JP2000089747A - Method and device for displaying image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for displaying an image capable of improving discrimination property of a character displayed overlapping a background image. SOLUTION: A background image and a discrimination image containing a character overlapped with the background image are acquired (S1, S2). A watched pixel value changed by the total density value of pixels constituting the character incorporated in the vicinity area of respective pixels of the discrimination image is obtained as to the respective pixels of the discrimination image (S3, S4). The density values of respective pixels of the background image corresponding to the respective pixels are adjusted according to the watched pixel values of respective pixels of the discrimination image (S5-S8). Therefore, since the density difference between the background image and the character is increased in the vicinity of the character, the character becomes easy to see. That is, the discrimination property of the character displayed overlapped with the background image is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for displaying an image by superimposing a character on a background image, such as a homepage or a telop, and in particular, to improve the identification or visibility of the character. Regarding technology that can.

[0002]

2. Description of the Related Art For example, on a homepage, characters to be read by an observer are displayed over a background image. In recent years, this background image includes background information in which colors, patterns, and the like are applied, such as photographs. Characters displayed superimposed on a background image with a high density have a small density difference from the background image, and the discriminability may decrease. For example, as shown in FIG. 9A, the characters “A” to “O”, “blue”
Is superimposed on the background image 90, the background image 9
The density difference between 0 and each character is reduced, and the identifiability of each character is reduced. In particular, the character "blue" with a high character pattern density
Kanji like is remarkable. Note that the background image 90 is indicated by diagonal lines for convenience, and that the density of the background decreases as the width of the diagonal lines decreases.

Conventionally, characters are displayed as described below in order to enhance the recognizability of characters superimposed on a background image. For example, as shown in FIG.
For example, the rectangular area 91 including the character displayed on the upper side is painted in white, and the character is displayed on the rectangular area 91, thereby increasing the density difference between the character and the background image, thereby improving the discriminability. . Also, as shown in FIG. 9C, the density in the rectangular area 91 of the background image 90 is reduced uniformly, and characters are displayed on the rectangular area 91, thereby reducing the density difference between the characters and the background image. It is slightly larger to improve the discriminability. Further, as shown in FIG.
By uniformly lowering the overall density and displaying characters on the background image 90, the discriminability is improved.

[0004]

However, the prior art having such a structure has the following problems. For example, in the case shown in FIG. 9B, a part of the background image 90 is completely filled by the rectangular area 91 which is a relatively large area where the character actually overlaps the background image 90. However, there is a problem in that the background information of the background image 90 is completely lost in a region that is relatively wider than the region where the characters actually overlap the background image 90.

In the case shown in FIG. 9C, the density of the area on the background image 90 corresponding to the rectangular area 91 is uniformly reduced, so that the recognizability of characters and the like is slightly improved. In addition, there is a problem that it is difficult to grasp background information in a region relatively wide than a region where characters overlap the background image 90.

Further, in the case shown in FIG. 9D, the entire density of the background image 90 is uniformly reduced.
Although the recognizability of characters and the like is slightly improved, there is a problem that it is difficult to grasp the entire background information of the background image 90.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and improves the discrimination of characters superimposed on a background image and minimizes the loss of background information of the background image. It is an object of the present invention to provide an image display method and an image display apparatus which can perform the method.

[0008]

The present invention has the following configuration in order to achieve the above object. That is, the invention according to claim 1 is an image display method for superimposing a character on a background image and displaying the character on a background image. A process of calculating target pixel information that changes in accordance with the total density information of the pixel group included in the region; and a density difference between the character and the background image increases in accordance with each target pixel information of the identification image. And adjusting the density information of each pixel of the background image corresponding to each pixel of the identification image, and displaying the characters on the background image with the adjusted density information. It is characterized by the following.

According to a second aspect of the present invention, there is provided an image display apparatus for superimposing a character on a background image and displaying the character on the background image. A pixel-of-interest information calculating unit that calculates pixel-of-interest information that changes according to the total density information of the pixel group included in the neighboring area; and, according to each pixel of interest of the identification image,
Background image density adjustment means for adjusting density information of each pixel of the background image corresponding to each pixel of the identification image so that a density difference between the character and the background image is increased, and the density information is adjusted. Display means for displaying the characters superimposed on the background image.

