JP2003044033A - Device and program for operating luminance, device and method for evaluating easiness of reading, display screen designing device, and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To design an image easy to watch corresponding to environment, age or individual difference through a simple operation. SOLUTION: First of all, basic luminance B0 (=2.869PF<0.44> (Q<-0.21> -1.28))[cd/m<2> ] is obtained (step ST11). Further, an age correction coefficient KA(=30/a) is obtained (step ST12). In such a case, (a) is the age. Further, by using a correlative color temperature t[K] of a background color and a correlative color temperature tW[K] of white, an equality (1) of KC=(1.45exp(-0.00034t)+0.5)/(1.45 exp(-0.00034tw )+0.5) is operated and a color correction coefficient KC is obtained (step ST13). Finally, the age correction coefficient KA and the color correction coefficient KC are multiplied to the basic luminance B0 and an upper limit value B[cd/m<2> ] of display luminance is obtained (step ST14).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brightness calculation device and program, a readability evaluation device and program, and a display screen design device, and particularly to a brightness calculation device suitable for designing a display screen that is easy to see. The present invention relates to a program, a readability evaluation device and program, a display screen design device, and an image display device.

[0002]

2. Description of the Related Art In Japanese Patent Application Laid-Open No. 9-37196, the brightness of a liquid crystal display screen is automatically adjusted according to the brightness of an external environment without lowering the contrast of the display screen. A liquid crystal display device (hereinafter referred to as "prior art 1") has been proposed. Prior art 1
Is to detect the ambient brightness by the solar cell and automatically adjust the brightness of the backlight based on the power generation output of the solar cell.

However, the prior art 1 merely adjusts the display brightness according to the brightness of the external environment and does not consider the visual characteristics, age, background color, etc. of a person. Has a problem that it is not easy to use because it is easy to see or hard to see.

Further, in Japanese Patent Laid-Open No. 9-97333,
An image processing apparatus (hereinafter referred to as "prior art 2") that creates a screen that is easy to see by compensating the display screen so as to compensate for the deterioration of visual function due to age and the difference in visual function due to individual differences.
Is proposed. In the prior art 2, as shown in FIG. 1 of the publication, by operating the age dial 14, the color correction amount, the defocus correction amount, and the spatial frequency characteristic correction amount are independently set according to the age of the viewer. It is something to set. As described above, in Conventional Technique 2, the visual characteristics are changed according to the age.

However, in reality, the visual characteristics vary greatly among individuals even at the same age, and this is more remarkable as the elderly become older. Therefore, the related art 2 has a problem that even if the age is input, it is not always possible to perform the display corresponding to the visual characteristics of the viewer of the screen. There is also a problem that there is a feeling of resistance to directly inputting the age.

Further, in Japanese Patent Laid-Open No. 2000-98994, the degree of readability of a character is stored in advance in association with the character size and the chromaticity difference, and the character is easier to read from the input character size and chromaticity difference. A display screen design device (hereinafter, referred to as "conventional technique 3") for determining the degree of the height has been proposed.
In the related art 3, the readability is judged in four stages of "easy to read", "slightly easy to read", "somehow readable", and "not readable". Then, the character size and the color scheme are changed based on the readability, the readability is determined again, and the character size and the color scheme are changed again to generate an easy-to-read image.

[0007] However, the prior art 3 could not show the designer what character size and color scheme should be set to make it easier to read. For this reason,
The designer has to repeat the process of changing the character size and color scheme and determining the readability again and again,
The operation burden was very heavy.

The present invention has been proposed to solve the above-mentioned problems, and a brightness calculation device and program for designing an easy-to-see image corresponding to the environment, age, and individual differences by a simple operation, and an easy-to-read program. Evaluation device and program,
An object is to provide a display screen design device.

Another object of the present invention is to provide an image display device capable of displaying an easy-to-see image corresponding to the environment, age and individual differences.

[0010]

In order to solve the above-mentioned problems, the present invention provides a document "Brightness in Visual Field at Borderline" which measures the pleasantness and unpleasantness of glare in lighting.
Between Comfort and Discomfort ”M. Luckiesh et al., Illum
The formula shown in inating Eng., 650-670, 1949 (formula of glare characteristics) is modified so that it can be applied to an in-vehicle display.

Here, the above-mentioned document shows the equation (1).

[0012]

[Equation 1]

B: Limit brightness [mL] (1 [mL] = 1
0 / π [cd / m ² ]) P: Position Index (function of position from the center of the visual field) F: Ambient brightness [mL] Q: Glare source size [str] (for example, screen size of in-vehicle display (LCD)) ) I: Constant (108 for illumination) Equation (1) is an empirical equation for obtaining illumination conditions (position, size, brightness) that does not cause discomfort for illumination, and It is obtained from the result of the limit value of pleasantness and discomfort under various lighting conditions.

If the equation (1) is applied to the on-vehicle display as it is, the upper limit luminance which does not cause discomfort becomes too large, which is not realistic. Therefore, the coefficient I that can be applied to the in-vehicle display was experimentally obtained.

