JP2001086470A - Video reducing/enlarging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide video matched to the aspect ratio of the screen of a display device by reducing/enlarging entire video into any arbitrary size. SOLUTION: A video signal is written in a memory 103 by a write clock from an input terminal 118. A clock generating circuit 119 supplies a read clock having about 4/3-fold frequency of the write clock to the memory 103. A vertical enlargement control circuit 110 reads the video signal out of the memory 103 in a line cycle corresponding to an enlargement scale. In the similar cycle, the write of a one-line memory 105 is stopped and the line delay output of the output signal of the memory 103 is provided. According to a control signal from the vertical enlargement control circuit 110, a vertical interpolating circuit 106 prepares a scan line signal through interpolating operation. A horizontal direction is similarly controlled by a horizontal enlargement control circuit 113.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital processing of a video signal, and more particularly, to compressing a video to an arbitrary size even when the aspect ratio of a video obtained by the video signal is different from that of a screen in a display device. , By enlarging and matching the aspect ratio of the screen of the display device,
The present invention relates to an image compression / expansion device capable of displaying an image on a screen without a sense of incongruity.

[0002]

2. Description of the Related Art A test broadcast of a high-definition television started in 1991, and a receiver having a screen aspect ratio of 16: 9 has begun to be widely used for home use. For a receiver having a screen aspect ratio of 16: 9, it is important to spread the compatibility with conventional broadcasting, and how to convert the aspect ratio of conventional broadcasting to 16: 9 is a major issue. ing. Furthermore, so-called letterbox video (the video has various aspect ratios), which is the size of a large number of movies in recent package software and the like, that is, the video has black bands above and below and has an overall aspect ratio of 4: 3. ) Means that, when projected on a display device having an aspect ratio of 16: 9, an aspect ratio close to 16: 9 can be obtained by enlarging in the vertical direction. Has become.

For example, in Japanese Patent Application Laid-Open No. 1-194784, an image is compressed in the horizontal direction by changing a writing frequency and a reading frequency of a line memory, and an aspect ratio of 4: 9 is set in a 16: 9 aspect ratio screen. : 3, a method of fitting an image and a method of vertically expanding an image by changing the output amplitude of a deflection circuit to cut and display a part of the upper and lower images are disclosed.

In Japanese Patent Application Laid-Open No. Hei 3-11891,
There is disclosed a technique for performing vertical enlargement of an image by digital signal processing. FIG. 2 shows a configuration in the proposed example in which a scanning line is interpolated by digital signal processing and a video is enlarged in a vertical direction.

In FIG. 2, 201 and 202 are input and output terminals for digitized video signals, 203 is a memory having a capacity of at least about 120 lines, 20
4 is a one-line memory, 205 and 206 are ROM tables for multiplying an input signal by a coefficient, 207 is an adder, 208 is an input terminal of a control signal of the memory 203, 209 is a ROM 20
An input terminal for a control signal for switching between tables 5,206.

In this proposed example, the memory 203 is controlled so as to read the same line again at a predetermined line cycle in accordance with a control signal from the input terminal 208. As a result of delaying the one-line video signal by the one-line memory 204, two upper and lower scanning line signals are supplied to the ROMs 205 and 206, multiplied by a coefficient in the ROM table selected by the control signal from the input terminal 209, and added. A signal having a correct scanning line center of gravity can be obtained from the detector 207.

In the enlarged image obtained in this manner, the interval between the scanning lines does not change in the progressive scanning signal as compared with the case in which the signal is enlarged by changing the output amplitude of the deflection circuit. A high-quality image can be obtained also in the device.

As described above, various schemes have been devised to display an image having an aspect ratio of 4: 3 on a screen having an aspect ratio of 16: 9.

[0009]

The two proposals described above are excellent as methods for displaying an image having an aspect ratio of 4: 3 on a screen having an aspect ratio of 16: 9. However, there are various aspect ratios of movie software letterbox images which are often seen in recent package software, and these are considered to be optimal for display devices having a screen aspect ratio of 16: 9. It has become difficult to fit the size.

In addition, the aspect ratio, which accounts for the majority, is 4: 3.
In the method of compressing and displaying the video, the screen may be burned, particularly in a projection type display device.

An object of the present invention is to solve the above-mentioned problems of the prior art, to reduce or enlarge the entire image to an arbitrary size,
It is an object of the present invention to provide an image reduction / enlargement device capable of obtaining an image that matches an aspect ratio of a screen of a display device.

