JP2002041025A - Image display device and image display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device that makes lines not to be seen thinner even though dark characters and lines are displayed in a bright background. SOLUTION: It is provided with smoothing means 5-7 that perform smoothing processing selectively to image data to be inputted, an image detection means 4 that discriminates a dark part and a bright part of an image from the image data to be inputted and at the same time, generates a control signal that selects the smoothing processing to be performed to image data of the bright part neighbouring to the dark part and sends it to the smoothing means 5-7, and a display means 8 that displays an image based on the image data outputted from the smoothing means 5-7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display apparatus and an image display method for digitally performing image processing on input image data and displaying the digital image data. The present invention relates to an image display device and an image display method for performing an outline correction process for making it easier to see.

[0002]

2. Description of the Related Art Conventionally, liquid crystal: liquid crystal display (LCD), plasma display panel: plasma display panel (PDP), light emitting diode:
2. Description of the Related Art Image display devices such as a light emitting diode (LED) and an electroluminescence (EL) panel are known. Further, these image display elements (cells) are, for example, red (red: R) and green (green: red).
2. Description of the Related Art There is known an image display apparatus using a matrix-type display device in which cells of three primary colors of G) and blue (blue: B) are set as one set and a number of the sets are arranged.

FIG. 28 is a block diagram showing a configuration of a conventional image display device. The image display device 101 in FIG.
R (red: first color), G (green: second color), B (blue: third color)
The image data SR1, SG1, and SB1 of the analog signals input for each of the three primary colors are sampled at a predetermined frequency to convert them into digital signal image data (SR2, SG2, and SB2). / Digital (A / D) conversion means 1 to 3 and image data (SR
2, SG2, and SB2) are subjected to a smoothing process using a filter described later to generate image data SR3, SG3, and SB3.
, And image data SR3, S
The display unit 8 is configured to display an image based on G3 and SB3.

[0004] Here, the smoothing means 5 to 7 are inserted for the reason described below. 2. Description of the Related Art In recent years, for example, in document creation using a personal computer (PC), a bright portion (for example, white background) and a dark portion (for example, white background) in a display image are used for associating lines and characters on actual paper. In many cases, black lines and characters are used.

In general, a bright color portion in a display image appears to expand more than it actually is. Therefore, for example, a white point (or line) is formed on a black background even at the same point of one pixel. When displaying the image, and when displaying a black dot (or line) on a white background, the white dot is recognized (expanded) greatly by the user, and conversely, the black dot is used. Is perceived small (shrinking) by the person.

FIG. 29 (a) is a diagram showing a luminance distribution for each cell when a white line image is displayed on a black background on the display means. FIG. FIG. 9 is a diagram showing a luminance distribution for each cell when a black line image is displayed in the background of FIG.

The horizontal axis of FIGS. 29A and 29B indicates the horizontal position of the display means 8 on the screen since the conventional image display device 101 uses a matrix type display device. R0a to R9a are red cells of three primary colors, G0
a to G9a indicate three primary color green cells, B0a to B9a indicate three primary color blue cells, and from the left red (R), green (G),
One cell of blue (B) is arranged in order, and three cells are arranged to form one set (ST). One ST corresponds to one pixel of the display means. The vertical axis is luminance.

[0008] In the case of FIG.
Since the case where the white point (or line) of the pixel is displayed is shown, the white point (or line) is recognized by the user by expanding. On the other hand, FIG. 29B shows a case where a black point (or line) of one pixel is displayed on a white background, and the black point (or line) is recognized as contracted by the user. .

When the images shown in FIGS. 29A and 29B are displayed on a conventional image display device, FIG.
As described above, characters and lines appear thicker than they actually are. In FIG. 29B, characters and lines appear thinner than they actually are. Therefore, at the time of the display of FIG.
Although a thin line looks like a bold line, it is usually recognizable although there are inconveniences such as making it difficult to see fine characters and the like. However, at the time of the display in FIG. 29B, the thin line looks even thinner, so that characters, lines, and the like may be difficult to see and may not be recognized.

In recent years, the resolution of a display device of a PC has been increased due to a desire to increase the display content per display screen in order to increase the work efficiency of document creation and the like. There is a tendency. As the resolution of the display device increases, the size of one pixel with respect to the screen size becomes relatively smaller. Then, when a black line or a black character is displayed on a white background as in the case of the display of FIG. 29B, the character or the line becomes more visible to the user.

Therefore, the outline of characters and lines is corrected using a smoothing filter, so that the white and black steps of the outline of the characters and lines to be displayed are smoothed, and the black lines and black characters on a white background are smoothed. It was conceived not to look too thin.

FIG. 30 is a diagram showing characteristics of a smoothing filter used for conventional contour correction. The horizontal axis of FIG.
As in FIG. 29, the horizontal position on the screen of the display means 8 is shown. From left, one cell of each of red (R), green (G), and blue (B) is arranged in order and three cells are arranged to form one set (ST). And 1
ST corresponds to each one pixel of the display means, and n represents an arbitrary positive integer. The vertical axis is luminance.

The filter characteristic in the smoothing means 5 for smoothing the red (first color) image data SR2 is FR1, and the filter characteristic in the smoothing means 6 for smoothing the green (second color) image data SG2. The filter characteristic is FG1, and the filter characteristic in the smoothing means 7 for smoothing the blue (third color) image data SB2 is FB1.

For example, a pixel at STn + 1 is a white point (bright portion).
When the pixels STn and STn + 2 are black points (dark parts), the luminance of each image data in STn + 1 (bright parts) is smoothed and reduced by the filter characteristics, and STn
And the brightness of each image data of STn + 2 (dark part) is smoothed by the filter characteristics and increases.

FIGS. 31 (a) and 31 (b) show the luminance distribution of the image shown in FIG. 29 which has been smoothed using the smoothing filter shown in FIG. R0b to R9b and R1c to R8c are red cells of three primary colors, and G0b to G0b.
9b and G1c to G8c are green cells of three primary colors, B0
b to B9b and B1c to B8c indicate blue cells of three primary colors, and other settings are the same as those in FIG.

FIG. 31A shows the processing result when image data for displaying a white point on a black background in FIG. 29A is smoothed. ST2 white point (R2b, G2b, B2
b) decreases by (R2c, G2c, B2c), and simultaneously ST1 (R1) on both sides of ST2.
b, G1b, B1b) and ST3 (R3b, G3b, B
3b) The black background (black point) luminance is (R1c, G1c,
B1c) and (R3c, G3c, B3c).

FIG. 31B shows a processing result when image data for displaying a black point in the white background in FIG. 29B is smoothed. ST7 black spots (R7b, G7
b, B7b) are respectively (R7c1 + R7c2, G7
c1 + G7c2, B7c1 + B7c2), and simultaneously ST6 (R6b, G6) on both sides of ST7.
b, B6b) and ST8 (R8b, G8b, B8b) have reduced white background luminance by (R6c, G6c, B6c) and (R8c, G8c, B8c), respectively. In particular, the increase in the brightness of the black point in ST7 is doubled by adding the smoothing processes in ST6 and ST8 on both sides of ST7.

In a conventional image display method using contour correction,
As described above, the white point and the black point are similarly smoothed, that is, the brightness of the black point is raised at the same time as the brightness of the white point is reduced, so the display of black lines and black characters in the white background becomes invisible Although the situation can be improved, the sharpness of not only the black lines and black characters on the white background but also the white lines and white characters on the black background has deteriorated. In particular, in the case of a black line or a black character in a white background, the increase in luminance due to the smoothing process is doubled, so that the degree of sharpness deterioration is increased.

[0019]

In the conventional image display apparatus which does not perform the contour correction as described above, a dark character or a line in a light background such as a black line or a black character in a white background is used. There is a problem that the line looks thin when is displayed.

Further, in order to solve the above-mentioned problem, when the contour correction is performed by using the smoothing means (filter), if the contour correction is not necessary, such as a white line or a white character in a black background or the like,
There is a problem that bright characters and lines in a dark background are also smoothed.

When the contour correction is performed using the smoothing means, the luminance of dark characters and lines on a light background increases, and the luminance of bright characters and lines on a dark background decreases. As a result, the sharpness deteriorates as a result. In particular, there is a problem that the sharpness of a dark character or a line portion in a light background is greatly deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems. Even if dark characters or lines are displayed on a light background, the lines do not look thin, and the lines on the dark background do not appear. It is an object of the present invention to provide an image display apparatus in which bright characters and lines are not smoothed and the sharpness of characters and lines does not deteriorate.

[0023]

In order to achieve the above-mentioned object, an image display apparatus according to the present invention has a smoothing means for selectively performing smoothing processing on input image data. Image detecting means for determining a dark portion and a light portion of an image from input image data, generating a control signal for selecting a smoothing process to be applied to image data of a light portion adjacent to the dark portion, and sending the control signal to the smoothing portion And display means for displaying an image based on the image data output from the smoothing means.

According to a second aspect of the present invention, in the image display device according to the first aspect, when data for each of the three primary colors is obtained from the input image data, the smoothing means performs the processing for the three primary colors. The image detecting means is provided so that the smoothing process can be selectively performed on the data for each color individually and selectively by the control signal, and the image detecting means individually controls the data for each color of the three primary colors. A signal is generated and sent to a corresponding smoothing means.

