JPH09298701A - Device and method for displaying image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent malfunction in the case of pseudo letter box video input by generating a control signal for controlling the projecting state of a display means based on the continuous state of input video. SOLUTION: Assuming that the pseudo letter box image is inputted, since data showing the start and end positions of the image received from a video detection circuit 2 to a microcomputer 5, the aspect ratio of picture size is decided as '16:9' and therefore, it is operated to decrement a count value held by a 4:3 counter 511 holding values up to the moment. Since the 4:3 images are continuously inputted, even when there is the input of pseudo letter box video, the count value of the 4:3 counter 511 does not become '0' within a period shorter than the count value held in the 4:3 counter 511 so that the picture size can not be switched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device and an image display method, and more particularly to a display device having an aspect ratio of 16: 9, and an aspect ratio of 4: 3 or 16: 9.
The present invention relates to a video display device and a video display method most suitable for displaying a video signal having an aspect ratio of 9.

[0002]

2. Description of the Related Art Conventionally, as an image display device having a display element such as a horizontally long cathode ray tube having an aspect ratio of 16: 9 (hereinafter referred to as an aspect ratio), an image display device as shown in FIG. is there. FIG. 6 is an explanatory diagram for explaining the relationship between the display element and the image display state, in which 101 is a vertical synchronizing signal, 102 is a vertical deflection current, 103 is a horizontal synchronizing signal, and 104 is a horizontal deflection. Reference numeral 105 is a current, 105 is a display element having an aspect ratio of 16: 9, and 106 is a projection portion on the display element 105.

A video signal created on the assumption that it is displayed on a display device having an aspect ratio of 4: 3 (that is, by displaying on a display device having an aspect ratio of 4: 3, A video signal that allows a net video to be viewed without modification such as changing the aspect ratio.
It is called a video. ) Is received and 1 as shown in FIG.
The display state when projected on a display element 105 having an aspect ratio of 6: 9 and when projected on a display element which is 4: 3 is displayed as black bands at the upper and lower parts of the screen. The video signal of a so-called letterbox size video signal having an aspect ratio of 16: 9 (hereinafter,
It is called a letterbox image. ) Is received, and FIG.
An image display device capable of changing the projected screen size is commercialized, depending on whether it is projected on the display element 105 having an aspect ratio of 16: 9 as shown in FIG.

For example, when a 4: 3 image is displayed on the display element 105, a deflection current as shown in FIG. 6A is flown through a deflection yoke (not shown) to be displayed. On the other hand, when displaying a letterbox image,
For the displayable area of the display element as shown in (b),
The horizontal deflection current 104 and the vertical deflection current 102 are caused to flow through the deflection yoke based on the timing such that the time widths of the horizontal synchronization signal 103 and the vertical synchronization signal 101 both greatly exceed, and the original horizontal width and vertical width of the video signal are expanded. Then, the net image portion is displayed on the display unit 106 on the display element 105.

Therefore, the input video signal is 4:
Automatically detect 3 images or letterbox images,
In recent years, a technique for switching the screen size displayed based on the detection result has been proposed. FIG. 7 is a block diagram showing a conventional video display device. In the figure, 1 is a video signal input terminal, 2 is a detection circuit of a video portion of a video signal, 3 is a screen size switching circuit capable of switching the screen size by controlling a current flowing through a deflection yoke (not shown), Reference numeral 4 denotes a microcomputer, which controls the screen size switching circuit 3 according to a flow chart shown in FIG. 8 described later.

FIG. 8 is a flow chart for explaining the switching of the screen size used in the conventional video display apparatus. In the figure, S1 is a step of fetching video start position and end position data (capturing of video width). ), S
2 is a step for processing the captured video width data, S3
Is a step of determining whether the image width is 16: 9, S4 is a step of switching the screen size to 16: 9, and S5 is a step of switching the screen size to 4: 3.

Next, the operation will be described. A video signal of either a letterbox video or a 4: 3 video is input from the video signal input terminal 1. The image detection circuit 2 is
The number of horizontal scanning lines is counted starting from the vertical synchronizing signal 1 shown in FIG. 6, and the specified video level is 0 (hereinafter, referred to as 0IRE).
Called. Specified video level IRE: Institute
The video start position is the time when a video signal having a scanning line on which signals of at least radio signals are superposed is input, and the video signal having a scanning line at which a signal of 0 IRE or more is not superposed is input again. The time is regarded as the end position of the image, and the start position and the end position of the image are detected.