According to a third aspect of the present invention, in the image display device according to the second aspect, the background image density adjusting means includes the character and the character information in each piece of target pixel information calculated by the target pixel information calculating means. An adjusting means for applying an adjustment value for changing the degree of the density difference with the background image,
The density information of each pixel of the background image is adjusted according to each piece of target pixel information on which an adjustment value has been applied by the adjustment unit.

According to a fourth aspect of the present invention, in the image display device according to the second or third aspect, the background image density adjusting means converts each target pixel information calculated by the target pixel information calculating means. The image processing apparatus further includes a threshold value selecting unit that performs selection based on an arbitrary threshold value, and adjusts density information of pixels of the background image corresponding to pixels of the target pixel information selected by the threshold value selecting unit.

[0012]

The operation of the present invention is as follows. According to the invention described in claim 1, for each target pixel of the identification image,
The target pixel information that changes according to the total density information of the pixels included in the neighboring area is obtained. This pixel of interest information has a large value when a nearby pixel forming the character is set as the pixel of interest. The density information of each pixel of the background image corresponding to each pixel of the identification image is adjusted on a pixel-by-pixel basis with each piece of target image information of the identification image. As a result, the pixels of the background image in the vicinity of the pixels constituting the character have a greater density difference with respect to the character than the pixels at other places on the background image. Characters are superimposed and displayed on such a background image.

According to the second aspect of the present invention, the target pixel information calculating means determines, for each target pixel of the identification image, the target pixel information in accordance with the total density information of a pixel group included in a region near each target pixel. The changing target pixel information is calculated. This pixel of interest information has a large value when a nearby pixel forming the character is set as the pixel of interest. The background image density adjusting means adjusts the density information of each pixel of the background image corresponding to each pixel of the identification image on a pixel-by-pixel basis with each piece of target image information of the identification image. As a result, the pixels of the background image in the vicinity of the pixels constituting the character have a greater density difference with respect to the character than the pixels at other places on the background image. The display means superimposes and displays characters on the background image adjusted in pixel units.

According to the third aspect of the present invention, the adjusting means applies the adjustment value to the target pixel information. The background image density adjusting means adjusts the density information of each pixel of the background image according to the target pixel information on which the adjustment value has been applied. It changes according to the adjustment value.

According to the fourth aspect of the present invention, the threshold value selecting means selects target pixel information according to an arbitrary threshold value. The background image density adjusting means adjusts only the density information of each pixel of the background image corresponding to each pixel of the selected target pixel information.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a schematic configuration of an image display device according to an embodiment of the present invention. As shown in FIG. 1, the image display device is configured by a so-called computer in which a CPU 1 for executing various arithmetic processing and the like is connected to a program memory 2 and a work memory 3 via a bus line BL. . The external storage device 4, keyboard 5, mouse 6, printer 7, communication device 8, monitor 9, and the like are connected to the CPU 1 via an input / output interface (not shown) connected to the bus line BL. Note that a computer is a concept including various types of hardware and an operation system that operates the hardware. For example, a computer incorporates a CPU or the like, and each hardware operates independently. In the case where the processing is executed by the computer, the configuration of only the hardware corresponds to the computer.

The CPU 1 operates various kinds of hardware, performs processing according to instructions from various kinds of hardware, and performs predetermined arithmetic processing and the like on page images according to programs stored in the program memory 2. Things. Note that a page image is an image in which identification information having character distinctiveness is superimposed and displayed on a background image including background information such as a color or a pattern of a photograph, for example, a homepage or a telop. It is. Characters include ordinary characters and symbols created with text data, logos created with line drawing data, and the like.

The work memory 3 stores a page image to be processed by the CPU 1, a calculation result, and the like.
The page image is called from the external storage device 4 by the CPU 1 or acquired from the network 10 or the like via the communication device 8.

