been described as an example, but the same processing is executed even when the character recommended button is clicked. Of course, it can be done.

Further, the resolution characteristic data stored in the display screen setting device 1 is not limited to the above-mentioned embodiment, and may be provided for each other presentation condition or observer condition. Thereby, the display screen setting device 1
Under a more detailed condition, the readability of characters can be objectively presented to the operator.

[0075]

According to the readability evaluation apparatus and the program of the present invention, the color signal of the display screen is converted into the color signal according to the characteristics of the projector, and the converted color signal is used to display the display screen. The color difference including each color and brightness of the character and the background is calculated, the resolution corresponding to the calculated color difference is determined, the determined resolution, the screen size of the image display device, and the screen By evaluating the readability of the character based on the distance, it is possible to objectively evaluate the readability of the character while considering the characteristics of the projector.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a display screen setting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a projector characteristic table.

FIG. 3 is a diagram showing an example of resolution characteristic data.

FIG. 4 is a diagram showing an example of a score table.

FIG. 5 is a flowchart showing a processing procedure of a main routine of the microcomputer.

FIG. 6 is a flowchart showing a processing procedure of a subroutine of a microcomputer.

FIG. 7 is a flowchart showing a processing procedure of a subroutine of a microcomputer.

FIG. 8 is a diagram showing an example of a color palette.

[Explanation of symbols]

11 Interface 12 mice 13 keyboard 15 hard disk drive 16 LCD 20 microcomputer 21 CPU 22 RAM 23 ROM

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazunori Higuchi             Aichi Prefecture Nagachite Town Aichi District             Ground 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Kazuhiko Sugiyama             Aichi Prefecture Nagachite Town Aichi District             Ground 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Koji Kishi             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. (72) Inventor Kanamori et al.             1 Toyota Town, Toyota City, Aichi Prefecture Toyota Auto             Car Co., Ltd. F-term (reference) 5C061 BB01 BB03 BB07 CC05                 5C079 HB01 HB08 HB11 LA37 LB01                       NA06 PA05                 5L096 AA02 AA06 CA21 DA01 DA03                       FA59 GA40 GA41 MA03

Claims (6)

[Claims] 1. A character and a background of the display image using a signal conversion unit for converting a color signal of the display image into a color signal according to the characteristics of the image display device, and the color signal converted by the signal conversion unit. Resolution determination means for determining the resolution corresponding to the color difference calculated by the color difference calculation means using the color difference calculation means for calculating the color difference including each color and the brightness and the resolution characteristic showing the resolution corresponding to the color difference. Means for evaluating the readability of the character based on the resolution determined by the resolution determining means, the size of the screen of the image display device, and the distance to the screen. Readability evaluation device. 2. The evaluation means calculates the size of the character based on the size of the screen, and the readability of the character based on the calculated size of the character and the resolution determined by the resolution determining means. The readability evaluation apparatus according to claim 1, wherein the readability evaluation apparatus evaluates the readability. 3. The evaluation means calculates the size of the character based on the distance to the screen, and reads the character based on the calculated size of the character and the resolution determined by the resolution determining means. The readability evaluation device according to claim 1, wherein the readability evaluation device evaluates readiness. 4. A computer is caused to convert a color signal of a display image into a color signal according to a characteristic of an image display device, and by using the converted color signal, a color of a character of the display image and a color of a background are displayed. The color difference including the brightness is calculated, and the resolution corresponding to the calculated color difference is determined by using the resolution characteristic indicating the resolution corresponding to the color difference, and the determined resolution and the screen size of the image display device are A readability evaluation program for evaluating readability of the character based on the distance to the screen. 5. The computer is caused to calculate the size of the character based on the size of the screen, and the readability of the character is evaluated based on the calculated size of the character and the determined resolution. The readability evaluation program according to claim 4. 6. The computer is caused to calculate the size of the character based on the distance to the screen, and the readability of the character is evaluated based on the calculated size of the character and the determined resolution. The readability evaluation program according to claim 4 or 5, wherein