Digital data representing the start position and end position of the video detected by the video detection circuit 2 is input to the microcomputer 4. The microcomputer 4 takes in the video start position data and the video end position data transmitted from the video detection circuit 2 in step S1 of FIG.

Further, in steps S2 and S3, a storage area of the microcomputer 4 is stored in advance (this storage area does not need to be built in the microcomputer 4, and a storage element provided outside the microcomputer 4 is used. Is also good).
The image start position and end position data of the letterbox size image signal are compared, and if the image start position and end position data corresponding to the stored display size match, the process proceeds to step S4 to control the screen size switching circuit 3. Then, the screen size displayed is changed so as to correspond to the aspect ratio of 16: 9.

If the image start position and end position data corresponding to the stored display size do not match, the process proceeds to step S5, and the projected screen size is switched to correspond to the 4: 3 aspect ratio.

[0011]

The conventional image display device has the above-described structure, the net image signal corresponds to the aspect ratio of 4: 3, and the black portions are formed on the upper and lower portions. When an existing 4: 3 video (hereinafter referred to as a pseudo letterbox video) is input, this pseudo letterbox video is judged as a letterbox video, and the screen size is switched to 16: 9. There was a problem with the malfunction. The present invention has been made to solve the above problems, and an object of the present invention is to provide an image display device that does not malfunction when a pseudo letterbox image is input.

[0012]

In the video display device according to the first invention, the type of the input video is determined based on the display means for displaying the input video and the start position and the end position of the input video. And a continuous type output means for outputting a determination signal for outputting a determination signal, an output corresponding to the continuous state of the input image based on the determination signal from the image type determination means, and an output of the continuous state output means. And a control signal generating means for generating a control signal for controlling the projected state of the display means based on the above.

According to a second aspect of the present invention, in the image display apparatus according to the first aspect, the control signal generating means outputs the control signal based on the duration of the input video signal having an aspect ratio of 4: 3. It is configured to output.

In the image display device according to the third invention, in the image display device according to the first invention, the control signal generating means outputs the control signal based on the duration of the input image signal having an aspect ratio of 16: 9. It is configured to output.

According to a fourth aspect of the present invention, there is provided the image display device according to any one of the first to third aspects, wherein the control signal generating means controls the duration of the input video signal having an aspect ratio of 4: 3. The control signal is output based on the result of comparison with the duration of the input video signal having the aspect ratio of 16: 9.

According to a fifth aspect of the present invention, in the image display apparatus according to any one of the first to fourth aspects, the control signal generating means has a duration of an input video signal having an aspect ratio of 4: 3 or The control signal is output based on the result of comparison between the duration of at least one of the input video signals having an aspect ratio of 16: 9 and a predetermined upper limit value.

In the video display method according to the sixth aspect of the invention, the type of the input video is discriminated based on the start position and the end position of the input video, and the input continuation state of the input video is dealt with based on the discrimination result. A signal is output and the projection state is controlled based on the continuous state output of the input video.

In the image display method according to the seventh invention, in the image display method according to the sixth invention, the projection state is controlled based on the duration of the input image signal having an aspect ratio of 4: 3. I chose

In the video display method according to the eighth aspect of the present invention, the projection state is controlled based on the duration of the input video signal having the aspect ratio of 16: 9 in the video display method according to the sixth aspect of the invention. I chose

A video display method according to a ninth invention is the video display method according to any one of the sixth to eighth inventions, wherein the duration of the input video signal having an aspect ratio of 4: 3 and the aspect ratio of 16: 9. The projection state is controlled based on the result of comparison with the input video signal duration.

A video display method according to a tenth invention is the video display method according to any one of the sixth to ninth inventions, wherein the duration of the input video signal having an aspect ratio of 4: 3 or the aspect ratio of 16: 9. The projection state is controlled based on the result of comparison between the duration of at least one of the input video signals and a predetermined upper limit value.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION A video display device according to the present invention will be specifically described below with reference to the drawings showing an embodiment thereof. In the drawings, the same reference numerals indicate the same or corresponding ones as those in the related art.