The external storage device 4 is constituted by, for example, a hard disk device in which page images and the like are stored. Note that the external storage device 4 is not limited to a hard disk, and may be configured by, for example, a CD-ROM drive device, a floppy disk drive device, a magnetic tape recorder device, an IC card reader device, or the like. In the case of such a device, a CD-ROM, a floppy disk, a magnetic tape, an IC card, or the like, which is a storage medium storing a page image or the like, is loaded into the above-described external storage device 4 so that these are stored. A page image or the like is called from the storage medium.

The keyboard 5 and the mouse 6 are used to input parameters for performing predetermined processing to an image, characters to be displayed on the monitor 9 and the like, and to the CPU 1 through a graphical user interface displayed on the monitor 9. Or instructs the process.

The monitor 9 is constituted by a liquid crystal monitor, a CRT, or the like, and displays a page image or a predetermined image in accordance with an instruction from the CPU 1. The image is printed out from the printer 7 as appropriate.

The communication device 8 is constituted by a communication modem or a network card connected to a network 10 such as the Internet, for example. The communication device 8 has a CPU
According to the first instruction, a page image such as a homepage is acquired.

The CPU 1 in this embodiment corresponds to the target pixel information calculating means, background image density adjusting means, adjusting means and threshold value selecting means in the present invention, and the monitor 9 corresponds to the display means.

Hereinafter, the processing performed by the image display device of the present embodiment will be described with reference to the flowchart of FIG.

Step S1 (Acquisition of a page image) When the image display device is started, the CPU 1 reads out the page image stored in the external storage device 4 according to the program stored in the program memory 2, and processes this page image. It is stored in the memory 3. For example, page image 30
Is composed of a background image 31 including background information such as a color and a pattern of a photograph and the like, and an identification character 32 superimposed on the background image 31 as shown in FIG. In this embodiment, for the sake of convenience, as shown in FIG. 3, a background image 31 including background information such as colors and patterns is indicated by oblique lines, and characters superimposed on the background image 31 are represented by, for example, " It is indicated by each identification character 32 represented by “aiueo blue”. In this embodiment, the page image is obtained from the external storage means 4. However, the present invention is not limited to this. For example, a page image such as a homepage established on the Internet via the communication device 8 is obtained. You can also. Note that the identification character 32 is created by text data, and the text data is stored in the work memory 3.

Step S2 (Generation of Identification Image) The CPU 1 raster-expands the text data stored in the work memory 3 and identifies the identification image 3 representing the identification character 32.
3 (see FIG. 4). The identification image 33 is composed of a plurality of pixels 33a, and the density value of the pixels constituting the identification character 32 is represented by “1”, and the density values of the pixels not constituting the identification character 32 are represented by “0”. Is done. CPU1
Stores the generated identification image 33 in the work memory 3. Note that the density value in this embodiment corresponds to the density information in the present invention, and this density information indicates a density value, a so-called luminance value, or the like.

Step S3 (Generate Weight Mask) Based on the font size of the identification character 32, the CPU 1 generates a weight mask of, for example, about twice the font size. For convenience of explanation, a case will be described in which a weighting mask 60 for 5 × 5 elements is generated as shown in FIG.

As shown in FIG. 5, the CPU 1 generates a weighting mask 60 having a size of 5 × 5 elements, for example, with the center element 61 at the center. This weighting mask 60
In, a weighting coefficient for weighting the density value of each pixel included in the area of 5 × 5 pixels of the identification image 33 is set based on, for example, a Gaussian distribution. More specifically, the weighting factor is set so that the weighting factor becomes smaller toward the outside from the central element 61. For example, the weighting factor “1.0” is assigned to the central element 61, and each of the surrounding elements near the central element 61. A weight coefficient “0.5” is set for the element, and a weight coefficient “0.1” is set for each element outside the center element 61.
By the weighting by the Gaussian distribution, when a human gazes at a target pixel of an image (for example, the identification image 33), an apparent density of the target pixel felt by a human is obtained by a density value of a pixel around the target pixel. be able to.

The weighting mask 60 multiplies the density value of each pixel of the superimposed image by a weighting factor corresponding to each pixel to obtain a sum, and divides the sum by the sum of the weighting factors to obtain a target pixel. Is calculated as the pixel value of interest. That is, the target pixel value calculated by the weighting mask 60 changes according to the total density value of the pixels constituting the character (the identification character 32 in this embodiment) in the area near the target pixel. The target pixel value corresponds to target pixel information in the present invention.