It is another object of the present invention to provide an image reduction / enlargement apparatus capable of partially reducing or enlarging an image and obtaining an image that matches an aspect ratio of a screen of a display device.

[0013]

A video compression / expansion apparatus according to the present invention comprises a memory means for storing an input video signal, a horizontal compression / expansion means for compressing / expanding the input video signal in a horizontal direction, and the input / output means in a vertical direction. Vertical compression / expansion means for compressing / expanding a video signal; screen position specification means for specifying a position where the input video signal should be originally displayed; and designation of a compression or expansion ratio for each screen position where the input video signal is to be displayed. This can be achieved by having a compression / enlargement ratio setting unit that can specify a different compression ratio or enlargement ratio at each display position of the projected image.

[0014]

The memory means writes an input video signal in accordance with a write clock. At this time, the input video signal is managed and written in line units. On the other hand, the vertical compression / expansion means calculates a line cycle relating to reading of the memory means in accordance with the enlargement rate set by the compression / enlargement rate setting means, and outputs a control signal. Similarly, the horizontal compression / expansion means calculates the pixel period related to reading from the memory means in accordance with the magnification set by the compression / magnification setting means, and outputs a control signal. Also, a new read clock is generated from the input write clock in accordance with the horizontal compression ratio of the video.
The control signal from the vertical compression / expansion means and the horizontal compression / expansion means are combined with the read clock and supplied to the memory means.

In general, when displaying an image having an aspect ratio of 4: 3 with a correct circularity on a screen having an aspect ratio of 16: 9, a new read clock is written to the screen. If the frequency is set to 4/3 times the clock and the magnification is set to 1, the cycle of reading the same line again in line units of the memory means and the cycle of reading the same pixel again in pixel units become infinite. This simply means that the read clock has a frequency that is 4/3 times higher, and the video is compressed and displayed in the horizontal direction. Therefore,
A picture having an aspect ratio of 4: 3 is fitted on a screen having an aspect ratio of 16: 9.

When a large enlargement factor is set, for example, 4 /
In the case of triple, for example, the period of reading the same line again in line units by the vertical compression / expansion means is set to four lines, and the same line is read once every four lines. Also, the horizontal compression / expansion means similarly controls so that one out of every four pixels reads the same pixel, so that a video signal enlarged 4/3 times in both the vertical and horizontal directions is output.
An arbitrary enlargement ratio can be obtained by changing the designation of the set value. The screen position designation means designates a position where the input video signal should be displayed. At the designated display position, the compression / enlargement ratio setting means can set the compression / enlargement ratio.

[0017]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 101 denotes an input terminal of a digitized video signal;
02 is a video signal output terminal, 103 is a field memory, 104 is a vertical interpolation circuit, 105 is a one-line memory, 106 is a vertical interpolation circuit, 107 is a horizontal interpolation circuit, 108 is a pixel delay circuit, and 109 is a horizontal interpolation circuit , 1
10 is a vertical enlargement control circuit, 111 is a memory control circuit, 1
12 is a vertical interpolation coefficient generation circuit, 113 is a horizontal enlargement control circuit, 114 is an image delay control circuit, 115 is a horizontal interpolation coefficient generation circuit, 116 is a first delay circuit, 117 is a second delay circuit, and 118 is a write clock. Input terminal of 119
Is a read clock generation circuit, 120 is an input terminal for a vertical enlargement ratio setting value, 121 is an input terminal for a horizontal enlargement ratio setting value,
Reference numeral 122 denotes a memory control signal synthesis circuit.

In FIG. 1, a video signal input from an input terminal 101 is managed for each line by a write clock from an input terminal 118, and is sequentially written to a field memory 103. The clock generation circuit 119
A read clock having a frequency approximately 4/3 times that of the input write clock is generated and supplied to the field memory 103 through the synthesizing circuit 122. Therefore, the video signal obtained by compressing the video in the horizontal direction is stored in the field memory 103.
It will be read more. Vertical enlargement control circuit 110
Is the field memory 10 at the line cycle corresponding to the enlargement ratio.
3 is controlled via the synthesizing circuit 122 so as to read the video signal. Further, the writing of the one-line memory 105 included in the vertical enlargement circuit 104 is stopped at the same cycle,
A line delay output of the output signal of the field memory 103 is obtained. This is shown in FIG.