Embodiment 1 1 is a block diagram showing an embodiment of a video display device according to the present invention. In the figure, 1 is a video signal input terminal, 2 is a type of a video signal input from a video signal input terminal 1 (at least 4). : 3
A screen size detection circuit 3 for a video signal as a video type determination means for determining a video or a letterbox video) controls the current flowing through the deflection yoke to switch the screen size (switch the projection state on the display means). A screen size switching circuit, 50 is a pre-judgment unit for judging whether or not the aspect ratio of the input video is a letterbox video based on the discrimination result (discrimination signal output) from the screen size detection circuit 2, and 51 is Based on the output of the pre-judgment unit 50, a measuring unit (hereinafter referred to as a counter unit) as a continuous state output unit for measuring (measuring) the duration (period) of the video signal input of at least 4: 3 video or letterbox video. 51)), 52 is a determination unit for determining the projected size of the display element based on the output of the counter unit 51, and 53 is a display element. The control signal generator 5 as a control signal generator that generates a control signal for controlling the projection size is a microcomputer, and at least the front determination unit 50, the counter unit 51, the determination unit 52, and the control signal generation unit 53. Each configuration (the part or function to be processed)
The screen size switching circuit 3 is controlled according to a flow chart shown in FIG. In the following description, the counter unit 511 (hereinafter, 4: 3 counter 511) for the counter unit 51 to obtain the duration of the 4: 3 video.
Called. ) Will be described.

In the following description, an example in which a cathode ray tube is used as a (image) display element as a display means for displaying an input image will be described. Examples of the display element include a liquid crystal display element and a plasma display element. Needless to say, a screen size switching circuit 3 may be used when a display element other than a cathode ray tube is used.
May use a drive device according to the type of display element used.

The ratio of occurrence of pseudo letterbox video in a normal broadcast signal is small. Therefore, the rate at which the pseudo letterbox image is erroneously determined to be the letterbox image is shorter than the time during which the 4: 3 image whose aspect ratio is determined to be 4: 3 is input. Therefore, in the description of the present embodiment, the case where the projection state on the display element is changed (switched) will be described by paying attention to the duration of the 4: 3 video and the pseudo letterbox video in the broadcast signal.

Next, the operation will be described with reference to the flowchart shown in FIG. In FIG. 2, S1
Is a step of capturing video start position and end position data (capturing of video width data), and S2 is that the start position and end position of the video signal are the video signal from the video start position and end position data captured in step S1, respectively. A step of processing the captured video width data, such as determining what number of scan lines in the scan line, or how many scan lines the input video signal has,
S3 is a step for determining the type of the input image (signal) for determining whether the image width is 16: 9 (letterbox image), and S4 is the screen size (projection state on the display element) is 16: 9. To switch the screen size (projection state on the display element) to 4: 3, and S6 to increase (increment) the count value (count value) of the 4: 3 counter 511 by 1, for example. S7 is a step of decreasing (decrementing) the count value (count value) of the 4: 3 counter 511 by 1, for example, and S8 is a step of determining whether or not the count value of the 4: 3 counter 511 is "0". .

The above steps S1 to S3 are performed by the pre-determining section 50, steps S6 and S7 are performed by the counter section 51, step S8 is performed by the determining section 52, and step S is performed.
4 and step S5, the control signal generator 53 operates according to each processing step. Also,
The series of operation steps from start to RTN (return) described below in the flowchart shown in FIG. 2 returns to start after one cycle, and constitutes an infinite loop (endless loop) such that the program is executed from step S1. It is configured to perform processing at 16 ms per loop.

The processing time of 16 mS per loop here is selected to be the same time length as the period of the vertical synchronizing signal of the NTSC signal. When the processing time per loop is set in this way, the processing of the program and the phase alignment of the vertical synchronizing signal are easy, and the microcomputer 5 once per loop starts the video detection position of the video detection circuit 2. Since it can be configured to receive the data of the end position and the end position, the flow of processing of the entire device can be controlled without complicating, and the device design can be easily performed. Of course, when handling video signals other than NTSC signals, NT
It suffices to set a period (1 field period, 1 frame period) in which a signal forming one screen corresponding to the vertical synchronizing signal of the SC signal is generated.

A video signal of either a letterbox video or a 4: 3 video is input from the video signal input terminal 1. The video detection circuit 2 counts the number of horizontal scanning lines starting from the vertical synchronization signal 1 shown in FIG. 6 and starts the video when there is an input of a video signal having a scanning line in which signals of 0IRE or more are superposed. The start position and the end position of the image are respectively detected as the end position of the image when there is a video signal input having a scanning line in which a signal of 0 IRE or more is no longer superimposed.