[0030] For example, the pixel (x _1, y ₁₎ ~ pixel (x _5, y ₅₎
Weighting mask 6 on the image composed of 5 × 5 pixels
When superimposed 0, the target pixel value of the target pixel (x _3, y ₃₎ are calculated as follows.

Target pixel value = [sum of (pixel density value × weight coefficient)] ÷ (sum of weight coefficient) = ｛[(x _3, y
₃ ) × 1.0] + [(x _2, y ₂ ) × 0.5] + [(x _2, y ₃ )
× 0.5] +... + _{[(X 4, y 4) ×} 0.5 ] +.
+ _{[(X 1, y 1) ×} 0.1 ] + _{[(x 1, y 2) ×} 0.5 ] +
... + _{[(x 5, y 5) ×} 0.1 ]} ÷ (1.0 + 0.5
× 8 + 0.1 × 16)

In this embodiment, the size of the weighting mask is about twice the font size (5 × in this description).
(5 elements), but the present invention is not limited to this, and a weighting mask of any size can be generated. Also, the weighting factor set for each pixel of the weighting mask is not limited to the Gaussian distribution, and any weighting factor can be set.

Step S4 (Calculate each pixel value of interest in the identification image) The CPU 1 superimposes the central element 61 of the weighting mask 60 (hereinafter simply referred to as "mask 60") on each pixel of the identification image 33 sequentially. By calculating, the target pixel value of each pixel in the identification image 33 is calculated. Step S4
Corresponds to the function of the target pixel information calculation means in the present invention.

Specifically, the character "E" of the identification character 32 is
FIG. 6 shows a part of the displayed identification image 33.
It will be described using FIG. As shown in FIG. 6, including the character "E"
A part of the identification image 33 is, for example, a pixel (x_1,y₁) To pixel
 (x_Ten,y₈) Of 10 × 8 pixels
In this case, the central element 61 of the mask 60 is_1,y ₁)
From the pixel (x_Ten,y₈), And
Calculates the pixel value of interest for each pixel when overlaid on the pixel
I do.

For example, as shown in FIG.
The central element 61 is a pixel (x_7,y_Three), The mask 60
Pixels constituting the character "E"
 (x _Five,y_Three)_, (x_6,y_Three), (X_7,y_Three), (X_8,y_Three),
(x_6,y_Four), (X_6,y_Five) And their density values are
It is "1". Pixels in other parts are density values
It is "0". Therefore, weighted by the mask 60
The sum of the density values obtained is the pixel (x_Five,y_Three)_, (x_6,y_Three),
(x_7,y_Three), (X_8,y_Three), (X_6,y_Four), (X_6,y_Five) To
The weighted coefficient of the corresponding mask 60 is multiplied by each density value.
is there. That is, the sum of the weighted density values = [1 (density)
Degree value) × 0.1 (weight coefficient) × 2 (number of corresponding pixels)]
+ [1 × 0.5 × 3] + [1 × 1.0 × 1] = 2.7
is there. Also, the sum of the weighting coefficients = 0.1 × 16 + 0.5 ×
8 + 1.0 × 1 = 6.6. Therefore, the pixel (x
_7,y_Three) = 2.7 ÷ 6.6 ≒ 0.40
You. Hereinafter, this target pixel value “0.40” is calculated as a percentage.
The pixel value of interest is represented as “40%”.

On the other hand, as shown in FIG.
If the heart element 61 is a pixel (x_Ten,y ₈)
The mask 60 protrudes outside the identification image 33. in this case
, The weight coefficient of the mask 60 in the protruding part
Is calculated without calculating the pixel (x_Ten,y₈)
calculate. Specifically, the pixel (x_Ten,y₈) To mask 60
If there is a central element 61, the identification image 33 and the mask
Consider only those pixels where 60 overlaps. Identification image
In an area where the image 33 and the mask 60 overlap,
The pixels that make up the character "E" are pixels (x_8,y₇)_, (x_9,
y₇), Their density value is “1” and the other pixels
Is "0". Therefore, by the mask 60
Sum of weighted density values = [1 × 0.1 × 1] +
[1 × 0.5 × 1] = 0.6. Also, the weight coefficient
Sum = 0.1 × 5 + 0.5 × 3 + 1.0 × 1 = 3.0
is there. Therefore, the pixel (x_Ten,y₈Target pixel value of) =
0.6 ÷ 3.0 = 0.2 = 20%.