According to a third aspect of the present invention, in the image display device according to the second aspect, when a luminance signal is obtained from the input image data together with data for each of the three primary colors, the image detecting means includes: A control signal is generated for each of the three primary colors based on the luminance signal, and is sent to a corresponding smoothing means.

According to a fourth aspect of the present invention, in the image display device according to any one of the first to third aspects, the image detecting means determines a dark portion and a bright portion of an image from input image data, and When the contour of the image can be detected and the image adjacent to the contour of the image is a bright portion, a control signal for selecting a smoothing process to be applied to the image data of the bright portion is generated and sent to the smoothing means. It is characterized by the following.

According to a fifth aspect of the present invention, in the image display device according to any one of the first to third aspects, the image detecting means determines a dark portion and a bright portion of an image from input image data, and A control signal for detecting that a dark portion of an image is equal to or less than a predetermined width, and selecting a smoothing process to be performed on image data of a bright portion of an image adjacent to the dark portion of the image when the dark portion of the image is equal to or less than a predetermined width. Is generated and sent to the smoothing means.

According to a sixth aspect of the present invention, in the image display device according to any one of the second to fifth aspects, the smoothing means adjusts a characteristic of a filter for performing a smoothing process for each of the three primary colors. It is characterized by changing.

According to a seventh aspect of the present invention, in the image display device according to the first aspect, when a luminance signal is obtained from the input image data together with data for each of the three primary colors, the smoothing means includes It is provided so that a smoothing process can be selectively performed on the luminance signal by a control signal, and the image detecting means generates and sends the control signal for the luminance signal.

[0030] The image display method according to the present invention includes a step of detecting a dark part of an image from input image data, and a step of detecting a dark part of the image when the image data is detected. A step of not performing a smoothing process; a step of detecting a bright portion of the image from the input image data; and a step of performing smoothing on the image data when image data serving as a bright portion of the image is detected. And a step of repeating the above steps until the image data is completed.

According to a ninth aspect of the present invention, in the image display method according to the eighth aspect, in the step of detecting image data serving as a bright portion of the image, the image data is further adjacent to a contour portion. Only in this case, a filter for smoothing the image data is selected.

According to a tenth aspect of the present invention, in the image display method according to the eighth aspect, in the step of detecting image data which is a bright portion of the image, the image data is further added to a dark portion having a predetermined width. Only when adjacent, a filter for smoothing the image data is selected.

The present invention according to claim 11 is the invention according to claims 8 to 10
In the image display method according to any one of the above, in the step of detecting image data that is a bright portion of the image, a filter having different characteristics for each of the three primary colors is selected.

The present invention of claim 12 is the invention of claims 8 to 10
5. The image display method according to claim 1, wherein in the step of detecting image data that is a bright portion of the image, a filter for smoothing a luminance signal is selected.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. Embodiment 1 FIG. FIG. 1 is a block diagram illustrating a configuration of an image display device according to a first embodiment of the present invention, and FIGS. 2 to 4 are block diagrams illustrating another configuration example of the image display device of FIG. In FIGS. 1 to 4, portions having the same functions as those of the conventional image display device 101 shown in FIG. 28 are denoted by the same reference numerals, and redundant description will be omitted.

The image display device 8 of the first embodiment shown in FIG.
1 mainly differs from the conventional image display apparatus 101 shown in FIG. 28 in that the outputs SR2 and SG of the A / D converters 1 to 3 are different.
2, control signals CR1, CG1, CB for selecting filters in the smoothing means 5-7 while SB2 is input.
1 is added to the corresponding smoothing means 5 to 7 respectively, and a plurality of smoothing means 5 to 7 having different characteristics including those not performing the smoothing process are included. And a selection means such as a switch for switching the filter. Also, regarding the internal configuration of the image detecting means 4 and the smoothing means 5 to 7,
This will be described later with reference to FIGS.

The image display device 82 of FIG. 2 shows a configuration in which the input image data is a luminance signal and a chrominance signal. In the image display device 81 of FIG. 1, the input image data has three primary colors (SR1, S1).
G1 and SB1) are two signals of a luminance signal SY1 and a chrominance signal SC1. Therefore, the A / D converter also receives the analog signal luminance signal SY1 and outputs the digital signal luminance signal SY2.
A / D in which the D conversion means 9 and the color signal SC1 of the analog signal are input and the color signal SC2 of the digital signal is output
There are two conversion means 10. Also, the luminance signal SY
2 and a matrix means 11 which receives the color signal SC2 and outputs digital RGB outputs (SR2, SG2, SB2). However, the image display device 8 of FIG.
2, the internal configuration of the image detecting means 4 and the smoothing means 5 to 7 is the same as that of the image display device 81 shown in FIG.

The image display device 83 shown in FIG. 3 shows a configuration in which the input image data is a composite signal SP1 of a luminance signal and a chrominance signal. In the image display device 81 shown in FIG. SG1, SB1) is a composite signal SP1 of a luminance signal and a chrominance signal. Therefore, the A / D converter also receives an analog composite signal SP1 and outputs a digital composite signal SP2.
Only one conversion means 12 is provided. Further, the luminance signal SY2 and the chrominance signal SC2 are converted from the composite signal SP2.
And a digital RGB output (SR) which receives a luminance signal SY2 and a chrominance signal SC2 as input.
2, SG2, and SB2). However, also in the image display device 83 of FIG. 3, the internal configuration of the image detection means 4 and the smoothing means 5 to 7 is the same as that of the image display device 81 shown in FIG.

In the image display devices 81 to 83 shown in FIGS. 1 to 3 described above, in order to correct the outline of the image displayed on the display means 8, each format (three primary colors, luminance signal / The image data of the color signal and the composite signal are sampled at a predetermined frequency, converted into three primary color image data of a digital signal, and the filters in the smoothing means 5 to 7 are used by using the three primary color image data of the digital signal. The method of outputting the control signals CR1, CG1, and CB1 for selection to the corresponding smoothing means 5 to 7 has been described.
In the present embodiment, the input is not limited to an analog signal, and may be applied to, for example, a case where digital image data is input to the display unit 8.

FIG. 4 is a block diagram showing a configuration of an image display apparatus in which digital data is input in the first embodiment. In the image display device 83 of FIG. 4, reference numeral 15 denotes an input terminal of red digital image data SR2 which is a first color forming three primary colors, and 16 denotes green digital image data which is a second color forming three primary colors. SG2 input terminal, 17
Is an input terminal for blue digital image data SB2, which is the third color of the three primary colors. Further, in the image display device 83, the input image data in the image display device 81 in FIG. 1 is analog three primary colors (SR1, SG1, SB1), but is digital three primary colors (SR1, SG1, SB1). Has become. Therefore, the A / D converter is not necessary because it is originally a digital signal. However, the configuration for executing the processing after the digital image data SR2, SG2, and SB2 is the same as that of the image display device 81 in FIG. . Therefore, also in the image display device 84 of FIG. 4, the internal configuration of the image detecting means 4 and the smoothing means 5 to 7 is the same as that of FIG.
Is the same as the image display device 81 shown in FIG.

FIG. 5 is a diagram showing the internal configuration of the image detecting means 4 shown in FIGS. The image detecting means 4 includes three comparing means 21, 23, 25 comprising, for example, comparators corresponding to each of the three primary color image data of the digital signal, and a threshold storing means 22 comprising, for example, memory, etc.
24, 26, and a control signal generating means 27, such as a microprocessor, for generating control signals CR1, CG1, CB1 from the comparison results of the comparing means 21, 23, 25.

In the above description of FIG. 5, the configuration in the case where the image data input to the image detecting means 4 is the three primary colors of the digital signal has been described. The image display device 81 in which the three primary colors of the analog signal shown are input and converted to digital is also used in FIG.
The same applies to the image display device 82 in which the analog luminance signal SY1 and the chrominance signal SC1 are input and converted to digital, as shown in FIG. 3, and the image display device 83 in which the analog composite signal SP1 is converted to digital as shown in FIG. Further, the image display device 82 of FIG. 2 and the image display device 83 of FIG.
If the input image data to each of the image display devices 82 or 83 is a digital signal, the digital image data is input instead of the illustrated A / D conversion means (9, 10 or 12). Alternatively, an input terminal (not shown) may be provided.

Each digital image data SR2, SG2, S
B2 is input to one input unit of each of the comparison units 21, 23, and 25. Threshold value storage means 22, 24, 26 are connected to the other input section of each of the comparison means 21, 23, 25, and each of the digital image data SR2, SG2, SB
A threshold value corresponding to 2 is input. Each comparing means 21,
In 23 and 25, each digital image data SR2, SG
2, a comparison process between SB2 and the storage contents of the threshold value storage means 22, 24, 26 is performed, and the comparison result is input to the control signal generation means 27. The control signal generation unit 27 makes a determination based on a comparison result of each of the comparison units 21, 23, and 25 based on a preset value, a value obtained by performing an arithmetic process, or the like, and the like.
Control signal generation means 27 sends control signals CR1, CG1, and CB1 for selecting a smoothing process (filter) to the corresponding smoothing means 5 to 7, respectively.

FIG. 6 is a diagram showing the internal configuration of the smoothing means 5 shown in FIGS. The input signals and the output signals of the smoothing means 6 and 7 are different from each other, but since the internal configuration is the same as that of the smoothing means 5, duplicate description will be omitted.

The smoothing means 5 includes a selection means 31 which is, for example, a one-input / two-output switch, and two filters (first filter means 32, Second filter means 33)
It consists of.