Digital data representing the start position and end position of the video detected by the video detection circuit 2 is input to the microcomputer 5. The microcomputer 5 takes in the video start position data and the video end position data transmitted from the video detection circuit 2 in step S1 of FIG.

Further, in steps S2 and S3, the storage area of the microcomputer 5 is stored in advance (this storage area does not need to be built in the microcomputer 5, and a storage element provided outside the microcomputer 5 is used. The image start position and end position data of the letterbox size video signal stored in (4.

If it is not determined to be a letterbox image in step S3, the process proceeds to step S6, the count value of the 4: 3 counter 511 up to that point is incremented, and the process proceeds to step S5. In step S5, the screen size switching circuit 3 is controlled so that the screen size corresponds to 4: 3 video.

If it is determined in step S3 that the image is a letterbox image, the process proceeds to step S7, and the 4: 3 counter 51 is used.
The count value up to that point of 1 is decremented, and in step S8, the count value of the 4: 3 counter 511 is
When it coincides with "0", the process proceeds to step S4 so that the screen size corresponds to 16: 9. If the count value of the 4: 3 counter 511 does not match “0”, the program for one loop is terminated and the process returns to step S1 to wait for the next data transmitted from the video detection circuit 2 ( stand by. After that, when the data of the start position and the end position of the video is transmitted from the video signal detection circuit 2, the operation for one loop is repeated from step S1.

The screen size currently displayed is 4: 3.
If the input video signal is in the state corresponding to the video and the input video signal is 4: 3 video, the data of the start position and the end position of the video received by the microcomputer 5 from the video detection circuit 2 has a screen size of 4: 3 video. Since the data is the data indicating the corresponding state, it is determined in step S3 that the aspect ratio is "not 16: 9", and 4:
The count value of the 3 counter 511 up to that point is incremented. That is, as long as 4: 3 video is continuously input, the 4: 3 counter 511 is incremented for one loop. Therefore, the 4: 3 counter 511 can increase the time during which 4: 3 video is continuously input. It is being measured.

Here, if a pseudo letterbox image is input, as described above, in step S3,
Since it is determined that the aspect ratio is “16: 9”, the process proceeds to step S7. In step S7, it operates so as to decrement the count value held in the 4: 3 counter 511 which holds the value up to that point. In the determination in step S8, since the 4: 3 video is continuously input until then, even if the pseudo letterbox video is input, if the period is shorter than the count value held in the 4: 3 counter 511. 4: 3 counter 5
Since the count value of 11 does not become "0", the screen size does not switch.

That is, since the 4: 3 video is continuously input, the count value held by the 4: 3 counter 511 indicates “the time when the 4: 3 video is input ÷ 16 mS”, which is 4: 3. When video is continuously input, it is basically determined to be 4: 3 video, but even if a video signal that is erroneously determined to be letterbox video, such as pseudo letterbox video, is input, At that point, the screen size does not switch to a letterbox image. Therefore, the duration determined to be 16: 9 is the predetermined time (4: 3 input until then).
If the video duration is not exceeded, the screen size switching is stabilized and the viewer is not annoyed by the frequent screen size switching.

Embodiment 2 In the above description of the first embodiment, the case where the 4: 3 counter 511 is provided and the duration of the 4: 3 video is measured has been described.
Switching of the screen size when playing back a TR, a video disc player, or the like will be described. When the playback operation of the video disc player or the like is paused (when the playback screen is not displayed, etc.), a full-blue signal or the like may be inserted. When playing such a video disc player, etc., when the original video signal is temporarily interrupted, such as when the letterbox video is paused, the video signal is temporarily interrupted, such as when paused. By the time, the 4: 3 image of full blue is input,
The counting operation of the 4: 3 counter 511 is performed, and 4: 3
The video counter may retain a count value larger than "0", and the screen size may not be immediately switched to the letterbox video.

In the description of this embodiment, 16:
The count value of the 9 counter 512 corresponds to the duration of the letterbox image. Therefore, it is intended to perform better switching by measuring both the time during which the 4: 3 video is continuously input and the time during which the letterbox video is continuously input.

In such a case, in the counter section 51, a 16: 9 counter 512 is provided in addition to the 4: 3 counter 511, and the duration of the video signal having the aspect ratio of each of the 4: 3 video and the letterbox video is provided. It is conceivable that the screen size is switched based on the result of comparison between the respective durations, and specifically, the flowchart for operating the microcomputer 5 is operated based on the flowchart shown in FIG. 3, for example. Let Hereinafter, description will be given with reference to the flowchart shown in FIG.