By the above-described calculation of the target pixel value, the target pixel values of all the pixels of the identification image 33 are obtained. In addition, the target pixel value of each pixel of the identification image 33 indicates that the higher the value of the target pixel value, the larger the number of pixels constituting a character in the area near the pixel or the higher the total density value of the pixels. Therefore, in order to make the characters easy to see, as will be described later, it can be seen that the higher the value of the target pixel value, the lower the density value of the pixel of the background image corresponding to the target pixel value should be. When each pixel of the identification image 33 is multi-valued, the multi-valued density value is multiplied by a weight coefficient instead of the above-described density value “1”.

Step S5 (Acquire Density Value of Each Pixel of Background Image) The CPU 1 calls the background image 31 stored in the work memory 3 and acquires the density value of each pixel of the background image 31 as a percentage. For example, when each pixel of the background image 31 is represented by 16 gradations, and a specific pixel has a value for 8 gradations, the specific pixel is 8 ÷ 16.
= 0.5 = 50%. By performing the same calculation for all the pixels of the background image 31, the density value of each pixel can be obtained. The higher the value of the density value of each pixel of the background image 31, the higher the density.

Step S6 (Specify a pixel to be adjusted) The CPU 1 compares an arbitrary threshold value set in advance with a target pixel value of each pixel of the identification image 33, and determines a pixel having a target pixel value equal to or larger than the threshold value. Is selected from the pixels of the identification image 33. The arbitrary threshold is input by the operator in advance using, for example, the keyboard 5 or the mouse 6, and can be an arbitrary value. For example, if the threshold is "3
If “0%” is set, the CPU 1 selects a target pixel value having a value of “30%” or more from the target pixel value of each pixel of the identification image 33, and selects a pixel having the target pixel value. I do. Further, pixels of the background image 31 corresponding to those pixels of the identification image 33 are specified as adjustment target pixels. Step S6 corresponds to the function of the threshold value selecting means in the present invention.

That is, by selecting a pixel value of interest equal to or greater than an arbitrary threshold value, for example, when the pixel value of interest is equal to or greater than the threshold value, the pixels constituting the character are located in the vicinity of the pixel having the pixel value of interest. Since there are many, the background image 3
This indicates that it is necessary to reduce the density value of one pixel to make the characters easier to see. On the other hand, if the pixel value of interest is less than the threshold value, the density value of the pixel of the background image 31 is adjusted because there are not many pixels forming characters, line drawings, etc. in the vicinity of the pixel having the pixel value of interest. Indicates that there is no need. That is, in step S6, only the pixels for which the density value of the pixels of the background image 31 need to be adjusted are
Is specified based on the pixel value of interest.

Step S7 (Adjust the density value of the background image) The CPU 1 calculates the adjusted density value for the pixel to be adjusted of the background image 31, the target pixel value of the pixel of the identification image 33 corresponding to the pixel to be adjusted, and the It is calculated according to the density value of the pixel and the adjustment coefficient. This adjusted density value is, for example,
It can be calculated by (the density value of the adjustment target pixel) − (the pixel value of interest) × (adjustment coefficient). Here, the adjustment coefficient is set in advance according to the density value of the adjustment target pixel. For example, the density values “0%” to “30” of the adjustment target pixel
%, The adjustment coefficient is “1.0”, and the density value is “30%” to
At “50%”, the adjustment coefficient is “1.2” and the density value is “50”.
% ”To“ 80% ”, the adjustment coefficient is“ 1.4 ”,.
Is set. Here, by setting the adjustment coefficient to be larger as the density value of the adjustment target image of the background image 31 is higher, the degree to which the density value is adjusted is higher for pixels having a higher density of the background image, and The lower the density of the pixel, the smaller the degree to which the density value is adjusted. In other words, when the density of the background image is high, it is necessary to make a large adjustment,
This is because when the concentration is low, there is no need to adjust much.