FIG. 3 is an explanatory diagram showing the appearance of scanning lines when the image is enlarged 4/3 times in the vertical direction. (B) is an output signal of the field memory 103, and the memory control circuit 11
1, the same scanning line is repeatedly read at the timing of the line reset (a). (C) is a one-line memory 10
5 of the line reset (a) by the write inhibit control signal of 5
Writing is stopped before the line, and the one-line memory 105
Is obtained. As a result, the vertical interpolation circuit 10
6 is supplied with signals of two upper and lower scanning lines. That is, (b) and (d) are always signals of adjacent scanning lines.

The vertical interpolation circuit 106 performs an interpolation operation (e) according to a control signal from the vertical enlargement control circuit 110.
To generate a scanning line signal.

FIG. 4 shows the configuration of the vertical enlargement control circuit 110. In FIG. 4, reference numeral 120 denotes an input terminal for an enlargement set value determined according to an enlargement ratio, 402 denotes an output terminal for an interpolation coefficient, 403 denotes an output terminal for a memory control signal, 404 denotes an input terminal for a pulse of one line cycle, and 405. Is an adder for adding the interpolation coefficient and the enlargement setting value input from the input terminal 120; 406 is a latch circuit for the output signal of the adder 405;
Reference numeral 07 denotes a latch circuit for the carry signal of the adder 405.

In this configuration example, the precision of the output interpolation coefficient is set to 8 bits. The adder 405 repeatedly adds the enlargement setting value and the fed back interpolation coefficient in accordance with the pulse input from the input terminal 404, so that new interpolation coefficients for each line are sequentially obtained. At this time, the carry signal of the adder 405 becomes a memory control signal for repeatedly reading the same line in the field memory 103. In the case of an 8-bit system, the relationship between the set value x of the enlargement ratio and the actual enlargement ratio z can be expressed by the following equation.

[0023]

[Mathematical formula-see original document] z = 256 / (256-x) By increasing the bit precision as can be seen from the above equation,
Theoretically, any magnification can be obtained.

On the other hand, the scanning line obtained by the vertical interpolation circuit 106 has a center of gravity at the position (g) with respect to the input video signal (video signal input from the input terminal 101) shown in FIG. Signal. By displaying this at the position (h) of the actual scanning line, a video signal in which the video is enlarged in the vertical direction can be obtained.

The horizontal enlargement can be performed in the same configuration as the vertical enlargement. The delay control signal generated by the horizontal enlargement control circuit 113 is supplied to the field memory 103 through the synthesis circuit 122. Field memory 10
In 3, control is performed to read out the same pixel again at a cycle corresponding to the magnification in accordance with the delay control signal to obtain a video signal in which the video is horizontally expanded. Furthermore, the horizontal enlargement circuit 1
At 07, horizontal interpolation is performed in accordance with the control signal from the horizontal enlargement control circuit 113 to obtain a video signal whose image is enlarged in the horizontal direction and whose center of gravity is uniform. Delay circuit 11
Reference numerals 6 and 117 are inserted for controlling the field memory 103 and adjusting the delay time between the pixel delay circuit 108 and the horizontal interpolation circuit 109.

As described above, in the present embodiment, by using the field memory 103 and the one-line memory 105, an image having an aspect ratio of 4: 3 and an aspect ratio of 1 are used.
With a simple circuit configuration, it is possible to temporarily compress an image in the horizontal direction so as to be displayed on a 6: 9 screen, and at the same time expand the image to an arbitrary size in the vertical and horizontal directions. For example, if the field memory HM530281 manufactured by Hitachi is used as the field memory, the same line can be repeatedly read using the line reset function, and the control is simplified.

FIG. 5 shows another embodiment of the present invention. FIG.
5, reference numeral 501 denotes a delay circuit for delaying a control signal of the field memory 103, reference numeral 502 denotes a delay circuit for interpolation coefficients, and other components are the same as those in the embodiment of FIG. This embodiment is different from the configuration of the embodiment of FIG. 1 in that the horizontal enlargement circuit 107 enlarges the image in the horizontal direction and then the vertical enlargement circuit 104 enlarges the image in the vertical direction. The operation of the circuit is the same as in the embodiment of FIG.

In this embodiment, the delay amounts of the delay circuits 116 and 117 are extremely small as compared with the embodiment shown in FIG. 1, and there is an effect that the circuit scale can be reduced. Since the delay circuits 501 and 502 are controlled on a line-by-line basis, there is almost no need to perform a delay by considering the control signal generation timing of the vertical enlargement control circuit 110. That is, by employing the configuration of the present embodiment, it is possible to provide a circuit that can be arbitrarily compressed and expanded with a smaller circuit scale.