The content of the experiment was to use a mock-up for driving a car at night, changing the ambient brightness and the brightness / position / size of the on-vehicle display, and the test subject under each condition. Discomfort was evaluated.
As a result, it was concluded that the coefficient I in the equation (1) is preferably a value in the range of 1 to 2.

Since the unit of the brightness of the formula (1) is represented by [mL], the formula (1) is represented by the following formula (2) when the unit of the brightness is [cd / m ² ]. .

[0017]

[Equation 2]

Therefore, when I = 1, it is expressed by the equation (3).

[0019]

[Equation 3]

When I = 1.5, it is expressed by the equation (4).

[0021]

[Equation 4]

Further, when I = 2, it is expressed by equation (5).

[0023]

[Equation 5]

According to the present invention, the brightness is calculated by using the visual characteristic of glare as described above. That is, the invention according to claim 1 is a basic luminance calculation means for calculating the basic luminance of the display screen based on the visual characteristics of glare, an age correction coefficient calculation means for calculating an age correction coefficient according to age, and a background. A color correction coefficient calculating means for calculating a color correction coefficient based on a correlated color temperature of color and white; a basic luminance calculated by a basic luminance calculating means; an age correction coefficient calculated by the age correction coefficient calculating means; And a brightness calculation means for calculating an upper limit value of the brightness of the display screen based on the color correction coefficient calculated by the color correction coefficient calculation means.

The invention according to claim 3 is a computer,
The basic brightness of the display screen based on the visual characteristics of glare, an age correction coefficient according to age, a color correction coefficient based on the correlated color temperature of the background color and white, respectively, the basic brightness, the age An upper limit of the brightness of the display screen is calculated based on a correction coefficient and the color correction coefficient.

In the first and third aspects of the present invention, the basic luminance is calculated based on the visual characteristic of glare. As the visual characteristic of glare, for example, a glare characteristic is preferable. The basic brightness indicates the upper limit of the brightness of glare at a predetermined age. Moreover, since the upper limit of the brightness of the glare changes depending on the age, an age correction coefficient corresponding to the age is calculated in order to correct the basic brightness. The visual characteristics of glare are
It also depends on the background color. Therefore, the color correction coefficient is calculated so as to correspond to the change in the background color. Then, based on the basic brightness, the age correction coefficient, and the color correction coefficient, the upper limit value of the brightness corresponding to the change of the age or the background color can be calculated. That is, it is possible to obtain the upper limit value of the brightness that does not cause any discomfort, considering the individual difference due to age and the difference in background color.

According to a second aspect of the present invention, in the first aspect of the invention, the basic luminance calculating means is the installation position of the display screen, the luminance around the display screen, and the three-dimensional shape of the display screen viewed from a predetermined position. The basic brightness of the display screen is calculated using at least one of the corners.

According to a fourth aspect of the present invention, in the invention according to the third aspect, at least the installation position of the display screen, the brightness around the display screen, and the solid angle of the display screen viewed from a predetermined position are displayed on the computer. One of them is used to calculate the basic luminance of the display screen.

According to the second and fourth aspects of the invention, the basic brightness has a property that depends on the installation position of the display screen, the brightness outside the vehicle, and the solid angle of the display screen viewed from a predetermined position. Therefore, these parameters can be used to calculate the optimum basic luminance according to the environment around the display screen.

According to a fifth aspect of the present invention, the color difference is calculated by using a color difference calculating means for calculating a color difference including each color and brightness of a character of the display image and the background, and a characteristic of resolution corresponding to the color difference. Based on the relationship between the resolution determined by the resolution determining means for determining the resolution corresponding to the color difference calculated by the calculating means and the resolution determined by the resolution determining means, and the character size,
An evaluation unit that evaluates the readability of the character, and a recommended color display unit that displays a recommended color of the character or the background of the display screen based on the readability of the character evaluated by the evaluation unit are provided. ing.

The invention according to claim 7 is a computer,
The color difference including each color and brightness of the character and the background of the display image is calculated, the resolution corresponding to the calculated color difference is determined, and based on the relationship between the determined resolution and the size of the character, Characteristic readability is evaluated, and a recommended color of the character or background of the display screen is displayed based on the evaluated readability of the character.

According to the fifth and seventh aspects of the invention, the color difference including the color and brightness of each of the character and the background is calculated for the display image composed of the character and the background.
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 a character is determined by the resolution and the character size. 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. Then, based on the readability of the evaluated character, the recommended color of the character or background of the display screen is displayed. This recommended color is a color of a character or a background that can obtain an evaluation equal to or higher than the evaluation of the readability of the character. As a result, it is possible to objectively present a recommended color that makes characters easy to read without depending on the subjectivity of the operator.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the recommended color selecting means for selecting the recommended color of the character or the background displayed by the recommended color displaying means and the recommended color selecting means for selecting are selected. Display screen conversion means for converting the display screen so that the displayed character or the recommended color of the background is obtained.

According to an eighth aspect of the present invention, in the invention according to the seventh aspect, the computer is configured so that the recommended color of the selected character or background is selected from the recommended colors of the displayed characters or background. The feature is that the display screen is converted.