The CPU 1 calculates adjusted density values for all the adjustment target pixels, and replaces the density values of the respective adjustment target pixels with the adjusted density values. Step S7
Corresponds to the function of the background image density adjusting unit and the adjusting unit in the present invention, and the adjustment coefficient corresponds to the adjustment value in the present invention.

Specifically, when the density value of a certain adjustment target pixel is “80%” and the pixel density of interest of the pixel of the identification image 33 corresponding to the adjustment target pixel is “45%”, The adjusted density value = 80−45 × 1.4 = 17%. The CPU 1 sets the density value of a certain adjustment target pixel to “80”.
% "To" 17% ". Background image 3
The adjustment of the density value is similarly performed for all the adjustment target pixels of No. 1.

When the adjustment of the density values for all the adjustment target pixels is completed, the CPU 1 stores the background image 31 after the density adjustment in the work memory 3 as a new background image.

Step S8 (Display New Page Image) The CPU 1 calls a new background image and each identification character 32 from the work memory 3, and the identification character 32 is formed on the new background image. A new page image is generated, and the new page image is displayed on the monitor 9. A series of processing is terminated by displaying a new page image on the monitor 9. However, when processing is performed using a different size weighting mask or processing is performed on another type of page image, steps S2 to S7 are performed. Is repeated.

FIG. 8 shows a new page image displayed on the monitor 9 in step S8. As shown in FIG. 8, the new page image 40 is displayed with the respective identification characters 32 superimposed on the new background image 41. This background image 41 has a (target pixel value) ×
The processing is performed in pixel units so that the density difference between the background image 41 and the identification character 32 increases as the (adjustment coefficient) increases. That is, the density of the background image is reduced only in the vicinity of each of the identification characters 32, so that the identification characteristics of the identification characters 32 are improved and the loss of the background information is minimized. Note that the broken line surrounding the vicinity area 35 in FIG. 8 is shown for convenience of description, and is not actually displayed.

The present invention can be modified as follows. (1) In the above-described embodiment, the density value of each pixel of the background image 31 is adjusted based on the target pixel value multiplied by the adjustment coefficient, but, for example, the adjustment value is added to the target pixel value. Based on this, the density value of the pixel can be adjusted.

First, similarly to the case of setting the adjustment coefficient in the above-described embodiment, an adjustment value to be added to the target pixel value is set in advance according to the density value of the adjustment target pixel. For example,
When the density value of the adjustment target pixel is "0%" to "30%", the adjustment value is "8%", and when the density value is "30%" to "50%", the adjustment value is "10%", and the density value is "50%". For "~ 80%", the adjustment value is set to "15%",.... Also in this case, as the density value of the pixel of the background image 31 increases,
Set so that the adjustment value is large.

For example, if the density value of the pixel to be adjusted is “80”
% "And the identification image 33 corresponding to the pixel to be adjusted.
If the target pixel value of the pixel is “45%”, the density adjustment target value = 80− (45 + 15) = 20%. Based on this density adjustment target value “20%”, adjustment is made so that the density value of the adjustment target pixel is reduced from “80%” to “20%”. A new background image 31 is obtained by similarly adjusting the density value for all the adjustment target pixels of the background image 31.

The adjustment value to be added to the above noted image value is
By setting the adjustment value to be larger as the density value of the adjustment target image of the background image 31 is higher, the degree of adjustment of the density value is higher for a pixel having a higher density of the background image, that is, the density value is smaller. To (2) In the above-described embodiment, the target pixel value is selected based on the threshold, and the adjustment target pixel of the background image 31 for adjusting the density value is specified. However, the present invention is not limited to this. The density adjustment can be performed on all the pixels of the background image 31 without specifying the adjustment target pixel.