In the smoothing means 5, the red image data SR 2 of the digital primary color signal is input to the selection means 31. At this time, the output of the selecting means 31 is controlled by the control signal CR1 output from the control signal generating means 27 of the image detecting means 4 so that one of the two outputs is selected. The image data SR2 is input to the filter unit selected by the selection unit 31, and an output processed by the filter characteristics is output to the display unit 8 as image data SR3. It should be noted that, as the filter characteristics in this case, the filter characteristics in the case where the smoothing is not performed can be selected. That is, it is possible to select to output the input image data SR2 or the like as SR3 without performing the smoothing processing (filter processing).

FIG. 7 is a diagram showing an example of a luminance distribution in which image data before a smoothing process including a boundary (outline) between a dark portion and a bright portion is displayed on the display means 8 without smoothing.
FIG. 7A is a diagram illustrating a luminance distribution of each cell when an image having a bright portion on the left side and a dark portion on the right side is displayed, and FIG.
FIG. 4 is a diagram showing a luminance distribution of each cell when an image of a dark part is displayed on the left side and a bright part is displayed on the right side. 29 and FIG. 31, the vertical axis indicates the luminance and the horizontal axis indicates the horizontal position on the screen of the display means 8. R0e to R9e indicate red cells of three primary colors, G0e to G9e indicate green cells of three primary colors, and B0e to B9e indicate blue cells of three primary colors.

In FIG. 7 (a), the image detecting means 4 sets ST0 (R0), which is a set of three primary color cells corresponding to one pixel.
e, G0e, B0e), ST1 (R1e, G1e, B1)
e) and ST2 (R2e, G2e, B2e) are determined as bright parts, and ST3 (R3e, G3e, B3e), ST3
4 (R4e, G4e, B4e) is determined to be a dark part.

On the other hand, in FIG.
Are ST8 (R8e, G8e, B8e), ST9 (R9
e, G9e, B9e) are determined as bright parts, and S
T5 (R5e, G5e, B5e), ST6 (R6e, G5e
6e, B6e) and ST7 (R7e, G7e, B7e) are determined as dark portions.

As a bright part of the image adjacent to a dark part of the image, ST2 in FIG.
(R2e, G2e, B2e), and in FIG. 7B, ST8 (R8e, G8e, B8e) is detected. The image detecting means 4 performs smoothing means 5 based on the detection result.
Control signals CR1, CG1, CB1 for each of 6, 7
Is generated and output.

In the present embodiment, the control signals CR1 and CG of the image detecting means 4 are applied to the respective image data shown in FIG.
1. Based on CB1, the smoothing means 5, 6, 7 selectively perform a smoothing process. This makes it possible to selectively perform the smoothing process only on the bright part of the image adjacent to the dark part of the image at the boundary between the light part and the dark part of the image, so that dark characters and lines are displayed on a light background. Even if the lines do not look thin, bright characters and lines in a dark background are not smoothed, and furthermore, the sharpness of the characters and lines can be prevented from deteriorating.

The operation of smoothing an image based on the control signal output from the image detecting means 4 will be described below with reference to FIGS.
Explanation will be made using 0.

FIGS. 8A and 8B show the smoothing means 5,
It is a figure which shows an example of the characteristic of the smoothing filter used in 6 and 7. The setting of the vertical and horizontal axes is the same as in FIG. Filter characteristic 1 of filter A shown in FIG.
Is a filter characteristic used in the bright part of the image adjacent to the dark part of the image detected by the image detecting means 4. This filter characteristic is basically the same as that of the conventional smoothing filter shown in FIG. 30. The luminance of the image data in the bright portion decreases, and the luminance of the pixel data adjacent to the bright portion increases.

The filter characteristic 2 of the filter B shown in FIG. 8B is a filter characteristic used in a portion other than the "bright portion of the image adjacent to the dark portion of the image" detected by the image detecting means 4. . With this filter characteristic, the brightness of the image data in the bright portion may decrease, but the brightness of the pixel data adjacent to the bright portion does not increase.
In other words, the characteristic is that the bright portion can be smoothed, but the pixel data adjacent to the bright portion is not subjected to the smoothing process. For convenience, the filter characteristic of the filter B in the following embodiment is a characteristic in which the smoothing process is not performed even on the bright image data, that is,
It has the same characteristics as passing image data without smoothing.

The above filter A is applied to the first filter means 32 in the smoothing means 5 in FIG. 6, and the filter B is applied to the filter means 32, for example. Then, the filter A and the filter B are selected by the selection means 3 by the control signal CR1.
Switch with 1.

For example, in the case of each image data before the smoothing processing shown in FIGS. 7A and 7B, ST2 (R2e, G2
e, B2e) and ST8 (R8e, G8e, B8e), to which the filter A of the filter characteristic 1 shown in FIG. 8A is applied. FIG. 8 for other image data
The filter B having the filter characteristic 2 shown in FIG. Therefore, ST2 (R2e, G2e, B2e) and S2
The smoothing process of the filter A is performed on the image data of T8 (R8e, G8e, B8e), and the smoothing process is not performed on the other image data.

FIG. 9 is a diagram for explaining an example of control of the smoothing means 5, 6, 7 by the image detecting means 4. The setting of the vertical and horizontal axes is the same as in FIG. X and y in FIG.
Indicates the control element values of the smoothing filters 5 to 7 by the control signals CR1, CG1, and CB1, and the control element values x,
When both y are 0, smoothing is not performed. When the control element values x and y increase, the degree of smoothing of the image data increases.

More specifically, when the image detecting means 4 detects "a bright part of an image adjacent to a dark part of the image", an arbitrary value which satisfies the following equation (1) is output, thereby performing smoothing. Means 5, 6, 7 smooth the image data.

Expressions for determining the control elements of the bright part of the image adjacent to the dark part of the image 0 <x <1, 0 <y <1, where x = y and x + y <1 Other than the above-mentioned detection locations x = y = 0.・ (1)

FIG. 10 shows that each image data before the smoothing process shown in FIGS. 7A and 7B is selectively smoothed by the image detecting means 4 using the filters A and B shown in FIG. It is a figure showing a result.

The smoothing means 5, 6, and 7 correspond to the image detecting means 4.
7 by the control signals CR1, CG1, and CB1 from FIG.
From the digital image data of the three primary colors shown in (a) and (b), ST2 (R2f, G2f, B2f) and ST8 (R8
f, G8f, B8f) only the image data is smoothed by the filter A, and the other image data is not smoothed by the filter B.

More specifically, ST in FIGS. 10A and 10B
2 (R2f, G2f, B2f) and ST8 (R8f, G8
f, B8f) image data only (R2g, G2
g, B2g) and the decreasing components (R8g, G8g, B8g), but the bright parts ST1 (R1g, G1g, B1g) and ST9 (R9g, G9g, B9g) which are the bright parts adjacent to the image data of ST2 and ST8. ), The brightness does not decrease. Conversely, ST3 (R3g, G3) which is a dark portion adjacent to the image data of ST2 and ST8.
g, B3g) and ST7 (R7g, G7g, B7g) image data, the increasing components (R3g, G3g, B3g)
g) and the increase components (R7g, G7g, B7g) do not increase in luminance.

Next, the operation of the image display device 81 of FIG. 1 will be described. The operation of the image display device 4 will be described in particular with reference to FIGS.
When the three primary colors of red (first color) image data SR1 are input to the image display device 81, the A / D converter 1 samples at a predetermined frequency corresponding to the data format of the input image data SR1. , Into digital image data SR2. Similarly, the A / D converter 2 converts the three primary colors green (second
A / D converter 3 samples the image data SG1 of the three primary colors and converts the image data SB1 into digital image data SB2. Convert.

The image data (SR2, SG2, SB2) converted by the A / D converters 1 to 3 are input to the image detector 4 together with the smoothers 5, 6, and 7, respectively.

FIG. 1 is a flowchart showing the operation of the image detecting means 4 of FIG.
1 will be described. In this case, FIGS. 1, 5 and 6 are referred to.

The image detecting means 4 detects the presence or absence of image data from the input image data of three primary colors (SR2, SG2, SB2) (step S1), and if there is image data (step S1: YES), , Comparing means (21, 2
3, 25), the threshold value storage means (22, 24, 2)
It is determined whether or not the input image data is a dark part of the image by comparing whether or not each input image data is smaller than a threshold value set in advance in (6) (step S2).
If there is no image data (step S1: NO), the process proceeds to step S6.

For example, if the input image data SR2 is a dark part of the image (step S2: YES), the control means CR1 of the image detecting means 4 does not smooth the selecting means 31 in the smoothing means 5 in the second mode. Switching to the filter means (filter B) side (step S3), the image data SR3 as the processing result of the filter B is output from the smoothing means 5 to the display means 8. Other input image data SG2, SB
In the case of No. 2, the selection means in the smoothing means 6 and 7 is switched by the control signals CG1 and CB1, and the filtered image data SG3 and SB3 are output. Hereinafter, the description of the input image data SR2, SG2, and SB2 overlaps, so only SR2 will be described as a representative.