In FIG. 3, S1 is a step of capturing the image start position and end position data (capturing the image width), S2 is a step of processing the captured image width data, and S3 is an image aspect ratio of 16: 9. Step S4 is for determining whether or not the aspect ratio of the image displayed on the display element is changed to 16: 9, S4
5 is the aspect ratio of the image displayed on the display element is 4: 3
Switch to step S8, step S8 determines whether the count value of the 4: 3 counter 511 matches "0", step S9 decrements the count value of the 16: 9 counter 512, and counts the 4: 3 counter 511. Step of incrementing the value, S10 increments the count value of the 16: 9 counter 512, and 4:
The step of decrementing the count value of the 3 counter 511, S11 is a step of determining whether or not the count value of the 16: 9 counter 512 matches "0".

Next, the operation will be described. A video signal of either a letterbox video or a 4: 3 video is input from the video signal input terminal 1. The image detection circuit 2 is
The number of horizontal scanning lines is counted starting from the vertical synchronization signal 1 shown in FIG. 6, and when there is an input of a video signal having a scanning line on which signals of 0 IRE or more are superposed, the video start position is set again, and 0 IRE or more The start position and the end position of the image are respectively detected with the end position of the image when the input of the image signal having the scanning line in which the signal No.

Digital data representing the start position and end position of the video detected by the video detection circuit 2 is input to the microcomputer 5. The microcomputer 5 takes in the video start position data and the video end position data transmitted from the video detection circuit 2 in step S1 of FIG.

Further, in steps S2 and S3, the storage area of the microcomputer 5 is stored in advance (this storage area does not have to be built in the microcomputer 5, and a storage element provided outside the microcomputer 5 is used. The image start position and end position data of the letterbox size video signal stored in (4.

If it is determined in step S3 that the image is 4: 3, the process proceeds to step S9 and the 16: 9 counter 51 is used.
The count value of 2 is decremented, and the count value of the 4: 3 counter 511 is incremented. After that, if the count value of the 16: 9 counter 512 coincides with "0" in step S11, the process moves to step S5 and the aspect ratio of the image on the display element is switched to correspond to 4: 3 video. If the count value of the 16: 9 counter 512 does not match "0" in step S11, the program for one loop is terminated, and waits until the next video start position and end position data of the video width detection circuit 2 is input. To do.

On the other hand, if it is determined in step S3 that the signal is a letterbox signal, the process proceeds to step S10.
The count value of the 6: 9 counter 512 is incremented, and the count value of the 4: 3 counter 511 is decremented. After that, if the count value of the 4: 3 counter 511 coincides with "0" in step S8, the aspect ratio of the image of the display element is 16: 16 in step S4.
The program is switched so as to correspond to 9 images, the program for one loop is finished, and the program waits until the next image start position and end position data of the image width detection circuit 2 is input.

Normally, the time during which the pause or the like is performed is shorter than the time during which the reproduction is performed. Therefore, according to the above configuration,
By measuring the duration of the letterbox image, the aspect ratio of the screen of the display element does not switch to correspond to the 4: 3 image even if it is paused. You can enjoy the playback screen of.

Embodiment 3 In the above description of the embodiments, if either the letterbox video or the 4: 3 video is continuously watched (watched) for a long time, even if the video signal is switched, the 16: 9 counter 512 or 4 is displayed. : Since the count value of the 3 counter 511 is held, it is conceivable that the screen size does not switch for the time period that the user continued to watch before. In such a case, the microcomputer 5 is operated based on the flowchart shown in FIG. 4, for example.

In FIG. 4, S1 is a step of capturing the image start position and end position data (capturing the image width), S2 is a step of processing the captured image width data, and S3 is the image width of 16: 9 (letterbox image). ) Is determined, S4 is a step of switching the screen size to 16: 9, S5 is a step of switching the screen size to 4: 3, and S8 is a 4: 3 counter 5
11 is a step of determining whether the count value is equal to "0", S9 is a step of decrementing the count value of the 16: 9 counter 512, and incrementing the count value of the 4: 3 counter 511, S10 is 16:
Incrementing the count value of the 9 counter 512 and decrementing the count value of the 4: 3 counter 511; S11 is a step of determining whether the count value of the 16: 9 counter 512 matches "0";
S12 is a step of determining whether or not the count value of the 16: 9 counter 512 matches the preset upper limit value, and S13 is whether the count value of the 4: 3 counter 511 matches the preset upper limit value. This is the step of determining whether or not.