FIG. 6 shows another embodiment of the present invention. FIG.
In FIG. 1, reference numeral 601 denotes a second horizontal enlargement control circuit having the same configuration as that of the horizontal enlargement control circuit 113;
This is the same as the embodiment. This embodiment is different from the embodiment of FIG. 1 in that a second horizontal enlargement control circuit 601 having a similar function is provided in addition to the horizontal enlargement control circuit 113. The operation of the circuit is the same as in the embodiment of FIG.

The first horizontal enlargement control circuit 113 controls the field memory 103 in accordance with the enlargement set value given from the input terminal 121, and obtains a video signal in which the image is enlarged in the horizontal direction. The second horizontal enlargement control circuit 601 includes a first
In response to the reset timing of the horizontal enlargement control circuit 113, the field memory 103 and the horizontal interpolation enlargement circuit 107
And a delay control signal for controlling the pixel delay circuit 108 in the horizontal interpolation enlargement circuit 107 and a coefficient value for controlling the horizontal interpolation circuit 109 are supplied. As a result, the delay circuit 1 required in the embodiment of FIG.
16 and 117 become unnecessary. Therefore, considering the delay time of the circuit, the delay circuits 116 and 117 in FIG.
By selecting one of the horizontal enlargement control circuits 601 having the smaller circuit scale, an optimum circuit can be configured.

In the above embodiment, the vertical enlargement control circuit 11
With 0 and the horizontal enlargement control circuit 113, the entire image could be compressed and enlarged to an arbitrary size in both the vertical and horizontal directions. This is because, when a horizontally long image such as a letterbox type movie is projected on a display device having a screen with an aspect ratio of 16: 9, among the images based on the video signal of the current system, the black band portion with no signal is reduced. There was a great effect in doing so. However, in a normal video having an aspect ratio of 4: 3, there is a large portion that becomes out of the screen and becomes invisible due to enlargement. Furthermore, depending on the size of the letterbox image, depending on its size, the left and right images become invisible by adjusting the upper and lower sizes, or the black bands remain at the top and bottom by adjusting the left and right sizes. And sometimes gave me a sense of discomfort. In addition, it has been pointed out that the black belt portion causes screen burn-in.

An embodiment which solves such a problem will be described with reference to FIG. That is, the present embodiment is an improvement of the vertical enlargement control circuit 110 and the horizontal enlargement control circuit 113 in the above-described embodiment, and FIG. 7 is a block diagram showing the configuration of the vertical enlargement control circuit 110.

In FIG. 7, reference numeral 701 denotes a vertical counter for counting the number of lines on the screen, reference numeral 702 denotes a numerical converter for converting the value of the vertical counter 701 according to a certain function, and the other components are the same as those in the configuration example of FIG. According to this embodiment, FIG.
Since the set value of the enlargement ratio from the input terminal 120 shown in the configuration example can be freely converted according to the setting of the numerical value converter 702 depending on the position on the screen, it is possible to enlarge an arbitrary position in the video at an arbitrary magnification. it can. Numeric converter 702
Can be configured by a logic circuit if it is a simple function. For a complicated function, a look-up table method using a ROM or the like may be employed. FIG. 8 shows an example of use of this embodiment.

FIG. 8A shows an image obtained by compressing an image based on an image signal of the current system in the horizontal direction and displaying the image on a screen having an aspect ratio of 16: 9. This image is of a landscape letterbox type, and its aspect ratio is almost 2:
1, the aspect ratio of the whole (the image and the black band portion) before compression is 4: 3. (B)
Is an enlarged version of (a) by 4/3 in both the vertical and horizontal directions, and the image in the horizontal direction almost matches in the 16: 9 screen. However, as described above, in this case, a black band part is left slightly above and below, resulting in an unnatural screen.

FIG. 7C shows a function in the numerical converter 702 shown in FIG. The vertical axis is the vertical counter 70
The horizontal axis indicates the enlargement ratio. This function gives a 4/3 magnification near the center of the screen, increases the magnification at the top and bottom edges of the screen, and sets the average vertical magnification to 3 /
It is doubled. Such a function is converted to a numerical converter 70
By defining in (2), as shown in (d), there can be provided an image which has no black band and fits on a screen having an aspect ratio of 16: 9. At this time, in the center part of the screen, since the enlargement ratios in the horizontal and vertical directions match, the image is displayed with the correct circularity, and the circularity changes only at the edge of the screen. Therefore, the sense of incongruity as a video is almost eliminated.