When the level value of the input image data SR2 is larger than the preset threshold value and is not a dark part of the image (that is, it is a bright part) (step S2: NO), the image before and after the input image data SR2 By examining the data, it is determined whether or not it is a "bright portion adjacent to a dark portion" (step S4). If the input image data SR2 is “a bright part adjacent to a dark part” (step S4: YES), the image detecting unit 4 selects the filter A as the first filter unit in the smoothing unit 5. Control signal CR
1 is sent. The selection means 31 in the smoothing means 5 is switched to the first filter means (filter A) by the control signal CR1 (step S5). Then, image data SR3 as a processing result of the filter A is output from the smoothing means 5 to the display means 8.

On the other hand, if the input image data SR2 is not “a bright part adjacent to a dark part” (step S4: NO),
The processing of step S3 is performed, and the control signal CR1 is sent from the image detecting means 4 to select the filter B as the second filter means in the smoothing means 5, and the control signal C
The selection means 31 in the smoothing means 5 is switched to the second filter means (filter B) by R1. Then, image data SR3 as a processing result of the filter B is output from the smoothing unit 5 to the display unit 8.

Thereafter, it is determined whether or not the image data has ended (step S6). If the image data has ended (step S6: YES), the process ends, and if the image data has not ended (step S6: step S6). (NO), the process returns to step S1 again, and image data is detected.

In the present embodiment, since the operation is performed as described above, the smoothing process can be performed only on the image data of the "bright portion adjacent to the dark portion".

Here, the image display device 82 shown in FIG.
The operation different from that of the image display device 81 will be described.

The luminance signal SY1 is input to the A / D converter 9 and the chrominance signal SC1 is input to the A / D converter 10. The A / D converters 9 and 10 sample the input luminance signal SY1 and chrominance signal SC1 at predetermined frequencies and convert them into digital luminance signal SY2 and color signal SY2, respectively. The luminance signal SY2 and the chrominance signal SY2 converted by the A / D conversion means 9 and 10 are input to the matrix means 11, and the image data SR2, SG2, and SB2 of three primary colors are provided.
Is converted to The image data SR2, SG2, and SB2 of the three primary colors converted by the matrix unit 11 are input to the image detection unit 4 and the smoothing units 5, 6, and 7, respectively. Subsequent operations are the same as the operations of the image display device 81 in FIG.

Next, the operation of the image display device 83 shown in FIG. 3 different from that of the image display device 81 shown in FIG. 1 will be described.

The composite signal SP1 is input to the A / D conversion means 12, and the A / D conversion means 12 samples the input composite signal SP1 at a predetermined frequency and converts it into a digital composite signal SP2. A
Composite signal SP2 converted by A / D conversion means 12
Is input to the Y / C separation means 13 and separated into a luminance signal SY2 and a chrominance signal SC2. The luminance signal SY2 and the chrominance signal SC2 separated by the Y / C separation means 13 are input to the matrix means 11, and the three primary color image data SR2, SG
2. Converted to SB2. The subsequent operation is the same as that of the image display device 82 in FIG.

Next, the operation of the image display device 84 of FIG. 4 different from that of the image display device 81 of FIG. 1 will be described.

The red image data SR2 of the digital signal forming the three primary colors is input to the input terminal 15 as the first color digital image data, and the green image data SG2 is input to the input terminal 16 as the second color digital image data. Is entered into
Blue image data SB as the third color digital image data
2 is input to the input terminal 17. The inputted image data SR2 is inputted to the image detecting means 4 and the smoothing means 5, the image data SG2 is inputted to the image detecting means 4 and the smoothing means 6, and the image data SB2 is inputted to the image detecting means 4 and the smoothing means. Input to the conversion means 7. The subsequent operation is the same as that of the image display device 81 in FIG.

In the above description of the operation, the three primary color image data SR2,
When all of SG2 and SB2 are smaller than the threshold values set in advance in the threshold value storage means 22, 24, and 26, the image data is determined as a dark portion of an image displayed on the display means 8; Alternatively, the determination may be made only for the minimum value among the input three primary color image data SR2, SG2, and SB2, and if the image data is smaller than the threshold value, the image may be determined to be a dark portion.

As described above, the image display apparatus according to the first embodiment can reduce the brightness of the adjacent bright portion without increasing the brightness of the dark portion of the image. It is possible to improve the phenomenon that the line looks thin when displayed.

Embodiment 2 In the first embodiment, the image detecting means 4 outputs the image data SR2, SG2,
Although the case where the “bright portion adjacent to the dark portion of the image” is detected from SB2 has been described, the present invention is not limited to this. For example, as in the second embodiment described below, a luminance signal May be configured to detect a bright part of an image adjacent to a dark part of the image from the data of (i).

FIG. 12 is a diagram showing an image display device according to the second embodiment of the present invention. Image display device 8 in FIG.
5 is different from the image display device 81 of the first embodiment in that
A luminance signal calculating unit 15 for calculating and outputting a digital luminance signal SY2 based on the image data SR2, SG2, and SB2 is added, and the image detecting unit according to the first embodiment shown in FIGS. 4 is that the image detecting means 4 which has determined the dark part of the image from the digital image data SR2, SG2 and SB2 of the three primary colors has been changed to an image detecting means 14 which determines the dark part of the image from the luminance signal SY2. is there.

The luminance signal calculating means 15 is, for example, the matrix means 1 in the image display devices 82 and 83 shown in FIGS.
1 performs the processing in the reverse direction of the processing performed by the A / D conversion means 1 to 3
An operation is performed based on R2, SG2, and SB2 to calculate a luminance signal SY2 of the digital signal. The internal configuration of the image detecting means 14 will be described later with reference to FIG.

FIGS. 13 and 14 are block diagrams showing an image display device having another configuration according to the second embodiment of the present invention. The image display device 86 in FIG. 13 differs from the image display device 85 in FIG. 12 in that the image display device 85 in FIG. 12 performs a calculation based on the image data SR2, SG2, and SB2, and outputs a luminance signal SY2 of a digital signal. In order to calculate the luminance signal calculation means 15, the image display device 86 has the same original image data as the analog luminance signal SY1 like the image display device 82 in FIG.
The configuration is such that the brightness signal SY2 of the digital signal output from the A / D conversion means 9 is input to the image detection means 14, and the brightness signal calculation means 15 is not required. Therefore, the configuration of the image detecting means 14 is exactly the same as that of the image display device 85. The other configuration is the same as that of the image display device 85 in FIG.

The difference between the image display device 87 of FIG. 14 and the image display device 86 of FIG. 13 is that the image display device 87 of FIG.
6, the luminance signal SY2 of the digital signal was output from the A / D conversion means 9. However, in the image display device 87, as in the image display device 83 of FIG. Since the composite signal SP1 is combined, a Y / C separation unit 13 for separating the luminance signal SY2 from the digitally converted composite signal SP2 is added. Therefore, the configuration of the image detecting means 14 is exactly the same as that of the image display device 85.
Other configurations are the same as those of the image display device 86 in FIG.

FIG. 15 is a diagram showing the internal configuration of the image detecting means 14 shown in FIGS. The image detection means 14
A comparator 41 corresponding to a luminance signal of a digital signal, for example, a comparator 41 and a threshold storage unit 42 such as a memory, and control signals CR1, CG1, and CB1 are generated from a comparison result of the comparator 41, for example. The control signal generating means 47 includes a microprocessor or the like. The control signals CR1, CG1, CB
1 is image data SR2, SG2, S for each of the three primary colors
This is a control signal for selecting a filter for performing a smoothing process on B2.

Next, the operation of the image display device of the present embodiment will be described. The difference between the operation of the image display device of the first embodiment and the operation of the image display device of the present embodiment is only the difference between the operation of the image detection means 4 of the first embodiment and the image detection means 14 of the second embodiment. The image detection device 1
Only the operation of No. 4 will be described, and the description of the other operations will be omitted.

In the image detecting device 14 shown in FIG. 15, the luminance signal SY 2 is input to one input section of the comparing means 41. The threshold value storage means 42 is connected to the other input section of the comparison means 41, and a threshold value corresponding to the luminance signal SY2 is input. In the comparing means 41, the luminance signal SY
2 is compared with the stored contents of the threshold value storage means 42, and the comparison result is input to the control signal generation means 47. The control signal generation unit 47 determines from the comparison result of the comparison unit 41 based on a preset value, a value obtained by performing an arithmetic operation, or the like, and selects a smoothing process (filter) from the control signal generation unit 47. Control signals CR1, CG
1 and CB1 are sent to the corresponding smoothing means 5 to 7, respectively.

If the luminance signal SY2 is smaller than a preset threshold value, it is determined that the image data SR2, SG2, SB2 corresponding to the luminance signal SY2 is a dark portion in the display image, and conversely, the luminance signal SY2 is determined. When SY2 is larger than the threshold value, the image data SR2, SG2, and SB2 corresponding to the luminance signal SY2 are determined to be a bright portion in the display image. Then, the image detecting unit 14 detects a bright portion of the image adjacent to the dark portion of the image from the image data of the dark portion and the bright portion of the image determined as described above, as in the first embodiment. Other operations are the same as those in the first embodiment.

As described above, in the image display apparatus according to the second embodiment, the image detecting means is configured to detect the bright portion of the image adjacent to the dark portion of the image from the luminance signal data in the image data. Even in this case, it is possible to reduce the brightness of the adjacent bright parts without increasing the brightness of the dark parts of the image. Can be.

Embodiment 3 Embodiments 1 and 2 above
In the above, the case where the image detecting means 4 or the image detecting means 14 detects a bright portion of an image adjacent to a dark portion of the image has been described. However, the present invention is not limited to this. As shown in FIG. 3, a configuration may be adopted in which a bright portion of an image adjacent to the outline of the image is detected.