According to the sixth and eighth aspects of the invention, the recommended color selecting means selects a predetermined recommended color from the recommended colors of the displayed characters or background in accordance with the operation of the operator. Then, the display screen is converted so as to have the recommended color of the selected character or background. As a result, the color of the character or the background is converted to the predetermined recommended color, so that the operator can obtain a display screen in which the character is easy to read without performing a complicated operation.

According to a ninth aspect of the present invention, the color difference calculating means for calculating a color difference including each color and brightness of a character and a background of a display screen and a resolution characteristic indicating a resolution corresponding to the color difference are used. A resolution determining unit that determines a resolution corresponding to the color difference calculated by the color difference calculating unit, and an evaluation that evaluates the readability of the character based on the relationship between the resolution determined by the resolution determining unit and the size of the character. And a recommended character size display means for displaying a recommended character size on the display screen based on the readability of the character evaluated by the evaluation means.

According to the eleventh aspect of the present invention, a computer is caused to calculate a color difference including each color and brightness of a character on a display screen and a background, and the color difference is calculated using a resolution characteristic indicating a resolution corresponding to the color difference. The resolution corresponding to the color difference is determined, the readability of the character is evaluated based on the relationship between the determined resolution and the size of the character, and the display is based on the readability of the evaluated character. The feature is that the recommended character size of the screen is displayed.

In the ninth and eleventh aspects of the invention, as in the fifth and seventh aspects, the color difference calculation process, the resolution determination process, and the readability of characters are evaluated. Then, the recommended character size on the display screen is displayed based on the readability of the evaluated character. This recommended character size is a character size that can obtain an evaluation equal to or higher than the evaluation of the readability of the character. This makes it possible to objectively present a character size that makes the character easier to read without depending on the subjectivity of the operator.

The invention according to claim 10 is the invention according to claim 9, wherein the recommended character size selecting means for selecting the recommended character size displayed by the recommended character size displaying means and the recommended character size selecting means are selected. Display screen conversion means for converting the display screen so as to obtain the recommended character size.

According to a twelfth aspect of the present invention, in the invention according to the eleventh aspect, the computer is caused to convert the display screen so as to have a recommended character size selected from the displayed recommended character sizes. Is characterized by.

According to the tenth and twelfth aspects of the invention, the recommended character size selecting means is operable in accordance with the operation of the operator.
Select a predetermined character size from the displayed recommended character sizes. Then, the display screen is converted to have the selected recommended character size. As a result, the character size of the display screen is converted into the predetermined character size, so that the operator can obtain the display screen in which the characters are easy to read without performing complicated operations.

The thirteenth aspect of the present invention comprises the brightness calculation device according to the first or second aspect and the readability evaluation device according to any one of the fifth, sixth, ninth and tenth aspects. .

According to the thirteenth aspect of the present invention, the upper limit value of the brightness is calculated by using the brightness calculating device, so that the upper limit of the brightness is not uncomfortable in consideration of the individual difference due to age and the difference in the background color. Find the value. Furthermore, by using the readability evaluation device, it is possible to objectively present the recommended color and the recommended character size of the character or the background without depending on the subjectivity of the operator. As a result, it is possible to improve the efficiency of the design work of the display screen while considering the visual environment and individual differences of the observer.

According to a fourteenth aspect of the present invention, an image display means for displaying an image having characters and a background is provided.
The brightness calculation device described above, and a control means for controlling the brightness of the display image displayed on the image display means so as not to exceed the upper limit value of the brightness calculated by the brightness calculation device.

According to the fourteenth aspect of the present invention, the luminance calculation device is used to obtain an upper limit value of the luminance which does not cause discomfort in consideration of individual differences due to age and differences in background color, and the calculated luminance is calculated. The brightness of the display image displayed on the image display means is controlled so as not to exceed the upper limit. This allows
The observer can see the image display means without feeling the glare that causes discomfort.

According to a fifteenth aspect of the present invention, in the invention according to the fourteenth aspect, the brightness calculation device further comprises an input means for inputting an age corresponding to the visual acuity, and the age correction coefficient calculation means is the input means. The age correction coefficient is calculated based on the age corresponding to the visual acuity input by.

According to the fifteenth aspect of the invention, it is preferable to use, as the age corresponding to the visual acuity, for example, a test result of how far a plurality of indices having different sizes can be seen, that is, a result of the visual acuity test. At this time, the age correction coefficient calculation means calculates the age correction coefficient based on the result of the visual acuity test as the age corresponding to the visual acuity. Then, the upper limit value of the brightness of the display screen is calculated using the age correction coefficient, and the brightness of the display image displayed on the image display means is controlled so as not to exceed the calculated upper limit value of the brightness. As a result, it is possible to eliminate the individual difference in visual characteristics due to age, control the brightness of the image display means, and eliminate the psychological resistance that the user's age is directly used.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment] In the first embodiment, a display screen designing apparatus 1 having the configuration shown in FIG. 1 will be described as an example. The display screen designing device 1 is suitable for an operator to design a display screen of an in-vehicle display of a navigation device according to individual differences of drivers.