On the other hand, (e) shows a case where the image is enlarged by 3/2 times in both the vertical and horizontal directions. The size in the vertical direction matches the screen having the aspect ratio of 16: 9, but the image in the horizontal direction is A chipped portion will result. In this case, the concept of the numerical converter 702 described above is introduced for the horizontal enlargement control circuit 113. The input signal of the numerical converter 702 becomes a count value of a horizontal counter (not shown), and a function for determining the enlargement ratio is selected such that the enlargement ratio becomes smaller at both ends in the horizontal direction of the screen as shown in FIG. At this time, if the average enlargement ratio in the horizontal direction is set to be 4/3, all images can be accommodated on a screen having an aspect ratio of 16: 9 as shown in (g). Also in this case, as in (d), the image is distorted only at both ends in the horizontal direction, and the image has almost no discomfort.

As described above, in this embodiment, by introducing the numerical converter 702 shown in FIG. 7 and combining it with the circuit shown in FIG. Can be compressed and expanded
A screen with an aspect ratio of 16: 9 and an aspect ratio of 4:
3 and the letterbox image can be displayed without discomfort.

FIG. 9 shows still another embodiment of the present invention. In FIG. 9, reference numeral 901 denotes an input terminal of a video signal;
2 is a display having a screen with an aspect ratio of 4: 3,
An image processing circuit 903 performs signal processing such as Y / C separation on an input image signal and supplies the signal to a display 902.
Reference numeral 4 denotes a synchronization processing circuit for extracting a synchronization signal from a video signal;
Reference numeral 05 denotes a mode setting circuit for setting an enlargement / compression ratio of a video signal. Reference numeral 906 denotes a vertical deflection for outputting a vertical deflection current for driving the display 902 in accordance with a mode specified by the mode setting circuit 905 from an output signal of the synchronization processing circuit 904. A horizontal deflection circuit 907 for outputting a horizontal deflection current for driving the display 902 in accordance with a mode designated by the mode setting circuit 905 from an output signal of the synchronization processing circuit 904; and 908 and 909, a vertical deflection circuit 906
And a first and second deflection current correction circuits 910 for correcting the deflection current output of the horizontal deflection circuit 907, and a high voltage generation circuit 910.

The present embodiment is different from the above-described embodiment in that partial compression and expansion of an image are performed by a deflection circuit and a deflection current correction circuit. The vertical deflection circuit 906 generates a vertical sawtooth wave for driving the display 902 according to the vertical pulse from the synchronization processing circuit 904.
Similarly, the horizontal deflection circuit 907 generates a horizontal sawtooth driving the display 902 according to the horizontal pulse from the synchronization processing circuit 904. At this time, the vertical deflection circuit 906 and the horizontal deflection circuit 907
The inclination and phase of the generated sawtooth wave are changed according to the mode set by the step 5. Therefore, the image is entirely enlarged in the vertical and horizontal directions.

On the other hand, the first deflection current correction circuit 908 is connected to the vertical deflection circuit 906 and to the second deflection current correction circuit 9.
Reference numeral 09 applies a correction to the horizontal deflection circuit 907 to give a partial distortion to the sawtooth wave. Due to this correction, the slope of the sawtooth wave partially changes, and the expansion compression ratio of the image changes at each location on the screen.

The present embodiment is particularly effective when displaying an image in letter box format on a screen having an aspect ratio of 4: 3. FIG. 10 shows a usage example of this embodiment.

FIG. 10A shows a letterbox format image displayed on a screen having an aspect ratio of 4: 3. Letterbox video is expected to be widely used in the future by a method adopted in the second generation EDTV system. In the second-generation EDTV, high-definition information is inserted into upper and lower non-image portions, so that it is considered that some unnaturalness remains on a screen having an aspect ratio of 4: 3. FIG. 11B shows a technique in which the vertical deflection circuit 906 and the horizontal deflection circuit 907 are used to enlarge the image in the vertical and horizontal directions as a whole to reduce the area of the non-image area. However, the problem remains because there are portions that cannot be seen at the left and right ends. (C) uses the second deflection current correction circuit 909 to reduce the slope of the horizontal sawtooth wave at the left and right ends to compress the video,
The image is enlarged by increasing the inclination of the vertical sawtooth wave at the upper and lower ends using the deflection current correction circuit 908 of FIG. Therefore, almost all necessary images can be displayed. (D) shows distortion generated in a displayed image when the display method of (c) is adopted. The central part (A) has no distortion, and the distortion is the largest at the four corners (D).
And this is hardly a problem.