FIG. 16 is a diagram showing an image detecting means in the image display device according to the third embodiment of the present invention. In addition,
The image detecting means according to the third embodiment includes an image detecting means 4 in any image display apparatus according to the first embodiment shown in FIGS.
Can be used in place of

The main difference between the image detecting means 24 of the third embodiment and the image detecting means 4 of the first embodiment shown in FIG. 5 is that each of the input image data SR2, SG2 and SB2 is one. Primary differentiating means 43, 48, 53 for performing secondary differential processing
And comparing means 44, 49, 54 for comparing the outputs of the primary differentiating means 43, 48, 53 with a predetermined threshold value, and a threshold value for comparison by the comparing means 44, 49, 54. This is the point that threshold storage means 45, 50, and 55 are added. Accordingly, the control signal generating means 56 can not only detect the bright part of the image adjacent to the dark part of the image as in the first or second embodiment, but also output the contour of the image by the output of the comparing means 44, 49, 54. Is also detectable.

The comparing means 41, 46, 51 and the threshold value storing means 42, 4 in the image detecting means 24 of FIG.
7 and 52 are the same as those in the first embodiment shown in FIG.
Respectively correspond to the configurations of the comparison means 21, 23, 25 and the threshold value storage means 22, 24, 26 in the image detection means 4.

Next, the operation of the image detecting means 24 for detecting a bright portion of an image adjacent to the outline of the image will be described.

FIG. 17 is a flowchart showing the operation of the image detecting means 24 of FIG. Step S1 in FIG.
Steps S1 to S13 are the same as steps S1 to S3 of the first embodiment shown in FIG. 11, respectively, and steps S15 to S1 in FIG.
Steps 6 to 6 are the same as steps S5 to S6 of the first embodiment shown in FIG. Therefore, only step S14 of the third embodiment, which is replaced by step S4 of the first embodiment, will be described.

In step S14, since the image data is found to be a bright portion from the determination result in step S13, it is determined whether or not the image data is a contour portion.
When the image data is a contour (step S14: YE
In S), the process proceeds to step S15 to select the filter A, and if the image data is not a contour portion (step S14:
(NO), the process proceeds to step S13 to select the filter B.

Here, the method of determining whether or not the image data is an outline in the image detecting means 24 will be described in more detail.

The primary differentiating means 43, 4 of the image detecting means 24
8 and 53, the input image data SR2 of the three primary colors,
SG2 and SB2 are first-order differentiated with arbitrary characteristics. The first-order differentiation results of the first-order differentiating means 43, 48, and 53 are compared with the comparing means 4
In 4, 49 and 54, threshold storage means 45, 5
It is compared with each threshold value preset and stored at 0 and 55. If the primary differentiation results of the primary differentiating means 43, 48, 53 are larger than the respective thresholds, the comparing means 44, 4
Based on the outputs from 9 and 54, the control signal generating means 56 determines that the image data SR2, SG2 and SB2 are the contours of the image.

On the other hand, the image data SR2, SG2, SB2
Are compared in the comparing means 41, 46, 51 with the respective threshold values preset and stored in the threshold value storing means 42, 47, 52. This comparison result indicates that the image data SR2, SG2, S
When B2 is larger than each threshold value, the comparing means 41,
Based on the outputs from 46 and 51, the control signal generating means 56 determines that the image data SR2, SG2 and SB2 are bright portions of the image.

Then, the control signal generating means 56 further detects a bright portion adjacent to the outline of the image based on the determination result of the outline of the image and the determination result of the bright portion of the image,
As shown in FIG. 9 of the first embodiment, control signals CR1 and CR1 including control elements x and y are applied to image data SR2, SG2 and SB2 corresponding to bright portions of an image adjacent to the outline of the detected image. CG1, CB1 are generated and smoothing means 5,
Output to 6 and 7. Subsequent operations are the same as in the first embodiment, and a description thereof will not be repeated.

Here, in the above description of the operation of the present embodiment, in the bright part of the image adjacent to the contour of the image detected by the image detecting means 24, the control elements x, Control signals CR1 and CG having arbitrary values as y
1, the case where CB1 is generated and output has been described. However, the control elements x, y are determined based on the differentiation results of the primary differentiating means 43, 48, 53, and the control signals CR1, CG1,
CB1 can be generated. Hereinafter, a method of determining the control elements x and y will be described.

In the image detecting means 24, the following (2)
First-order differentiation is performed for each color based on the two transfer functions shown in the equations.

H1 (z) = 1−z ^{+ 1} , where H1 (z) ≧ 0 H2 (z) = 1−z− ¹ , where H2 (z) ≧ 0 (2)

Next, a larger differential result is selected from the two differential results of the above-described equation (2) for each color, and an arbitrary coefficient j, k is added to the average value of the three values for each selected color. To determine x and y.

For example, the differentiation result of each color is represented by red (rh
1, rh2), green (gh1, gh2), blue (bh1, b
h2), x and y can be expressed by the following equation (3).

Dr = max (rh, rh2) dg = max (gh1, gh2) db = max (bh1, bh2) x = j × (dr + dg + db) / 3 y = k × (dr + dg + db) / 3: max (a, b) shows the selection of the larger of a and b. ... (3)

In the above equation (3), the smoothing means 5,
Although the method of calculating the control elements x and y in the control signals CR1, CG1, and CB1 of 6, 7 has been described, the control elements x, y
The method of calculating y is not limited to this. For example, a calculation method of selecting a maximum value or a minimum value from the differentiation result of each color and multiplying the selected value by an arbitrary coefficient may be used.

In the above description of the operation, the outline of the image is determined from a preset threshold value, and the bright portion of the image is determined from another preset threshold value. Although the method for detecting the bright portion of the image adjacent to the contour has been described, the detection method is not limited to the above. For example, the primary differential result indicates that the value is high when the brightness of the bright portion adjacent to the contour is high. Since the value becomes large and the value becomes small when the luminance is low, the bright portion of the image adjacent to the contour of the image is detected using only the above-described first derivative result, and the threshold is set as described above to set the image. The control signals for the smoothing means 5, 6, and 7 may be generated without determining the outline and the bright part of.

In the above description of the operation, the image detecting means 24 determines that the image data SR2, SG2, SB2
From the control signals CR1, CG1, C for the smoothing means 5 to 7
The method of determining the control elements x and y in B1 has been described. For example, the control elements x and y in the control signals CR1, CG1, and CB1 are converted from the luminance signal SY2 as in the second embodiment.
In the case where the above is applied to the image detecting means 14 for determining the image signal, the configuration may be such that only the primary differential result of the luminance signal SY2 is used.

In the third embodiment, the image data S
The result of the first-order differentiation of R2, SG2, SB2 or the luminance signal SY2 has been described using the transfer function of the above equation (2), but the present invention is not limited to this, and the first-order differentiation is not limited to this. The results obtained can be used.

In the third embodiment, since the operation is performed as described above, the smoothing process can be performed only on the image data of “the bright part of the image adjacent to the outline of the image”.

Embodiment 4 In Embodiments 1 and 2 described above, the image detecting unit 4 and the image detecting unit 14
Determine the dark part of the image based on a preset threshold,
A case has been described in which a bright part of an image adjacent to a dark part of an image is detected. However, the present invention is not limited to this. For example, as in the fourth embodiment described below, a dark part of an image having an arbitrary width or less is used. May be configured so as to detect a bright portion of an image adjacent to.

FIG. 18 is a diagram showing an image detecting means in the image display device according to the fourth embodiment of the present invention. In addition,
The image detecting means according to the fourth embodiment corresponds to the image detecting means 4 in the arbitrary image display device according to the first embodiment shown in FIGS.
Can be used in place of

The main difference between the image detecting means 34 of the fourth embodiment and the image detecting means 24 of the third embodiment shown in FIG. 16 is that the image detecting means 24 of FIG. , SG2, and SB2 perform first-order differentiating processing, but the first-order differentiating means 43, 48, and 53 are replaced by two differentiating means for each input image data SR2, SG2, and SB2.
The point is that it has been changed to secondary differentiating means 63, 68, 73 for performing the secondary differentiating process. Accordingly, the control signal generating means 86 can not only detect the bright part of the image adjacent to the dark part of the image as in the first or second embodiment, but also output an arbitrary width by the output of the comparing means 44, 49, 54. Another difference is that the following image is changed so that an image adjacent to a dark portion can be detected.

Further, the configurations of the comparing means 61, 64, 66, 69, 71, 74 and the threshold value storing means 62, 65, 67, 70, 72, 75 in the image detecting means 34 of FIG. 16, comparing means 41, 44, 46, 49, 51, 5 in the image detecting means 24 of the third embodiment shown in FIG.
4 and threshold storage means 42, 45, 47, 50, 5
2, 55 respectively.

FIGS. 19 (a) and (b) show FIGS.
FIG. 9 is a diagram illustrating a result of smoothing the image data before smoothing processing illustrated in (b) by the image display device of the present embodiment. Figure 1
FIG. 9A is a diagram illustrating a luminance distribution of each cell when a white line image is displayed on a black background using the display unit of the image display device according to the fourth embodiment, and FIG. 13B is a diagram illustrating a luminance distribution of each cell when a black line image is displayed on a white background using the display unit of the image display device according to the fourth embodiment. The settings of the horizontal axis and vertical axis in FIGS. 19A and 19B are the same as those in FIG.