Specifically, as shown in FIG. 1, the display screen designing apparatus 1 includes an interface 11 for inputting / outputting image data and the like, and a mouse 1 as a pointing device.
2, a keyboard 13 for inputting parameters for display screen setting, a hard disk drive 15 for storing operation programs and application programs, and an LCD (Liquid Crystal) for displaying operation screens and images in place of the in-vehicle display. Display) 1
6, and a microcomputer 20 for overall control,
Is equipped with.

When the sample image for the display screen is input, the interface 11 displays the sample image,
The data is supplied to the microcomputer 20 via the data bus 17. 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 to input the character size, the driver's age, the brightness (for example, the brightness outside the vehicle, the size of the LCD 16 (the solid angle viewed from the driver's position), etc.).

The hard disk drive 15 stores an operation program, an application program for designing a display screen, and the like. L
The CD 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 stores a CPU 21 that executes arithmetic processing for setting a display screen, a RAM 22 that is a data work area, and a control program of the CPU 21 and a predetermined table.
And OM23.

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, a screen position coefficient indicating a screen position coefficient P according to the installation position of the LCD 16 is displayed. A table, resolution characteristic data, a score table indicating the legibility of characters, and recommended color data for presenting recommended colors according to the scores are stored.

As shown in FIG. 2, the screen position coefficient table is a table for setting different coefficients for each installation position of the LCD 16. Specifically, the screen position coefficient P is the LCD
The installation position of 16 is "3.5" in the center part of the center console and "3.
1 ”, and“ 2.8 ”on the dashboard.

The resolution characteristic data is data showing a visual spatial frequency characteristic, specifically, a characteristic of resolution with respect to color difference. The resolution characteristic data shown in FIG. 3 indicates the characteristic in the daytime. In addition, since the resolution characteristic data generally differs depending on the age, the hard disk drive 15 has 23 years old, 30 years old, 40 years old, 50 years old, 60 years old,
The respective resolution characteristic data of 70 years old are stored.

Further, since the resolution characteristic data varies depending on the visual environment, the hard disk drive 15 has 23 years old, 30 years old, 40 years old at night as shown in FIG.
The resolution characteristic data of each of ages 50, 60, 70 is also stored. Note that the hard disk drive 15 stores resolution characteristic data for daytime and nighttime, but may also store resolution characteristic data for visual environments other than daytime and nighttime.

As shown in FIG. 5, 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 image to set a display screen which is easy to see, and therefore FIG.
The processing from step ST1 onward is performed.

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

In step ST2, the microcomputer 20 determines whether the age of the driver looking at the LCD 16 has been input by operating the mouse 12 or the keyboard 13, waits until the age is input, and the age is input. Then, the process proceeds to step ST3.

In step ST3, the microcomputer 20 calculates the upper limit value of the brightness of the sample image. Here, specifically, the subroutine from step ST11 to step ST14 shown in FIG. 7 is executed.

At step ST11, the microcomputer 20 calculates the equation (6) to obtain the basic luminance B ₀ [cd
/ M ² ], and the process proceeds to step ST12.

[0066]

[Equation 6]

Equation (6) is a reference "Brightness in Visual Field at Bor" that measures the pleasantness and unpleasantness of glare in lighting.
derline Between Comfort and Discomfort ”M. Luckies
Et al., Illuminating Eng., 650-670, 1949 is modified so that it can be applied to in-vehicle displays. That is, Expression (6) shows the visual characteristic of glare for the in-vehicle display.

F is the brightness outside the vehicle [cd / m ² ], Q
Is the size of the screen (the solid angle of the screen as seen from the driver position)
[Str] and P are screen position coefficients. Screen position factor P
Depends on the position where the LCD 16 is installed, and as shown in FIG. 2, "3.
5 "," 3.1 "at the top of the center console,
It is "2.8" on the dashboard. The brightness F outside the vehicle, the screen size Q, and the screen position coefficient P
Is preferably operated by operating the mouse 12 or the keyboard 13 in advance.

In step ST12, the microcomputer 20 calculates the equation (7) to correct the glare characteristic correction coefficient for age (hereinafter referred to as "age correction coefficient") K _A.
And shifts to step ST13. In addition, a is an age [year], and is a value input in step ST2.

[0070]

[Equation 7]

In step ST13, the microcomputer 20 determines the correlated color temperature t of the background color from the sample image.
[K], white correlated color temperature t _w [K] is extracted. Then, the equation (8) is calculated to obtain the correction coefficient (hereinafter, referred to as “color correction coefficient”) K _C of the glare characteristic for the color, and the process proceeds to step ST14.

[0072]

[Equation 8]

In step ST14, the microcomputer 20 causes the basic luminance B ₀ , the age correction coefficient K _A , and the color correction coefficient K _C obtained in steps ST11 to ST13.
The equation (9) is calculated by using the upper limit value B [cd
/ M ² ].

[0074]

[Equation 9]

When the microcomputer 20 obtains the upper limit value B of the display brightness, it exits this subroutine and proceeds to step ST4 shown in FIG.

As described above, the microcomputer 20
Calculates the basic brightness B ₀ based on the glare characteristic which is one of the visual characteristics, and multiplies the basic brightness B ₀ by the age correction coefficient K _A and the color correction coefficient K _C to obtain the driver's age and background. It is possible to calculate the display brightness that corresponds to the color and does not cause discomfort even at night.

