JP3984525B2 - Image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display apparatus that performs image enlargement / reduction processing and displays an enlarged / reduced image.
[0002]
[Prior art]
Devices for reducing the image vertically or horizontally are known. In order to reduce the memory capacity required for the image reduction processing and improve the processing speed, this apparatus uses a plurality of filters used for reducing the original image data transferred in blocks. The calculation result (work data) by each filter is divided and input / output, and the calculation result for the pixel position data necessary after reduction is output (see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-150281
[Problems to be solved by the invention]
Now, when the image is subjected to the vertical enlargement / reduction process in the vertical filter part and then the horizontal enlargement / reduction process in the horizontal filter part, and the obtained enlarged / reduced image is to be displayed on the screen, If the start time of the filter process is fixed, the display may be distorted when the vertical reduction ratio is increased or when an image with a small display size is displayed at the bottom of the screen.
[0005]
An object of the present invention is to improve image display performance without improving the processing performance of the vertical filter section.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an image display device according to the present invention performs vertical scaling processing on an image and generates a vertical scaled image, and the obtained vertical scaled image A first storage unit for holding the image, a horizontal filter unit for performing horizontal enlargement / reduction processing on the image in the first storage unit to generate a horizontal enlarged / reduced image, and the obtained horizontal To specify the second storage unit for holding the enlarged / reduced image, the display unit for displaying the image of the second storage unit, the activation time of the vertical filter unit, and the activation time of the horizontal filter unit The filter activation time control unit is provided. The vertical filter unit and the horizontal filter unit are activated asynchronously. In addition, the filter activation time control unit switches the activation time of the horizontal filter unit according to the vertical display size of the horizontally enlarged / reduced image displayed on the display unit. As a result, even when an image with a small display size is displayed at the bottom of the screen, the data before being displayed is not overwritten by the horizontal filter section, and display disturbance is prevented.
[0007]
The filter activation time control unit switches the activation time of the vertical filter unit according to the enlargement / reduction ratio of the enlargement / reduction process in the vertical direction performed by the vertical filter unit. Thereby, even when the reduction ratio in the vertical direction is increased, the processing of the horizontal filter unit does not proceed before the vertical filter unit, and the vertical reduction process can be performed without disturbing the display.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 shows a configuration example of an image display apparatus according to the present invention. The image display apparatus shown in FIG. 1 performs vertical enlargement / reduction processing on the input image 101 and holds the vertical filter unit 103 for generating the vertical enlargement / reduction image 102 and the obtained vertical enlargement / reduction image 102. And a horizontal filter unit 107 for performing horizontal enlargement / reduction processing on the vertical enlarged / reduced image 105 of the first storage unit 104 and generating a horizontal enlarged / reduced image 106. The second storage unit 108 for holding the obtained horizontal enlarged / reduced image 106, the display unit 110 for displaying the horizontal enlarged / reduced image 109 of the second storage unit 108, and the vertical filter unit 103 The filter activation time control unit 111 is used to specify the activation time and the activation time of the horizontal filter unit 107.
[0011]
The vertical filter unit 103 is activated once for each input image 101. The horizontal filter unit 107 is activated twice in total for the first field and the second field for one vertical enlarged / reduced image 105, and performs horizontal enlargement / reduction processing. Similarly, the display unit 110 is activated twice in total for the first field and the second field, and each performs display processing.
[0012]
The first storage unit 104 can hold one frame of the vertically enlarged / reduced image 102 generated by the vertical filter unit 103, and is written from the vertical filter unit 103 in order from the head and from the horizontal filter unit 107. Are read sequentially. The second storage unit 108 can hold the horizontal enlarged / reduced image 106 generated by the horizontal filter unit 107 for one field, which is sequentially written from the top from the horizontal filter unit 107 and from the top from the display unit 110. Read sequentially.
[0013]
Here, the maximum size of the input image 101 is 720 pixels horizontally and 480 pixels vertically, and the maximum size of the vertically enlarged / reduced images 102 and 105 and horizontally enlarged / reduced images 106 and 109 is also 720 pixels horizontally and 480 pixels vertically. Further, the enlargement / reduction ratio can be arbitrarily set from 1/4 to 4 times in both the vertical direction and the horizontal direction. The image display position on the display unit 110 can also be set to an arbitrary position.
[0014]
The processing performance of the vertical filter unit 103 is proportional to the vertical size of the input image 101. When the period of the vertical synchronization signal (VSYNC) is 1.0 V, an image with a vertical size of 480 pixels is 1 in 0.9 V period. It is possible to process frames. The processing amount of the horizontal filter unit 107 is proportional to the vertical size of the vertically enlarged / reduced image 105, and an image having a vertical size of 480 pixels can be processed for one field in a 0.5V period. Shall. Note that the vertical filter unit 103 and the horizontal filter unit 107 operate in a time-sharing manner, and each of them is assumed to be half the processing performance shown above when executed simultaneously.