In FIG. 19A, ST0 (R0m, G0m, B0m) to ST0 are detected by the image detecting means 34 of FIG.
1 (R1m, G1m, B1m) and ST3 (R3m, G1m
3m, B3m)-ST4 (R4m, G4m, B4m)
Is not determined as a dark part of an image having an arbitrary width or less, the smoothing means 5, 6, and 7 do not perform the smoothing process on the image data of ST0 to ST4.

In FIG. 19B, ST7 (R7m, G7m, B7m) is determined by the image detecting means 34 of FIG. 18 as a dark portion of an image having an arbitrary width or less.
(R6m, G6m, B6m) and ST8 (R8m, G8
m, B8m) is detected as a bright part of an image adjacent to a dark part of an image having an arbitrary width or less. As a result, the smoothing means 5,
ST6 (R6m, G6m, B6m) and ST8
The smoothing process is performed only on the image data corresponding to the portion (R8m, G8m, B8m). Therefore, ST1
(R1m, G1m, B1m), ST2 (R2m, G2
m, B2m), ST3 (R3m, G3m, B3m), S
For T7 (R7m, G7m, B7m), the smoothing process is not performed, and the increasing components ST1 (R1n, G1n, B
1n), ST3 (R3n, G3n, B3n), ST7
(R7n, G7n, B7n) and decreasing ST2 (R2
n, G2n, B2n) do not appear in the outputs of the smoothing means 5, 6, 7.

Next, the operation of the image detecting means 34 for detecting a bright portion of an image adjacent to a dark portion of an image having an arbitrary width or less will be described.

FIG. 20 is a flowchart showing the operation of the image detecting means 34 of FIG. Step S2 in FIG.
Steps S1 to S23 are the same as steps S1 to S3 of the first embodiment shown in FIG. 11, respectively, and steps S25 to S2 in FIG.
Steps 6 to 6 are the same as steps S5 to S6 of the first embodiment shown in FIG. Therefore, only step S24 of the fourth embodiment, which is replaced by step S4 of the first embodiment, will be described.

In step S24, since the image data is found to be a bright portion from the determination result in step S23, it is determined whether or not the image data is an image adjacent to a dark portion of an image having an arbitrary width or less. . If the image data is an image adjacent to a dark part of an image having an arbitrary width or less (step S24: YES), the process proceeds to step S25, where a filter A is selected, and a filter A is selected. When the images are not adjacent images (step S24: NO)
, The process proceeds to step S23 to select the filter B.

Here, the method of determining whether or not the image data in the image detecting means 34 is a bright portion of an image adjacent to a dark portion of an image having an arbitrary width or less will be described in more detail.

The secondary differentiating means 63 and 6 of the image detecting means 34
8 and 73, the input three primary color image data SR2,
SG2 and SB2 are secondarily differentiated with arbitrary characteristics. The secondary differential results of the secondary differential means 63, 68, and 73 are compared with the comparison means 6
In 4, 69 and 74, threshold value storage means 65 and 7
It is compared with each threshold value preset and stored at 0 and 75. If the secondary differentiation results of the secondary differentiation means 63, 68, 73 are larger than the respective threshold values, the comparison means 64, 6
Based on the outputs from 9 and 74, the control signal generating means 76 determines that the image data SR2, SG2 and SB2 are images adjacent to the dark portion of the image having an arbitrary width or less.

On the other hand, image data SR2, SG2, SB2
Are compared in the comparing means 61, 66, 71 with the respective threshold values preset and stored in the threshold value storing means 62, 67, 72. This comparison result indicates that the image data SR2, SG2, S
If B2 is larger than each threshold value, the comparing means 61,
Based on the outputs from 66 and 71, the control signal generating means 76 determines that the image data SR2, SG2 and SB2 are bright portions of the image.

Then, the control signal generating means 76 further determines whether the image having an arbitrary width or less is smaller than the arbitrary width based on the determination result of the image adjacent to the dark portion of the image having the arbitrary width or less and the determination result of the bright portion of the image. A first embodiment is described in which a bright portion of an image adjacent to a dark portion is detected, and image data SR2, SG2, and SB2 corresponding to a bright portion of an image adjacent to the dark portion of an image having an arbitrary width or less are detected. Control elements x, y as shown in FIG.
Are generated and output to the smoothing means 5, 6, 7. Subsequent operations are the same as in the first embodiment, and a description thereof will not be repeated.

More specifically, for example, by determining the filter characteristics of each color so that the result of the smoothing process of FIG. It is possible to improve the phenomenon that the line looks thin, and to reduce the decrease in sharpness in the outline portion.

R6> G6> B6 R8 <G8 <B8 (4)

Here, in the above description of the operation of the fourth embodiment, in the bright part of the image adjacent to the dark part of the image having an arbitrary width or less detected by the image detecting means 34, the smoothing means 5, 6,. The case has been described in which the control signals CR1, CG1, and CB1 having arbitrary values are generated and output as the control elements x and y of the seventh control element. , Y to determine the control signal CR
1, CG1 and CB1 can be generated. Hereinafter, a method of determining the control elements x and y will be described.

More specifically, the image detecting means 34 performs a second differentiation for each color based on the two transfer functions shown in the following equation (5).

H3 (z) = (1 + z− ² ) / 2−z− ¹ , where H3 (z) ≧ 0 H4 (z) = (1 + z ^{+ 2} ) / 2−z ^{+ 1} , where H4 (z) ≧ 0 ... (5)

Next, a larger differential result is selected from the two differential results obtained by the above equation (5) for each color, and an arbitrary coefficient j, k is added to the average value of the three values for each selected color. To determine x and y.

For example, the differentiation result of each color is represented by red (rh
3, rh4), green (gh3, gh4), blue (bh3, b
Assuming that h4), x and y can be expressed by the following equation (6).

Dr = max (rh3, rh4) dg = max (gh3, gh4) db = max (bh3, bh4) x = j × (dr + dg + db) / 3 y = k × (dr + dg + db) / 3max (a, b) ) Indicates the larger of a and b. ... (6)

In the above equation (6), the smoothing means 5,
Although the method of calculating the control elements x and y in the control signals CR1, CG1, and CB1 of 6, 7 has been described, the control elements x, y
The method of calculating y is not limited to this. For example, a calculation method of selecting a maximum value or a minimum value from the differentiation result of each color and multiplying the selected value by an arbitrary coefficient may be used.

In the above description of the operation, a dark portion of an image having an arbitrary width or less is determined from a preset threshold value, and a bright portion of the image is determined from another preset threshold value. Although the method for detecting a bright portion of an image adjacent to a dark portion of an image having an arbitrary width or less has been described, the detection method is not limited to the above. Is smaller, and the value increases as the brightness of the bright portion of the adjacent image increases, so that the bright portion of the image adjacent to the contour of the image is detected using only the above-described second differentiation result. As described above, the control signal for the smoothing means 5, 6, and 7 may be generated without setting the threshold value and determining the dark portion and the bright portion of the image having an arbitrary width or less.

In the above description of the operation, the image detecting means 24 determines that the image data SR2, SG2, SB2
From the control signals CR1, CG1, C for the smoothing means 5 to 7
The method of determining the control elements x and y in B1 has been described. For example, the control elements x and y in the control signals CR1, CG1, and CB1 are converted from the luminance signal SY2 as in the second embodiment.
In the case where the above is applied to the image detecting means 14 for determining the image signal, the configuration may be such that only the secondary differential result of the luminance signal SY2 is used.

In the fourth embodiment, the image data S
Although the result of the second derivative of R2, SG2, SB2 or the luminance signal SY2 has been described using the transfer function of the above equation (5), the present invention is not limited to this. The results obtained can be used.

In the fourth embodiment, since the operation is performed as described above, it is possible to perform the smoothing process only on the image data of the “bright portion of the image adjacent to the dark portion of the image having an arbitrary width or less”. it can.

As described above, the image display device according to the fourth embodiment can reduce the brightness of the adjacent bright portion without increasing the brightness of the dark portion of the image, and can display dark characters and lines on a bright background. In this case, it is possible to improve the phenomenon that the line looks thin.

In the above description, the method of detecting a bright portion of an image adjacent to a dark portion of an image having an arbitrary width or less is 2
Although the case where the next derivative is used has been described, the present invention is not limited to this. For example, similar to the first embodiment, a bright portion of an image and a dark portion of the image are determined based on a threshold,
By measuring the width of the dark part of the determined image, it is identified that the dark part of the image is smaller than an arbitrary width, and the light part of the image adjacent to the dark part of the image smaller than the identified arbitrary width is detected. You may do it.

Further, for example, by comparing the dark portion of the image determined based on the threshold value with a plurality of binary patterns, it is determined that the dark portion of the image is smaller than an arbitrary width. Alternatively, a bright portion of an image adjacent to a dark portion of an image having an arbitrary width or less may be detected.

Embodiment 5 FIG. Embodiments 1 to 4 described above
Then, the smoothing means 5, 6, and 7 use the filters having the filter characteristics shown in FIGS. 8A and 8B to “the bright portion of the image adjacent to the dark portion of the image” and the “adjacent to the outline of the image”. Although the case where the "bright portion of the image to be performed" or the "bright portion of the image adjacent to the dark portion of the image having an arbitrary width or less" is smoothed has been described, the present invention is not limited thereto. As in the fifth embodiment, smoothing can be performed using a filter having different characteristics for each of the three primary colors.