The method of the present embodiment is also effective when displaying on a screen having an aspect ratio of 16: 9 shown in FIG. In addition, the method is relatively simple as compared with the above-described method of changing the expansion / compression ratio by digital processing, and is particularly effective for an analog display device.

[0044]

According to the present invention, for example, when displaying an image having an aspect ratio of 4: 3 on a screen having an aspect ratio of 16: 9, the entire image can be reduced or enlarged to an arbitrary size. Therefore, an image matching the aspect ratio of the screen can be obtained, and the image can be displayed on the screen without a sense of incongruity.

Further, since the image can be partially reduced or enlarged, problems such as partial loss of the image due to the enlargement of the entire image or a black band portion can be solved, and the screen can be reduced. An image that matches the aspect ratio can be obtained. As a result, burn-in can be prevented.

Moreover, in each case, it can be realized with a small circuit scale.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration in an already proposed example.

FIG. 3 is an explanatory diagram for explaining an operation content and a principle of image enlargement in the circuit of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a vertical enlargement control circuit of FIG. 1;

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is a block diagram showing another embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a vertical enlargement control circuit according to still another embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a usage example of the embodiment in FIG. 7;

FIG. 9 is a block diagram showing still another embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a usage example of the embodiment in FIG. 10;

[Explanation of symbols]

103 ... field memory, 104 ... vertical interpolation enlargement circuit, 105 ... one line memory, 106 ... vertical interpolation circuit,
107: horizontal interpolation enlargement circuit, 108: pixel delay circuit, 1
09 ... horizontal interpolation circuit, 110 ... vertical enlargement control circuit, 11
1. Memory control circuit 112. Vertical interpolation coefficient generation circuit
113 ... horizontal enlargement control circuit, 114 ... pixel delay control circuit, 115 ... horizontal interpolation coefficient generation circuit, 116, 117 ...
Delay circuit, 120: input terminal for vertical magnification setting value, 12
Reference numeral 1 denotes an input terminal of a horizontal enlargement ratio setting value, 122 denotes a memory control signal synthesizing circuit, 402 denotes an output terminal of an interpolation coefficient, 403.
... Output terminal of the memory control signal, 405.
6, 408 ... latch circuit, 501, 502 ... delay circuit,
601: horizontal enlargement control circuit, 701: counter, 702
Numeral converter, 903 video signal processing circuit, 904 synchronization processing circuit, 905 mode setting circuit, 906 vertical deflection circuit, 907 horizontal deflection circuit, 908, 909 deflection current correction circuit, 910 high voltage circuit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeru Hirata 4-6-6 Kanda Surugadai, Chiyoda-ku, Tokyo Inside Hitachi, Ltd. (72) Inventor Toshinori Murata 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Co., Ltd. Inside Hitachi Video Media Research Laboratory (72) Inventor Haruki Takada 292 Yoshidacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi Video Media Research Laboratories (72) Shinobu Torigoe 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Stock Inside Hitachi, Ltd.Video Media Research Laboratories (72) Inventor Takanori Eda 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd. Video Media Research Laboratories (72) Koichi Ishibashi 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Address Co., Ltd. Hitachi Image Information System

Claims (4)

[Claims] 1. A video compression / expansion device for converting an input video signal into a compressed or expanded video signal, a memory means for storing the input video signal, and a compression / expansion of the input video signal in a horizontal direction. Horizontal compression / expansion means; vertical compression / expansion means for compressing / expanding the input video signal in the vertical direction; screen position specifying means for specifying a position where the input video signal should be originally displayed; Video compression characterized by having a compression / expansion rate setting means for specifying a compression / expansion ratio for each screen position to be displayed, and enabling a different compression rate or expansion rate to be specified at each display position of a projected image. Magnifying device. 2. The video compression / expansion apparatus according to claim 1, wherein said screen position designation means is a counter means. 3. The apparatus according to claim 1, wherein said compression / expansion ratio setting means performs a specific arithmetic processing on an output signal of said screen position specifying means, and specifies a compression or expansion ratio. 3. The video compression / expansion device according to 1. 4. The video compression / expansion device according to claim 1, further comprising display means for displaying the video signal after conversion.