In step ST4, the microcomputer 20 calculates a score indicating the readability of the character based on the image data of the sample image. The microcomputer 20 specifically executes the subroutine from step ST21 to step ST23 shown in FIG.

At step ST21, the microcomputer 20 determines from the sample image the color of the character (L ₀ , a ₀ , b ₀ ) and the background color (L ₁ , a ₁ ,
b ₁ ) is extracted, the color difference D is obtained by calculating the equation (10), and the process proceeds to step ST22.

[0079]

[Equation 10]

The color difference D is the contrast between the character and the background including both the color and the 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 formulas (11) to (13) ).

[0081]

[Equation 11]

In step ST22, the microcomputer 20 calculates the color difference D calculated in step ST21,
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 the visual environment and the age from the plurality of resolution characteristic data stored in the hard disk drive 15, refers to the selected resolution characteristic data, and based on the color difference. Then, the resolution is determined, and the process proceeds to step ST23.

For example, the visual environment is "night" and the age is "30".
When the age is "80" and the color difference is "80", the microcomputer 2
As shown in FIG. 3, 0 indicates “3” when the visual environment is “night”.
The resolution characteristic data of "0 years old" is selected, and the resolution of 0.01 [deg] corresponding to the color difference "80" is determined.

In step ST23, the microcomputer 20 refers to the rating table stored in the hard disk drive 15 and determines the rating based on the character size of the sample image and the resolution determined in step ST22. That is, the microcomputer 20
Determines which region the coordinate position specified by the resolution and the character size is in, and determines the score based on the region to which the coordinate position belongs.

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 proceeds to step ST5 shown in FIG.

As described above, the microcomputer 20
Determines the resolution corresponding to the color difference of the sample image with reference to the visual spatial frequency characteristics based on the visual environment (daytime / nighttime) and age, and determines the readability of the character from the relationship between the resolution and the character size. Can be evaluated. That is, it is possible to accurately evaluate the readability of a character by considering not only the character color and background color and the character size, but also individual differences such as the visual environment and age.

At step ST5, the microcomputer 20 displays an operation screen (not shown) on the LCD 16, and then proceeds to step ST6. Here, the operation screen displays the upper limit value B of the brightness calculated in step ST3, the score obtained in step ST4, and the values of the background color and the character color at that time (for example, red (R), green (G), Display each value of blue (B).

The operation screen has a background recommended color button for presenting a recommended background color, a character recommended color button for presenting a recommended character color, and a recommended character size for presenting a recommended character size. It has a button and a setting button for setting the background color and the character color of the sample image.

At step ST6, the microcomputer 20 determines whether or not the setting button on the operation screen displayed on the LCD 16 has been clicked. If so, the process proceeds to step ST9, and if not, to step ST7. Transition.

In step ST7, the microcomputer 20 determines whether any one of the recommended background color button and the recommended character color button has been clicked, and when any one of them has been clicked, the process proceeds to step ST8, and both of them are clicked. If not clicked, the process returns to step ST6.
In the following description, it is assumed that the background recommendation button is clicked.

In step ST8, the microcomputer 20 displays a plurality of recommended colors from evaluation 3 to evaluation 5, and determines one recommended color from these recommended colors. Here, specifically, step ST3 shown in FIG.
Execute subroutines 1 and below.

At step ST31, the microcomputer 20 sets "3" as the initial value of the rating n,
The process proceeds to step ST32.

At step ST32, the microcomputer 20 refers to the rating table shown in FIG. 5, 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 ST33.

In step ST33, the microcomputer 20 selects the resolution characteristic data that matches the visual environment and age of the driver from the resolution characteristic data shown in FIGS. Then, the range of chromaticity D corresponding to the range of resolution obtained in step ST32 is obtained by referring to the resolution characteristic data, and the process proceeds to step ST34.

In step ST34, the microcomputer 20 refers to the equations (10) to (13) described above, and the background color (L ₁ , a) that satisfies the range of the chromaticity D obtained in step ST33. ₁ , b ₁ ) is obtained, and the process proceeds to step ST35.

In step ST35, it is determined whether or not the score n is "5". If the score n is "5", the process proceeds to step ST37. If the score n is not "5", the process proceeds to step ST36. . In step ST36, the score n
Is incremented by 1, and the process returns to step ST32.

The microcomputer 20 performs the processing from step ST31 to step ST36 as described above.
By repeating this, the recommended colors for each of the grades 3 to 5 are obtained.

In step ST37, the microcomputer 20 reads the recommended color data indicating the background color (L ₁ , a ₁ , b ₁ ) obtained in step ST34 from the hard disk drive 15, and as shown in FIG.
The color palette is displayed on the LCD 16. 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 to click the desired color, the microcomputer 20 sets the clicked color as the background color, ends the subroutine processing, and returns to step ST5 shown in FIG.

Then, the microcomputer 20 has L
A new setting screen is displayed on the CD 16. The new operation screen displays the upper limit value B of the brightness calculated in step ST3, the score obtained in step ST4, the value of the first input character color, and the value of the background color set in step ST37.