FIG. 21 is a diagram showing an example of the characteristics of the smoothing filter having different characteristics for each of the three primary colors used in the smoothing means 5, 6, and 7. More specifically, the filter characteristic FG3 used for the green (second color) smoothing means 6 shown in FIG. 21 (filter C) is the same as the filter characteristic 1 shown in FIG. It has the same characteristics as FG1.

The filter characteristic FR used for the red (first color) smoothing means 5 shown in FIG. 21 (filter C).
For 1, any value that satisfies the following equation (7) may be used.

0 <x <1, 0 ≦ y <1, where x> y and x + y <1 (7)

The filter characteristic FB used for the blue (third color) smoothing means 7 shown in FIG. 21 (filter C).
3 may be any value that satisfies the following equation (8).

0 ≦ x <1, 0 <y <1, where x <y and x + y <1 (8)

FIG. 22 shows that the image detecting means 4 selectively smoothes each image data before the smoothing processing shown in FIGS. 7A and 7B using the filter C shown in FIG. 21 and the filter B shown in FIG. It is a figure showing the result of having performed processing.

The smoothing means 5, 6, 7 is provided with the image detecting means 4
7 by the control signals CR1, CG1, and CB1 from FIG.
From the digital image data of the three primary colors shown in (a) and (b), ST2 (R2f, G2f, B2f) and ST8 (R8
f, G8f, B8f) only the image data is smoothed by the filter C, and the other image data is not smoothed by the filter B.

Specifically, the ST shown in FIGS.
2 (R2j, G2j, B2j) and ST8 (R8j, G8
j, B8j), only the phase of each color is different in the filter characteristic of FIG.
2k, B2k) and the decrease components (R8k, G8k), but the bright parts ST1 (R1j, G1j, B1j) and ST9 adjacent to the image data of ST2 and ST8.
For the image data of (R9j, G9j, B9j),
ST3 (R3j, G3j, B3j), which is a dark portion adjacent to the image data of ST2 and ST8, without a decrease in luminance.
And the image data of ST7 (R7j, G7j, B7j), the increasing component (R3k, G3k) and the increasing component (G7
k, B7k).

FIGS. 23 (a) and 23 (b) correspond to FIGS.
FIG. 9 is a diagram illustrating a result of smoothing the image data before smoothing processing illustrated in (b) by the image display device of the present embodiment. FIG.
FIG. 3A is a diagram illustrating a luminance distribution of each cell when a white line image is displayed on a black background using the display unit of the image display device according to the fifth embodiment, and FIG. 13B is a diagram illustrating a luminance distribution of each cell when a black line image is displayed on a white background using the display unit of the image display device according to the fifth embodiment. The settings of the horizontal axis and vertical axis in FIGS. 23A and 23B are the same as those in FIG.

In FIG. 23A, as in FIG. 19A, the smoothing means 5, 6, 7 do not perform the smoothing processing on the image data of ST0 to ST4.

In FIG. 23B, as in FIG. 19B, the smoothing means 5, 6, and 7 perform the smoothing process on the image data of ST6 and ST8. Since the phase of each color is different in the filter characteristics, G6 in ST6
Only p and B6p and only G8p and R8p in ST8 are smoothed. Therefore, ST1 (R1p, G1p, B
1p), ST2 (R2p, G2p, B2p), ST3
(R3p, G3p, B3p), ST7 (R7p, G7
p, B7p), the smoothing process is not performed, and G1q and B1q in the increasing component ST1, R3 in ST3.
q and G3q, R7q, G7q and B7 in ST7
q or R2q, G2q and B2q in the decreasing component ST2 do not appear in the outputs of the smoothing means 5, 6, 7.

More specifically, filter characteristics for each color are determined so as to satisfy the following equation (9) as a result of smoothing.

R2> G2> B2 B8> G8> R8 (9)

In the above description of the operation, the case where the input image data is digital image data composed of three primary colors has been described. However, the present embodiment is not limited to this, and is constituted by luminance and color. May be applied to digital image data or composite digital image data.

In the fifth embodiment, since the operation is performed as described above, the smoothing process can be performed by using filters having different characteristics for each of the three primary colors, thereby further reducing the reduction in image sharpness. Can be.

Embodiment 6 FIG. In the second embodiment, a case has been described in which a bright portion of an image adjacent to a dark portion of an image is detected from data of a luminance signal in image data. However, the present invention is not limited to this. It may be configured as in the sixth embodiment.

FIG. 24 shows an image display device according to the sixth embodiment of the present invention. Image display device 8 in FIG.
8 is different from the image display device 85 of the second embodiment in that
Since the means for calculating and outputting the digital luminance signal SY2 based on the image data SR2, SG2 and SB2 is replaced by the luminance signal calculating means 15 as the inverse matrix means 91, the color signal SC2 is also output from the inverse matrix means 91. The point that the averaging means 93 is arranged before the matrix means 11 to average the luminance signal SY2 to output the luminance signal SY3, and the arrangement of the averaging means 93 is arranged before the matrix means 11 Due to the change, the output of the image detecting means 92 is a control signal CY1 for selecting a filtering process for the luminance signal SY2. Other configurations are the same as those of the image display device 85 in FIG.

FIG. 25 is a block diagram showing an image display device having another configuration according to the sixth embodiment of the present invention. FIG.
The image display device 89 of the fifth embodiment differs from the image display device 86 of the second embodiment in FIG. 13 in that the averaging means 93 is arranged in front of the matrix means 11 and the luminance signal SY2 Are averaged to output the luminance signal SY3, and the arrangement of the averaging means 93 is changed to a stage preceding the matrix means 11, so that the image detecting means 9 is output.
2 is a control signal CY1 for selecting a filtering process for the luminance signal SY2. Other configurations are the same as those of the image display device 86 in FIG.

FIG. 26 is a diagram showing the internal configuration of the image detecting means 92 shown in FIGS. The image detecting means 92
A comparator 95 corresponding to the luminance signal of the digital signal, for example, a comparator 95, and a threshold storage unit 94, for example, a memory, and a microprocessor that generates the control signal CY1 from the comparison result of the comparator 94, for example, And a control signal generating means 96.
The control signal CY1 is a control signal for selecting a filter for performing a smoothing process on the luminance signal SY2.

FIG. 27 shows the smoothing means 9 of FIGS.
FIG. 3 is a diagram showing an internal configuration of a third embodiment. The smoothing means 93 is, for example, a selection means 97 such as a one-input / two-output switch.
And two filters (first filter means 98 and second filter means 99) connected to the respective outputs of the selection means 97 and having different characteristics.

At the smoothing means 93, the digital luminance signal S
Y2 is input to the selection means 97. At this time, the output of the selecting means 97 is output to the control signal generating means 9 of the image detecting means 92.
The control signal CY1 output from 6 controls one of the two outputs to be selected. The luminance signal SY2 is input to the filter means selected by the selection means 97, and an output processed by the filter characteristics is output to the display means 8 as image data SY3.
It should be noted that, as the filter characteristics in this case, the filter characteristics in the case where the smoothing is not performed can be selected. That is, it is possible to select to output the input image data SY2 or the like as SY3 or the like without performing the smoothing processing (filter processing).

Next, the operation of the image display device of the present embodiment will be described. The difference between the operation of the image display device of the second embodiment and the operation of the image display device of the present embodiment is that the operation of the image detecting means 14 and the averaging means 5 to 7 of the second embodiment is different from the operation of the image display device of the sixth embodiment. Since only the operation differs from the operation of the detection means 92 and the averaging means 93, only the operation of the image detection device 92 and the averaging means 93 will be described below.
Description of other operations is omitted.

In the image detecting device 92 shown in FIG. 26, the luminance signal SY2 is inputted to one input section of the comparing means 95. The threshold value storage means 94 is connected to the other input section of the comparison means 95, and a threshold value corresponding to the luminance signal SY2 is input. In the comparing means 95, the luminance signal SY
2 is compared with the contents stored in the threshold value storage means 94, and the comparison result is input to the control signal generation means 96. The control signal generating means 96 determines from the comparison result of the comparing means 95 based on a preset value or a value obtained by performing an arithmetic processing or the like, and selects a smoothing process (filter) from the control signal generating means 96. Is transmitted to the smoothing means 93.

If the luminance signal SY2 is smaller than the preset threshold value, it is determined that the luminance signal SY2 is a dark portion in the display image. Conversely, if the luminance signal SY2 is larger than the threshold value, , The luminance signal SY2 is determined to be a bright portion in the display image. Then, the image detecting means 9
2 detects a bright portion of the image adjacent to the dark portion of the image from the luminance signals of the dark portion and the bright portion of the image determined as described above, as in the second embodiment. Other operations are the same as the operations of the second embodiment.

As described above, in the image display apparatus according to the sixth embodiment, the image detecting means is configured to detect the bright portion of the image adjacent to the dark portion of the image from the luminance signal data in the image data. Even in this case, it is possible to reduce the brightness of the adjacent bright parts without increasing the brightness of the dark parts of the image, thus improving the phenomenon that lines appear thin when displaying dark characters and lines on a light background. Therefore, the configuration can be simpler than in the second embodiment in which three smoothing means are required to smooth image data of three primary colors.