Next, the operation will be described. A video signal of either a letterbox video or a 4: 3 video is input from the video signal input terminal 1. The image detection circuit 2 is
The number of horizontal scanning lines is counted starting from the vertical synchronization signal 1 shown in FIG. 6, and when there is an input of a video signal having a scanning line on which signals of 0 IRE or more are superposed, the video start position is set again, and 0 IRE or more The start position and the end position of the image are respectively detected with the end position of the image when the input of the image signal having the scanning line in which the signal No.

Digital data representing the start position and end position of the video detected by the video detection circuit 2 is input to the microcomputer 5. The microcomputer 5 fetches the image start position data and the image end position data transmitted from the image detection circuit 2 in step S1 of FIG.

Further, in steps S2 and S3, the storage area of the microcomputer 5 is stored in advance (this storage area does not need to be built in the microcomputer 5 and a storage element provided outside the microcomputer 5 is used. Is also good).
Compare with the video start position and end position data of the letterbox size video signal. If the image start position and end position data corresponding to the stored display size match, the process proceeds to step S12, and if they do not match, the process proceeds to step S13.

In step S12, it is determined whether the count value of the 16: 9 counter 512 matches the upper limit value, and in step S13, the count value of the 4: 3 counter 511 matches the upper limit value. .
16: 9 counter 512 or 4: 3 counter 511
If the count value of any one of the counters matches the upper limit value, the program for one loop is ended, the next input data from the video detection circuit 2 is waited, and the 4: 3 counter 511 or 16: The counting operation of each of the nine counters 512 is temporarily stopped. Accordingly, the screen size is switched if the upper limit time elapses at the longest after the video signal is switched.

When determining the upper limit value, the ratio of the pseudo letterbox image to the entire 4: 3 image in terms of time, or following the letterbox signal (laser disk player, etc.) It may be determined in consideration of how much a 4: 3 image such as full-screen blue is input in terms of time.

For example, 3 minutes may be set in advance in consideration of the switching time from the first surface to the second surface of the disk of the laser disk player, the time of a commercial broadcast during normal television broadcasting, and the like. Alternatively, the viewer side may be configured to set an arbitrary time.

Embodiment 4 The microcomputer 5 is operated based on the flowchart shown in FIG. 5, for example. In the above description of the third embodiment, the 16: 9 counter 5 is used in steps S11 and S8.
Although it is configured such that the count value of each of the 12 and 4: 3 counters 511 is compared and determined with "0", step S1
16: 9 counter 51 instead of 1 and step S8
Step S15 (determining whether the count value of the 16: 9 counter 512 is equal to or greater than the count value of the 4: 3 counter 511) or step S14 (determining whether the count value of the 4: 3 counter 511 is greater than the count value of the 4: 3 counter 511) is performed. An example in which (count value ≧ 16: 9 counter 512 count value determination) is provided will be described below.

Next, the operation will be described. A video signal of either a letterbox video or a 4: 3 video is input from the video signal input terminal 1. The image detection circuit 2 is
The number of horizontal scanning lines is counted starting from the vertical synchronization signal 1 shown in FIG. 6, and when there is an input of a video signal having a scanning line on which signals of 0 IRE or more are superposed, the video start position is set again, and 0 IRE or more The start position and the end position of the image are respectively detected with the end position of the image when the input of the image signal having the scanning line in which the signal No.

Digital data representing the start position and end position of the video detected by the video detection circuit 2 is input to the microcomputer 5. The microcomputer 5 fetches the image start position data and the image end position data transmitted from the image detection circuit 2 in step S1 of FIG.

Further, in steps S2 and S3, the storage area of the microcomputer 5 is stored in advance (this storage area does not need to be built in the microcomputer 5, and a storage element provided outside the microcomputer 5 is used. The image start position and end position data of the letterbox size image signal stored in step S12 are compared with the image start position and end position data corresponding to the stored display size. Proceed to step S1 if they do not match
Move to 3.

4: 3 4: 3 of the time when an image is input
The count value of the counter 511 and the 16: 9 counter 512
Is compared with the count value in step S14 and step S15. That is, when it is determined that the ratio is 16: 9 in step S3, the process proceeds to step S12 and the 16: 9 counter 51
If 2 is not the upper limit value, the process proceeds to step S10, and the values of the 4: 3 counter 511 and the 16: 9 counter 512 are compared in step S14.