(3) In the above-described embodiment, the density value of each pixel of the background image 31 is adjusted based on the value obtained by multiplying the pixel value of interest by the adjustment coefficient or by adding the adjustment value. The density value of each pixel of the background image can be adjusted according to only the target pixel value. In this case, the adjusted density value can be obtained from the density value of the adjustment target pixel−the target pixel value.

[0052]

As is apparent from the above description, according to the first aspect of the present invention, the density difference between the background image and the character is increased only in the vicinity of the character based on the target pixel information. As described above, since the density of the background image is adjusted on a pixel-by-pixel basis, the loss of background information such as the color and pattern of the background image is minimized, and the discrimination of characters superimposed on the background image is improved. Can be.

According to the invention described in claim 2, according to claim 1
Can be suitably implemented.

According to the third aspect of the present invention, the degree of adjustment of the density information of each pixel of the background image can be changed depending on the magnitude of the adjustment value applied to the target pixel information. Adjustments can be made, and the character recognition can be further improved.

According to the fourth aspect of the present invention, the target pixel information is selected based on an arbitrary threshold value, so that only the pixels for which the density adjustment is required are selected from the respective pixels of the background image. The density information can be adjusted.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an image display device according to an embodiment.

FIG. 2 is a flowchart illustrating a flow of a process performed in the embodiment.

FIG. 3 is a diagram showing a page image.

FIG. 4 is a diagram showing an identification image including an identification character.

FIG. 5 is a diagram showing a weighting mask.

FIG. 6 is a diagram illustrating a state in which a weighting mask is superimposed on an identification image.

FIG. 7 is a diagram illustrating a state in which a weighting mask is superimposed on an end of an identification image.

FIG. 8 is a diagram illustrating a state of a page image displayed on the image display device.

FIG. 9 is a diagram illustrating a display state of a page image according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... CPU 2 ... Program memory 3 ... Work memory 4 ... External storage device 5 ... Keyboard 6 ... Mouse 7 ... Printer 8 ... Communication device 9 ... Monitor 10 ... Network 30 ... Page image 31 ... Background image 32 ... Identification character 33 ... Identification Image 33a: Pixel 60: Weighting mask 61: Central pixel

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/445 G06F 15/66 450 5/66 H04N 1/40 101E (72) Inventor Hiroshi Higashi Kyoto, Kyoto 1-chome Tenjinkita-cho, Horikawa-dori-Terauchi, Kamigyo-ku, City 1 Dainippon Screen Mfg. Co., Ltd. Address 1 Dainippon Screen Mfg. Co., Ltd.

Claims (4)

[Claims] 1. An image display method for displaying characters superimposed on a background image, wherein each pixel of interest in an identification image, which is a raster image of the characters, is included in a region near the pixel of interest. Calculating target pixel information that changes according to the total density information of the group; and identifying the identification image so that a density difference between the character and the background image increases according to each target pixel information of the identification image. A step of adjusting density information of each pixel of the background image corresponding to each pixel of the above, and a step of superimposing and displaying the characters on the background image in which the density information has been adjusted. Display method. 2. An image display apparatus for displaying a character superimposed on a background image, wherein each pixel of interest in an identification image, which is a raster image of the character, is included in a region near the pixel of interest. A pixel-of-interest information calculating means for calculating pixel-of-interest information that changes according to the total density information of the group; and a density difference between the character and the background image increases according to each pixel of interest of the identification image. Background image density adjusting means for adjusting density information of each pixel of the background image corresponding to each pixel of the identification image; display means for superimposing and displaying the characters on the background image in which the density information has been adjusted; An image display device comprising: 3. The image display device according to claim 2, wherein the background image density adjustment unit includes a density difference between the character and the background image in each piece of target pixel information calculated by the target pixel information calculation unit. An image display device comprising an adjustment unit for applying an adjustment value for changing a degree of the image, and adjusting density information of each pixel of the background image according to each piece of target pixel information on which the adjustment value is applied by the adjustment unit. . 4. The image display device according to claim 2, wherein the background image density adjusting unit selects each target pixel information calculated by the target pixel information calculating unit using an arbitrary threshold. An image display device comprising a selection unit, and adjusting density information of a pixel of the background image corresponding to a pixel of the target pixel information selected by the threshold selection unit.