In each of the embodiments described above, one pixel of the display means 8 has been described in the case where cells of three primary colors are arranged in the order of red (R), green (G), and blue (B) from the left. However, the present invention is not limited to this, and can be applied to an image display device having display means in another arrangement order.

[0169]

As described above, according to the first and eighth aspects of the present invention, a smoothing process can be performed only on a light portion adjacent to a dark portion. It is possible to provide an image display device that does not look thin, does not smooth bright characters and lines in a dark background, and does not deteriorate the sharpness of characters and lines.

According to a second aspect of the present invention, in addition to the effect of the first aspect, when data for each of the three primary colors is obtained from the input image data, the data for each of the three primary colors is individually obtained. In addition, a smoothing process can be selectively performed.

According to a third aspect of the present invention, in addition to the effect of the second aspect, when data and a luminance signal for each of the three primary colors are obtained from the input image data, each of the three primary colors is obtained based on the luminance signal. Can be individually and selectively subjected to a smoothing process.

According to the fourth and ninth aspects of the present invention, a smoothing process can be performed only on a light portion of an image adjacent to an outline of the image, so that dark characters and lines are displayed on a lighter background than in the first aspect. Thus, an image display apparatus can be provided in which lines do not look thin, bright characters and lines in a dark background are not smoothed, and the sharpness of characters and lines does not deteriorate.

According to the fifth and tenth aspects of the present invention, a smoothing process can be performed only on a bright portion of an image adjacent to a dark portion having a predetermined width or less. Can provide an image display apparatus in which lines do not look thin, bright characters and lines in a dark background are not smoothed, and the sharpness of characters and lines does not deteriorate.

According to the sixth and eleventh aspects of the present invention, it is possible to change the characteristics of a filter for performing a smoothing process for each of the three primary colors, so that a decrease in image sharpness can be reduced more than in the first aspect. it can.

According to the seventh and twelfth aspects of the present invention, in addition to the effect of the third aspect, only one smoothing means is not required for smoothing image data of three primary colors. Therefore, the configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating another configuration example of the image display device in FIG. 1;

FIG. 3 is a block diagram showing another configuration example of the image display device of FIG. 1;

FIG. 4 is a block diagram showing another configuration example of the image display device of FIG. 1;

FIG. 5 is a diagram showing an internal configuration of the image detecting means 4 of FIGS. 1 to 4;

FIG. 6 is a diagram showing an internal configuration of the smoothing means 5 of FIGS.

FIGS. 7A and 7B are diagrams illustrating a luminance distribution of each cell when an image of a dark portion and a bright portion is displayed.

FIGS. 8A and 8B are diagrams illustrating an example of characteristics of a smoothing filter used in a smoothing unit.

FIG. 9 is a diagram illustrating an example of control of a smoothing unit by an image detection unit.

FIGS. 10A and 10B are diagrams showing the results of performing smoothing processing using the filter of FIG. 8 on each image data before the smoothing processing of FIGS. 7A and 7B; is there.

FIG. 11 is a flowchart showing the operation of the image detecting means 4 of FIG.

FIG. 12 is a diagram showing an image display device according to a second embodiment of the present invention.

FIG. 13 is a block diagram showing an image display device having another configuration of FIG.

FIG. 14 is a block diagram showing an image display device having another configuration of FIG.

FIG. 15 is a diagram showing an internal configuration of the image detecting means 14 of FIGS. 12 to 14;

FIG. 16 is a diagram showing an image detecting means in the image display device according to the third embodiment of the present invention.

FIG. 17 is a flowchart showing the operation of the image detecting means of FIG.

FIG. 18 is a diagram illustrating an image detecting unit in the image display device according to the fourth embodiment of the present invention.

FIGS. 19A and 19B are diagrams showing the result of smoothing the image data before the smoothing process shown in FIGS. 29A and 29B.

FIG. 20 is a flowchart showing the operation of the image detecting means of FIG.

FIG. 21 is a diagram showing an example of the characteristics of a smoothing filter having different characteristics for each of the three primary colors used in the smoothing means according to the fifth embodiment of the present invention.

FIG. 22 is a diagram showing a result of smoothing each image data before the smoothing processing in FIGS. 7A and 7B.

23 (a) and (b) show FIGS. 29 (a) and (b)
FIG. 7 is a diagram showing a result of smoothing image data before smoothing processing shown in FIG.

FIG. 24 is a diagram illustrating an image display device according to a sixth embodiment of the present invention.

FIG. 25 is a block diagram showing an image display device having another configuration according to the sixth embodiment of the present invention.

FIG. 26 is a diagram showing an internal configuration of the image detecting means 92 of FIGS. 24 and 25;

FIG. 27 is a diagram showing the internal configuration of the smoothing means 93 in FIGS. 24 and 25;

FIG. 28 is a block diagram illustrating a configuration of a conventional image display device.

FIGS. 29A and 29B are diagrams showing a luminance distribution for each cell.

FIG. 30 is a diagram showing characteristics of a smoothing filter used for conventional contour correction.

31 (a) and (b) are luminance distributions of an image obtained by smoothing the image shown in FIG. 29 using the smoothing filter of FIG. 30.

[Explanation of symbols]

1 A / D conversion means, 2 A / D conversion means, 3 A / D
Conversion means, 4 image detection means, 5 smoothing means, 6 smoothing means, 7 smoothing means, 8 display means, 9 A / D conversion means, 10 A / D conversion means, 11 matrix means, 12 A / D conversion means , 13 Y / C separation means, 1
4 image detection means, 15 input terminals, 16 input terminals,
17 Input terminal.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 1/409 H04N 1/40 D 5L096 1/46 101C 9/68 103 1/46 Z F term (reference) 5B057 CA01 CA12 CA16 CB01 CB12 CB16 CE05 DC16 5C066 AA03 BA20 CA05 DA05 DB07 DC01 DD07 EC02 EE03 EE04 EE05 GA01 GA02 GA04 GA05 HA02 JA02 KC01 KD02 KD04 KE04 KE05 KE19 KG01 KM13 KM14 MP15 PP02 PP19 PP02 PP19 SS06 5C079 HB01 LA02 LA06 LA11 LA15 LA31 MA17 NA02 NA06 PA05 5C082 BA02 CA21 CB01 DA51 MM10 5L096 AA02 DA04 EA06 FA06

Claims (12)

[Claims] 1. A smoothing means for selectively performing smoothing processing on input image data, determining a dark portion and a light portion of the image from the input image data, and determining image data of a light portion adjacent to the dark portion. Image detection means for generating a control signal for selecting a smoothing process to be applied to the image data and sending the control signal to the smoothing means; anddisplay means for displaying an image based on the image data output from the smoothing means. Characteristic image display device. 2. When the data for each of the three primary colors is obtained from the input image data, the smoothing means selects the data for each of the three primary colors individually and selectively by the control signal. Wherein the image detecting means generates a control signal individually for the data of each of the three primary colors and sends it to the corresponding smoothing means. The image display device according to claim 1. 3. When a luminance signal is obtained together with data for each of the three primary colors from the input image data, the image detecting means generates a control signal for each of the three primary colors based on the luminance signal. 3. The image display device according to claim 2, wherein the image data is sent to a corresponding smoothing means. 4. The image detecting means can determine a dark portion and a bright portion of an image from input image data and detect a contour portion of the image. When an image adjacent to the contour of the image is a bright portion, 4. The image display device according to claim 1, wherein a control signal for selecting a smoothing process to be applied to the image data of the bright portion is generated and sent to the smoothing means. 5. The image detecting means distinguishes between a dark portion and a bright portion of an image from input image data, and can detect that the dark portion of the image has a predetermined width or less, and the dark portion of the image has a predetermined width or less. 4. The method according to claim 1, wherein a control signal for selecting a smoothing process to be applied to image data of a light portion of an image adjacent to a dark portion of the image is generated and sent to the smoothing means. 2. The image display device according to claim 1. 6. The image display device according to claim 2, wherein the smoothing unit changes a characteristic of a filter that performs a smoothing process for each of the three primary colors. 7. When a luminance signal is obtained together with data for each of the three primary colors from the input image data, the smoothing means selectively performs a smoothing process on the luminance signal by the control signal. The image display device according to claim 1, wherein the image detection unit is provided so as to be able to perform the control, and the image detection unit generates and sends the control signal for the luminance signal. 8. A step of detecting a dark portion of an image from input image data, a step of not performing a smoothing process on the image data when image data serving as a dark portion of the image is detected, Detecting a bright portion of the image from the image data to be processed; selecting a filter for smoothing the image data when image data serving as a bright portion of the image is detected; and terminating the image data. Repeating the above steps until the image is displayed. 9. The step of detecting image data which is a bright portion of the image, further comprising: a filter for smoothing the image data only when the image data is adjacent to a contour portion. 9. The method according to claim 8, wherein the selection is performed.
Image display method described. 10. In the step in which image data serving as a bright part of the image is detected, the image data is further smoothed only when the image data is adjacent to a dark part having a predetermined width. 9. The image display method according to claim 8, wherein a filter is selected. 11. The method according to claim 8, wherein in the step in which image data serving as a bright portion of the image is detected, a filter having different characteristics for each of the three primary colors is selected. The image display method described in the section. 12. The method according to claim 8, wherein in the step of detecting image data serving as a bright portion of the image, a filter for smoothing a luminance signal is selected. Image display method.