Here, when the pseudo letterbox image is input when the 4: 3 image is continuously input, since the count value of the 4: 3 counter 511 is larger, the image of the display element is Do not switch the aspect ratio to 16: 9. However, the letterbox image continues to be input,
If the time during which the letterbox image continues to be input is longer than the time during which the 4: 3 image is input, the aspect ratio of the image on the display device is switched to 16: 9. On the other hand, it is 4: 3 than the time when the letterbox image is input.
If the time during which the image is continuously input becomes longer, the aspect ratio of the image on the display element is switched to 4: 3.
Therefore, since the microcomputer 5 determines the state (duration) of the input video signal, the screen size can be selected according to the input video signal, and the screen size of the viewer can be changed frequently. Discomfort caused by switching can be reduced.

When the video signal is intentionally switched, the 16: 9 counter 512 or the 4: 3 counter 5 is used.
Initialization is performed by setting the count value of 11 to "0", and it is possible to determine the screen size and switch the screen size by eliminating the influence of the video signal input before switching the screen size. .

The image display state may be switched by combining at least two of the configurations of the first to fourth embodiments described above, and the configuration is not necessarily limited to the configurations described in the first to fourth embodiments. is not.

[0063]

Since the present invention is constructed as described above, it has the following effects.

In the video display apparatus according to the present invention, the display means for displaying the input video and the type of the input video are discriminated based on the start position and the end position of the input video to output the discrimination signal. Of the video type discriminating means, the continuous state output means for performing an output corresponding to the continuous state of the input video based on the discrimination signal from the video type discriminating means, and the display of the display means based on the output of the continuous state outputting means. Since the control signal generating means for generating a control signal for controlling the state is provided, it is possible to obtain an image display device which does not malfunction when a pseudo letterbox image is input, for example.

Further, in the video display device according to the present invention, the control signal generating means is designed to output the control signal based on the duration of the input video signal having the aspect ratio of 4: 3. A video display device that does not erroneously switch to a projection state corresponding to a letterbox video when an image is input, and does not give a viewer an uncomfortable feeling due to frequent switching of the projection state Can be provided.

Further, in the video display device according to the present invention, the control signal generating means is designed to output the control signal based on the duration of the input video signal having the aspect ratio of 16: 9, so that the letterbox video is particularly preferable. Even if a 4: 3 image is temporarily input during continuous viewing, it is possible to continuously display a letterbox image. It is possible to provide a video display device that does not give discomfort due to switching.

Further, in the video display device according to the present invention, the control signal generating means compares the comparison result between the duration of the input video signal having the aspect ratio of 4: 3 and the duration of the input video signal having the aspect ratio of 16: 9. Since it is configured to output the control signal based on the original, it is possible to switch the projection state in consideration of the projection state of the image that the viewer has been watching until then, and display according to the viewer's preference. It is possible to provide a video display device that can realize the state.

Further, in the video display device according to the present invention, the control signal generating means causes the duration of the input video signal having the aspect ratio of 4: 3 or the duration of the input video signal having at least one of the aspect ratio of 16: 9. Since the control signal is output based on the result of comparison between the above and a predetermined upper limit value, even if either 4: 3 video or letterbox video is input for a relatively long time, 4: 3 video is input.
Switching from video to letterbox video or switching from letterbox video to 4: 3 video is ensured even after the maximum period has passed even at the longest, and the viewer feels uncomfortable due to frequent switching of the projection state. It is possible to provide a video display device that does not provide

In the video display method according to the present invention, the type of the input video is discriminated based on the start position and the end position of the input video, and the input continuation state of the input video is dealt with based on the discrimination result. Since the signal is output and the projection state is controlled based on the continuous state output of the input video,
For example, when a pseudo letterbox image is input, it is possible to realize image display without malfunction.

Further, in the image display method according to the present invention, since the projection state is controlled based on the duration of the input image signal having the aspect ratio of 4: 3, the pseudo letterbox image is input. In this case, there is no chance of accidentally switching to the projection state corresponding to letterbox video, especially during viewing of 4: 3 video according to the NTSC broadcasting system currently recognized as general television video. It is very effective, and it is possible to realize video display that does not give a viewer an unpleasant feeling due to frequent switching of the projection state.