On the other hand, when it is determined in step ST6 that the setting button has been clicked, in step ST9, 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. Give. The microcomputer 2
In the case of 0, if the background color and the character color have not changed since the input of the sample image, the image processing may not be performed. Further, the microcomputer 20 may perform image processing on the sample image so that the brightness becomes the upper limit value D when the brightness of the sample image has already exceeded the upper limit value D of the brightness obtained in step ST3.

Then, the microcomputer 20 displays the image-converted sample image on the LCD 16. As a result, the operator can confirm whether the sample image is too dazzling or whether the characters of the sample image are easy to see.

As described above, the display screen designing apparatus 1 can set the upper limit value of the brightness for the sample image consisting of the character and the background so as not to make the driver feel uncomfortable based on the glare characteristic. Display screen design device 1
In particular, since it is possible to set the upper limit value of the brightness according to the age of the driver and the visual environment, the display image can be made to correspond to each driver.

Further, the display screen design apparatus 1 determines the resolution based on the spatial frequency characteristics based on the visual environment and age,
The readability of the character can be objectively presented to the operator by determining the score indicating the readability of the character from the relationship between the resolution and the character size.

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

In the present embodiment, the processing from step ST31 to step ST37 has been described by taking the case where the background recommendation button is clicked as an example, but the same applies when the character recommendation button is clicked. Needless to say, the processing from step ST31 to step ST37 can be executed.

Although the case of converting the color of the character or background to the recommended color has been described as an example in FIGS. 6 and 9, the character size of the display screen may be converted to the recommended character size.

Specifically, the microcomputer 20
Determines whether the recommended character size button on the operation screen has been clicked, and when clicked, displays a plurality of recommended character sizes corresponding to evaluations 3 to 5 on the LCD 16.

For example, the resolution of the sample image is 0.037.
If it is [deg], the microcomputer 20
Refers to the rating table shown in FIG. 5 and displays a character size of 1.0 [deg] or more as a recommended character size on the LCD 16.
To display. This makes it possible to objectively present a character size that makes the character easier to read without depending on the subjectivity of the operator.

When the predetermined recommended character size is selected by the mouse 12, the microcomputer 20
Convert the characters in the sample image so that it has the recommended character size. As a result, the character size of the display screen is converted into the predetermined character size, so that the operator can obtain the display screen in which the characters are easy to read without performing complicated operations.

[Second Embodiment] Next, a second embodiment of the present invention will be described in detail with reference to the drawings. In the second embodiment, the navigation device 50 having the configuration shown in FIG. 11 will be described as an example. The navigation device 50 according to the present embodiment automatically sets the display brightness based on the glare characteristics and displays the route information and the like.

Specifically, as shown in FIG. 11, the navigation device 50 includes an operation button 51 for inputting parameters such as a driver's visual acuity and a GP (not shown).
G via S (Global Positioning System) antenna
A GPS receiving circuit 52 for receiving a PS signal, a brightness sensor 53 for detecting external brightness, a DVD drive 54 for reading map information recorded on a DVD disc, and a DV.
An in-vehicle display 55 that displays the map information and the like read from the D drive 54, and a microcomputer 60 that performs all controls including route search and setting of display brightness of the in-vehicle display 55 are provided.

The microcomputer 60 comprises a CPU 61 for executing arithmetic processing for setting a display screen, a RAM 62 as a data work area, and a ROM 63 in which a control program for the CPU 61 is stored.

The microcomputer 60 reads the map information from the DVD drive 54 and sets the route from the present location to the destination according to the operation setting of the operation button 51. Further, the microcomputer 60 calculates the current position of the own vehicle based on the GPS signal input to the GPS receiving circuit 52, and controls to display the current position on the in-vehicle display 55 together with the map information.

In the ROM 63, in addition to the control program of the CPU 61, as shown in FIG. 12, visual acuity characteristic data indicating the characteristic of visual acuity with respect to age is stored. The visual acuity characteristic data is data that statistically shows changes in visual acuity with age.

In the navigation device 50 configured as described above, the microcomputer 60 executes the processing of step ST41 and subsequent steps shown in FIG. 13 in order to automatically set the brightness of the display screen of the in-vehicle display 55. .

At step ST41, the microcomputer 60 determines the age of the driver's eyes. Here, the driver performs a visual acuity test in advance using a visual acuity test table as shown in FIG. 14, for example. And operation button 5
Operate 1 to input the visual acuity.

When the visual acuity is input, the microcomputer 60 refers to the visual acuity characteristic data stored in the ROM 63, determines the age a ₁ of the eye corresponding to the input visual acuity, and proceeds to step ST42. To do.

At step ST42, the microcomputer 60 calculates the basic luminance B ₀ by calculating the equation (14) using the external luminance detected by the luminance sensor 53.
Then, the process proceeds to step ST43.

[0121]

[Equation 12]

In the equation (14), F ₁ is the brightness outside the vehicle detected by the brightness sensor 53 [cd / m ² ].
Is shown. Q is the size of the in-vehicle display 55 (solid angle of the screen seen from the driver position) [str],
P is a screen position coefficient, and these values are preset.

At step ST43, the microcomputer 60 calculates the equation (15) to calculate the age correction coefficient K _A '
, And the process proceeds to step ST44.