[0015]
2 shows the relationship between the vertical enlargement / reduction ratio and the activation time of the vertical filter unit 103, and FIG. 3 shows the relationship between the vertical display size and the first and second field activation times of the horizontal filter unit 107, respectively. The filter activation time control unit 111 designates activation times of the vertical filter unit 103 and the horizontal filter unit 107 in accordance with FIGS. 2 and 3. When the vertical enlargement ratio is from 4 times to 1 time, the vertical filter unit 103 starts up at 0.4V. In the 0.5V period, the vertical filter unit 103 operates alone, and in the subsequent 0.8V period, the vertical filter unit 103 and the horizontal filter unit 107 operate in a time division manner. When the vertical enlargement ratio is less than 1 to 3/4, the vertical filter unit 103 starts at 0.3V. In the 0.6V period, the vertical filter unit 103 operates alone, and in the subsequent 0.6V period, the vertical filter unit 103 and the horizontal filter unit 107 operate in a time division manner. When the vertical enlargement ratio is less than 3/4 to 1/2, the vertical filter unit 103 starts up at 0.2V. In the 0.7V period, the vertical filter unit 103 operates alone, and in the subsequent 0.4V period, the vertical filter unit 103 and the horizontal filter unit 107 operate in a time division manner. When the vertical enlargement ratio is less than 1/2 times to 1/4 times, the vertical filter unit 103 starts up at 0.1V. In the subsequent 0.2 V period, the vertical filter unit 103 and the horizontal filter unit 107 operate in a time division manner.
[0016]
FIG. 4 shows an operation example of the image display apparatus of FIG. As shown in FIG. 4, the image display device operates periodically, and the cycle is 2.0V. In this example, it is assumed that the input image 101 having 720 pixels in the horizontal direction and 480 pixels in the vertical direction is displayed in the center of the screen by 1 time in the vertical direction and 1 time in the horizontal direction. The vertical filter unit 103 is activated to 0.4V according to FIG. According to FIG. 3, the horizontal filter unit 107 starts the horizontal expansion / reduction process for the first field at 0.0V and the horizontal expansion / reduction process for the second field at 0.9V.
[0017]
5A and 5B show the read / write process (first and second fields) of the first storage unit 104 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the vertically enlarged / reduced images 102 and 105. A solid line indicates writing by the vertical filter unit 103, and a dotted line indicates reading by the horizontal filter unit 107. In either of FIGS. 5A and 5B, reading does not overtake writing, so the horizontal filter unit 107 does not perform horizontal enlargement / reduction processing on erroneous data.
[0018]
FIG. 6 shows a read / write process of the second storage unit 108 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the horizontally enlarged / reduced images 106 and 109. A solid line indicates writing by the horizontal filter unit 107, and a dotted line indicates reading by the display unit 110, respectively. According to FIG. 6, since reading does not overtake writing, display unit 110 does not display incorrect data.
[0019]
FIG. 7 shows another operation example of the image display device of FIG. In this example, with respect to the input image 101 having 720 horizontal pixels and 480 vertical pixels, the vertical direction is reduced by a factor of 1/4 and the horizontal direction by a factor of 1/4. Assume that an image of a pixel is displayed. The vertical filter unit 103 is activated to 0.1 V according to FIG. According to FIG. 3, the horizontal filter unit 107 starts the horizontal expansion / reduction process for the first field at 0.0V and the horizontal expansion / reduction process for the second field at 0.9V.
[0020]
FIGS. 8A and 8B show the read / write process (first and second fields) of the first storage unit 104 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the vertically enlarged / reduced images 102 and 105. A solid line indicates writing by the vertical filter unit 103, and a dotted line indicates reading by the horizontal filter unit 107. In either of FIGS. 8A and 8B, reading does not overtake writing, so the horizontal filter unit 107 does not perform horizontal enlargement / reduction processing on erroneous data.
[0021]
On the other hand, the alternate long and short dash line in FIGS. 8A and 8B indicates the first storage by the vertical filter unit 103 when the activation time of the vertical filter unit 103 is set to 0.4 V as in the example of FIG. Writing to the unit 104 is shown. In this case, as can be seen from the fact that the alternate long and short dash line in FIG. 8A intersects the dotted line, the horizontal filter unit 107 finishes the process earlier than the vertical filter unit 103. The horizontal filter unit 107 reads out the data before the vertical filter unit 103 writes and performs enlargement / reduction processing. Therefore, an incorrect image is finally displayed, leading to display disturbance. However, according to the present invention, since the vertical filter unit 103 is activated to 0.1 V according to FIG. 2 as described above, the display is not disturbed.
[0022]
FIG. 9 shows a reading / writing process of the second storage unit 108 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the horizontally enlarged / reduced images 106 and 109. A solid line indicates writing by the horizontal filter unit 107, and a dotted line indicates reading by the display unit 110, respectively. According to FIG. 9, since reading does not overtake writing, the display unit 110 does not display erroneous data.