Further, in the image display method according to the present invention, since the projection state is controlled based on the duration of the input image signal having the aspect ratio of 16: 9, the letterbox image is continuously displayed. If you are watching
Even if a 4: 3 image is temporarily input, the letterbox image can be displayed continuously. Therefore, when the letterbox image is being viewed especially in the so-called cinema mode, the letterbox image is temporarily displayed. Entered in 4:
Since the projection state is not immediately switched by the three images, it is possible to realize a video display that does not give the viewer an unpleasant feeling due to the frequent switching of the projection state.

Further, in the image display method according to the present invention, the image is displayed based on the result of comparison between the duration of the input image signal having the aspect ratio of 4: 3 and the duration of the input image signal having the aspect ratio of 16: 9. Since the state is controlled, it is possible to switch the projecting state in consideration of the projecting state of the image that the viewer was watching until then, so that the display state according to the taste of the viewer is realized. it can.

In the video display method according to the present invention, the duration of the input video signal having the aspect ratio of 4: 3 or the duration of the input video signal of at least one of the aspect ratio of 16: 9 and a predetermined upper limit value. Since the projection state is controlled based on the result of comparison with 4: 3,
Even if either video or letterbox video is input for a long time ratio, switching from 4: 3 video to letterbox video or switching from letterbox video to 4: 3 video is the maximum value even at the longest. It is possible to realize the image display which is surely performed after the lapse of the period and which does not give the viewer the discomfort caused by the frequent switching of the projection state.

[Brief description of drawings]

FIG. 1 is a block diagram of a video display device according to a first embodiment.

FIG. 2 is a flowchart for explaining switching of screen sizes used in the video display device according to the first embodiment.

FIG. 3 is a flowchart for explaining switching of screen sizes used in the video display device according to the second embodiment.

FIG. 4 is a flowchart for explaining switching of screen sizes used in the video display device according to the third embodiment.

FIG. 5 is a flowchart for explaining switching of screen sizes used in the video display device according to the fourth embodiment.

FIG. 6 is an explanatory diagram for explaining a relationship between a display element and a video display state in a conventional video display device.

FIG. 7 is a block diagram showing a conventional video display device.

FIG. 8 is a flowchart for explaining switching of screen sizes used in a conventional video display device.

[Explanation of symbols]

1 video signal input terminal, 2 video detection circuit, 3 screen size switching circuit, 5 microcomputer, 50 front determination section, 51 counter, 52 determination section, 53 control signal generation section, 511 4: 3 counter, 512 16: 9 counter .

Claims (10)

[Claims] 1. Display means for displaying an input image,
An image type determination unit for determining the type of the input image based on the start position and the end position of the input image and outputting a determination signal, and the input based on the determination signal from the image type determination unit A continuous state output means for performing an output corresponding to the continuous state of the image, and a control signal generation means for generating a control signal for controlling the projected state of the display means based on the output of the continuous state output means. A video display device characterized by the above. 2. The aspect ratio of the control signal generating means is 4: 3.
The video display device according to claim 1, wherein the control signal is output based on the duration of the input video signal. 3. The control signal generating means has an aspect ratio of 16:
The video display device according to claim 1, wherein the control signal is output based on the duration of the input video signal of 9. 4. The control signal generating means has an aspect ratio of 4: 3.
4. The control signal is output based on the result of comparison between the duration of the input video signal and the duration of the input video signal having an aspect ratio of 16: 9. The image display device described. 5. The control signal generating means has an aspect ratio of 4: 3.
Input video signal duration or aspect ratio 16: 9
The video according to any one of claims 1 to 4, wherein the control signal is output based on a comparison result between the duration of at least one of the input video signals and a predetermined upper limit value. Display device. 6. The type of the input video is discriminated based on the start position and the end position of the input video, and a signal corresponding to the input continuation state of the input video is output based on the discrimination result. A video display method characterized in that the projection state is controlled based on the continuous state output. 7. The video display method according to claim 6, wherein the projection state is controlled based on the duration of the input video signal having an aspect ratio of 4: 3. 8. The video display method according to claim 6, wherein the projection state is controlled based on the duration of the input video signal having an aspect ratio of 16: 9. 9. The projection state control is performed based on a result of comparison between a duration of an input video signal having an aspect ratio of 4: 3 and a duration of an input video signal having an aspect ratio of 16: 9. The video display method according to claim 6. 10. A projection based on a comparison result between a duration of an input video signal having an aspect ratio of 4: 3 or a duration of an input video signal having at least one of an aspect ratio of 16: 9 and a predetermined upper limit value. 10. The image display method according to claim 6, further comprising controlling the state.