[0124]

[Equation 13]

Note that a ₁ is the age [years] of the eyes determined in step ST41.

In step ST44, the microcomputer 60 determines the correlated color temperature t of the background color from the sample image.
[K], white correlated color temperature t _w [K] is extracted. Then, the equation (16) is calculated to obtain the color correction coefficient K _C ,
The process proceeds to step ST45.

[0127]

[Equation 14]

At step ST45, the microcomputer 60 causes the basic luminance B ₀ , the age correction coefficient K _A 'and the color correction coefficient K obtained at steps ST42 to ST44.
Equation (17) is calculated using _C, and the upper limit value B ′ of the display brightness is calculated.
After obtaining [cd / m ² ], the process proceeds to step ST46.

[0129]

[Equation 15]

At step ST46, the microcomputer 60 controls the light emission of the backlight 55a of the vehicle-mounted display 55 so as not to exceed the upper limit value B'of the display brightness calculated at step ST45, and the series of processing is terminated. To do.

As described above, the navigation device 50
Calculates the age correction coefficient K _A ′ using the age of the eyes instead of the actual age, and further calculates the upper limit value B ′ of the display brightness to eliminate individual differences in visual characteristics, which is optimal for drivers. The brightness can be set. Further, the navigation device 50 can eliminate the psychological resistance to input the actual age by using the visual acuity tested by the visual acuity test instead of the actual age.

The present invention is not limited to the above-described embodiments, but can be modified as follows. For example, the microcomputer 60 uses the step S
The age correction coefficient K _A may be calculated in the same manner as in the first embodiment by omitting the step T41. That is, in step ST43, the actual age a of the driver may be used instead of the age a'of the eye in Expression (15).

[0133]

According to the brightness calculation device and the brightness calculation program of the present invention, the basic brightness of the display screen based on the visual characteristics of the glare, the age correction coefficient according to the age, the background color and the white correlated color. By calculating the upper limit value of the brightness of the display screen based on the color correction coefficient based on the temperature, the upper limit value of the brightness that does not become unpleasant is calculated in consideration of individual differences due to age and differences in background color be able to.

According to the readability evaluation apparatus and the readability evaluation program of the present invention, the color difference including the color and brightness of each of the character and the background is calculated, and the resolution corresponding to the calculated color difference is determined. Then, the readability of the character is evaluated based on the relationship between the determined resolution and the size of the character, and based on the readability of the evaluated character, the recommended color of the character or background of the display screen. By displaying, it is possible to objectively present a recommended color that makes the characters easier to read without depending on the subjectivity of the operator.

Further, according to the readability evaluation apparatus and readability evaluation program of the present invention, the color difference including the color and brightness of each of the character and the background is calculated, and the resolution corresponding to the calculated color difference is calculated. The readability of the character is evaluated based on the determined resolution and the relationship between the character size and the recommended character size of the display screen based on the readability of the evaluated character. By displaying the character size, it is possible to objectively present a character size that makes the character easier to read, without depending on the subjectivity of the operator.

According to the display screen designing apparatus of the present invention,
The brightness calculation device is used to calculate the upper limit of brightness, the readability evaluation device is used to evaluate the readability of the characters, and the recommended color and recommended character size are presented, thereby providing the visual environment and the individual observer. The efficiency of the design work of the display screen can be improved while considering the difference.

According to the image display device of the present invention, by controlling the brightness of the display image displayed on the image display means so as not to exceed the upper limit value of the brightness calculated by the brightness calculation device, age and background It is possible to display a comfortable image in which glare is suppressed in consideration of color.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a display screen designing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a screen position coefficient table stored in a hard disk drive.

FIG. 3 is a diagram showing resolution characteristic data in the daytime.

FIG. 4 is a diagram showing resolution characteristic data at night.

FIG. 5 is a diagram showing a score table.

FIG. 6 is a flowchart of a main routine for explaining the operation procedure of the microcomputer.

FIG. 7 is a flowchart of a subroutine for explaining the operation procedure of the microcomputer.

FIG. 8 is a flowchart of a subroutine for explaining the operation procedure of the microcomputer.

FIG. 9 is a flowchart of a subroutine for explaining the operation procedure of the microcomputer.

FIG. 10 is a diagram showing an example of a color palette showing recommended colors of characters and a background.

FIG. 11 is a block diagram showing a configuration of a navigation device according to a second embodiment of the present invention.

FIG. 12 is a diagram showing visual acuity characteristic data.

FIG. 13 is a flowchart for explaining an operation procedure of the microcomputer.

FIG. 14 is a diagram showing an example of a visual acuity test table.