[0023]
FIG. 10 shows still another operation example of the image display apparatus of FIG. In this example, it is assumed that the input image 101 of 90 pixels in the horizontal direction and 60 pixels in the vertical direction is displayed at the bottom of the screen at 1 time in the vertical direction and 1 time in the horizontal direction. The vertical filter unit 103 is activated to 0.4V according to FIG. In accordance with FIG. 3, the horizontal filter unit 107 starts the horizontal expansion / reduction process for the first field at 0.0V and the horizontal expansion / reduction process for the second field at 0.0V.
[0024]
FIGS. 11A and 11B show the read / write process (first and second fields) of the first storage unit 104 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the vertically enlarged / reduced images 102 and 105. A solid line indicates writing by the vertical filter unit 103, and a dotted line indicates reading by the horizontal filter unit 107. In either of FIG. 11A and FIG. 11B, reading does not overtake writing, so the horizontal filter unit 107 does not perform horizontal enlargement / reduction processing on erroneous data.
[0025]
FIG. 12 shows a read / write process of the second storage unit 108 corresponding to the operation example of FIG. The horizontal axis represents time, and the vertical axis represents the vertical position of the horizontally enlarged / reduced images 106 and 109. A solid line indicates writing by the horizontal filter unit 107, and a dotted line indicates reading by the display unit 110, respectively. According to FIG. 12, since reading does not overtake writing, display unit 110 does not display incorrect data.
[0026]
On the other hand, the alternate long and short dash line in FIG. 12 indicates that the horizontal filter unit 107 writes to the second storage unit 108 when the second field activation time of the horizontal filter unit 107 is 0.9 V as in the example of FIG. Show. In this case, as can be seen from the fact that the alternate long and short dash line and the dotted line in FIG. 12 intersect, as a result of the second field being written by the horizontal filter unit 107 too early, the first field before the display unit 110 reads it out. Is overwritten by the horizontal filter unit 107. Therefore, an incorrect image is displayed, which leads to display disturbance. However, according to the present invention, as described above, the second field processing of the horizontal filter unit 107 is activated to 0.0 V in accordance with FIG.
[0027]
【The invention's effect】
As described above, according to the present invention, by controlling the start time of the vertical filter processing and the start time of the horizontal filter processing according to the value of the vertical enlargement / reduction ratio and the value of the vertical display size, respectively, Can be enlarged / reduced to an arbitrary size and displayed at an arbitrary position.
[0028]
Thus, since the image display performance can be improved without improving the processing performance of the vertical filter section, a great effect can be obtained both in terms of cost and function.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration example of an image display device according to the present invention.
FIG. 2 is a diagram illustrating a relationship between a vertical enlargement / reduction ratio and a startup time of a vertical filter unit in the image display apparatus of FIG.
3 is a diagram illustrating a relationship between a vertical display size and first and second field activation times of a horizontal filter unit in the image display apparatus of FIG. 1;
4 is a timing chart showing one operation example of the image display device in FIG. 1; FIG.
FIGS. 5A and 5B are timing chart diagrams showing a read / write process of the first storage unit in FIG. 1 corresponding to the operation example of FIG. 4;
6 is a timing chart showing a read / write process of the second storage unit in FIG. 1 corresponding to the operation example of FIG. 4;
7 is a timing chart illustrating another operation example of the image display apparatus in FIG. 1; FIG.
8A and 8B are timing chart diagrams showing a reading / writing process of the first storage unit in FIG. 1 corresponding to the operation example of FIG. 7;
9 is a timing chart showing a read / write process of the second storage unit in FIG. 1 corresponding to the operation example of FIG. 7;
10 is a timing chart showing still another operation example of the image display device in FIG. 1. FIG.
11A and 11B are timing charts showing a reading / writing process of the first storage unit in FIG. 1 corresponding to the operation example of FIG. 10;
12 is a timing chart showing a read / write process of the second storage unit in FIG. 1 corresponding to the operation example of FIG. 10;
[Explanation of symbols]
101 Input Image 102 Vertical Enlarged Reduced Image 103 Vertical Filter Unit 104 First Storage Unit 105 Vertical Enlarged Reduced Image 106 Horizontal Enlarged Reduced Image 107 Horizontal Filter Unit 108 Second Storage Unit 109 Horizontal Enlarged Reduced Image 110 Display Unit 111 Filter Activation Time Control unit

Claims (2)

A vertical filter unit for performing vertical enlargement / reduction processing on the image and generating a vertical enlargement / reduction image;
A first storage unit for holding the vertically enlarged / reduced image;
A horizontal filter unit for performing horizontal enlargement / reduction processing on the image in the first storage unit to generate a horizontal enlarged / reduced image;
A second storage unit for holding the horizontally enlarged / reduced image;
A display unit for displaying an image of the second storage unit;
A filter activation time control unit for designating the activation time of the vertical filter unit and the activation time of the horizontal filter unit ;
The image display device characterized in that the filter activation time control unit switches the activation time of the horizontal filter unit in accordance with a vertical display size of the horizontal enlarged / reduced image displayed on the display unit. The image display device according to claim 1,
The image display device according to claim 1, wherein the filter activation time control unit switches the activation time of the vertical filter unit according to an enlargement / reduction ratio of a vertical enlargement / reduction process performed by the vertical filter unit.

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