[Explanation of symbols] 1 Display screen setting device 20,60 microcomputer 16 LCD 50 navigation equipment 55 In-vehicle display

Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) G09G 5/26 650 G09G 5/26 650B (72) Inventor Kazunori Higuchi Daikaku Nagakute, Aichi-gun, Aichi Prefecture 41 No.1 Toyota Central Research Institute Co., Ltd. (72) Inventor Kazuhiko Sugiyama 1 41, Yokoshiro, Nagakute-cho, Aichi-gun, Aichi-gun 1 In Toyota Central Research Institute Co., Ltd. (72) Inventor Koji Kishi 1 Toyota-cho, Toyota-shi, Aichi Address Toyota Motor Co., Ltd. (72) Inventor Kanamori, etc. 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. F Term (reference) 2H093 NA79 NC90 ND02 5C082 AA01 AA22 BA02 BA34 BA35 BB51 CA11 CA12 CA33 CA34 CB05 DA71 DA87 MM09 MM10

Claims (15)

[Claims] 1. A basic brightness calculation means for calculating a basic brightness of a display screen based on visual characteristics of glare, an age correction coefficient calculation means for calculating an age correction coefficient according to age, and a background color of the display screen. A color correction coefficient calculating means for calculating a color correction coefficient based on a white color, a basic luminance calculated by the basic luminance calculating means, an age correction coefficient calculated by the age correction coefficient calculating means, and the color correction coefficient calculation A brightness calculation device, comprising: a brightness calculation means for calculating an upper limit value of the brightness of the display screen based on the color correction coefficient calculated by the means. 2. The basic brightness calculation means uses at least one of an installation position of the display screen, a brightness around the display screen, and a solid angle of the display screen with respect to a predetermined position,
The brightness calculation device according to claim 1, wherein a basic brightness of the display screen is calculated. 3. A computer calculates a basic brightness of a display screen based on visual characteristics of glare, an age correction coefficient according to age, and a color correction coefficient based on a background color and white of the display screen. A brightness calculation program for calculating an upper limit value of the brightness of the display screen based on the basic brightness, the age correction coefficient, and the color correction coefficient. 4. The computer is provided with an installation position of the display screen, a brightness around the display screen,
At least one of the solid angles of the display screen with respect to a predetermined position
The brightness calculation program according to claim 3, wherein the basic brightness of the display screen is calculated using one of the two. 5. A color difference calculation means for calculating a color difference including a color and brightness of a character and a background of a display screen, and a resolution characteristic indicating a resolution corresponding to the color difference are calculated by the color difference calculation means. Resolution determining means for determining the resolution corresponding to the color difference, and an evaluating means for evaluating the readability of the character based on the relationship between the resolution determined by the resolution determining means and the size of the character, and the evaluating means. Based on the readability of the characters evaluated by
A readability evaluation device comprising: a recommended color display unit that displays a recommended color of the characters or the background of the display screen. 6. A recommended color selection means for selecting a recommended color of a character or background displayed by the recommended color display means, and the display so that the recommended color of the character or background selected by the recommended color selection means is displayed. The readability evaluation apparatus according to claim 5, further comprising: a display screen conversion unit that converts a screen. 7. A resolution corresponding to the calculated color difference is calculated by causing a computer to calculate a color difference including each color and brightness of a character and a background of a display screen and using a resolution characteristic indicating a resolution corresponding to the color difference. The readability of the character is evaluated based on the relationship between the determined resolution and the size of the character, and the readability of the character is evaluated based on the readability of the character. A readability evaluation program characterized by displaying recommended colors. 8. The display screen is converted by the computer so that the recommended color of the displayed character or background is the recommended color of the selected character or background. Readability evaluation program. 9. A color difference calculation means for calculating a color difference including a color and brightness of each of a character and a background of a display screen, and a resolution characteristic showing a resolution corresponding to the color difference, which are calculated by the color difference calculation means. Resolution determining means for determining a resolution corresponding to the color difference, an evaluating means for evaluating the readability of the character based on the relationship between the resolution determined by the resolution determining means and the size of the character, and the evaluating means. Based on the readability of the characters evaluated by
A readability evaluation apparatus comprising: a recommended character size display means for displaying a recommended character size on the display screen. 10. A recommended character size selecting means for selecting the recommended character size displayed by the recommended character size displaying means, and converting the display screen so as to have the recommended character size selected by the recommended character size selecting means. The readability evaluation apparatus according to claim 9, further comprising: 11. A resolution corresponding to a calculated color difference is calculated by causing a computer to calculate a color difference including each color and brightness of a character and a background of a display screen and using a resolution characteristic indicating a resolution corresponding to the color difference. The readability of the character is evaluated based on the relationship between the determined resolution and the size of the character, and the recommended character size of the display screen is determined based on the readability of the evaluated character. Readability evaluation program characterized by displaying. 12. The readability evaluation program according to claim 11, wherein the computer causes the display screen to be converted so that the recommended character size is selected from the displayed recommended character sizes. . 13. A display screen designing device comprising: the brightness calculation device according to claim 1 or 2; and the readability evaluation device according to any one of claims 5, 6, 9, and 10. 14. An image display means for displaying an image having characters and a background, the brightness calculation device according to claim 1 or 2, and the brightness calculation device so as not to exceed an upper limit value of the brightness calculated by the brightness calculation device. An image display device comprising: a control unit that controls the brightness of a display image displayed on the image display unit. 15. The brightness calculation device further comprises input means for inputting an age according to visual acuity, and the age correction coefficient calculation means corrects age based on the age according to visual acuity input by the input means. The image display device according to claim 14, wherein a coefficient is calculated.