JP2008011367A - Video signal switching apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signal switching apparatus capable of automatically selecting a video signal from a video apparatus whose operation mode is switched to a reproduction mode. <P>SOLUTION: In the video signal switching apparatus for switching and selecting one of three video signals A, B, C supplied from three video apparatus (not shown) to an input stage 1 by a signal selection part 6 and supplying the selected video signal to a video display apparatus, OSD data to be output when the video apparatus are switched to the reproduction mode are previously stored in an OSD data storing memory 3 in each video apparatus, a comparator 4 compares the signals A, B, C input from a memory part 2 with the OSD data input from the OSD data storing memory 3, and when the signal including the OSD data out of the signals A, B, C is detected, a comparison judgment circuit 5 supplies a control signal X for switching to the detected signal to the signal selection part 6 to automatically supply the signal to the video display apparatus. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a means for selecting an output image signal in a video selection device such as an image display device or AV selector having a plurality of video signal input terminals.

  In video equipment such as a television receiver and AV selector provided with a plurality of external input terminals, it is necessary to select the terminal into which the video to be captured is input from among the plurality of input terminals. In general, input terminal switching means is provided. For the switching at this time, a method in which the user (user) himself / herself switched by a toggle method (so-called circulation sequential feeding method), for example, using a remote controller or a switch was mainly used.

In recent years, with the aim of simplifying operations, manual operation is performed by detecting the presence or absence of plug connection to the input terminal and the presence or absence of a signal appearing at the input terminal, and selecting and switching the input terminal where the signal appears. Regardless of this, video equipment that can automatically switch input terminals has been proposed as a prior art (see, for example, Patent Documents 1 and 2). At this time, in the case of the prior art based on the presence / absence detection of the signal, it is common to detect and switch the synchronization signal included in the video signal.
Japanese Patent Application No. 2001-8115 Japanese Patent Application No. 2000-59703

  The above prior art does not assume a case where a signal is constantly input, and in this case, there is a problem that it cannot meet a user's request. In the case of the video signal switching device targeted by the present invention, as a device connected to the external input terminal, a device of a type having a built-in tuner so that a television broadcast can be received and recorded, such as a so-called video deck. In this case, as long as the power is on, a video signal is usually output to the output terminal even during a recording operation such as timer recording.

  On the other hand, in such a case, what the user desires is usually selection of a video signal reproduced from a recording medium by a device such as a video deck, but in the conventional technology, if a video signal is input anyway, The input terminal is merely selected, and therefore, the conventional technique causes a problem that it cannot meet the user's request.

  Further, in the prior art, it is not assumed that video signals are simultaneously input to a plurality of input terminals, and in this case, a plurality of input terminals are selected at the same time or none of them are selected, The switching result is indefinite, and there is a possibility that the process is not intended by the user, and the user's request cannot be satisfied.

  An object of the present invention is to provide a video signal switching device in which a video signal from a video device whose operation mode is a playback mode is automatically selected.

  Here, in the present invention, in a device such as a television receiver or an AV selector to which a plurality of devices are connected, the video that the user wants to watch is based on the video signal output from the device that has started playback. For this reason, OSD display patterns such as “playback” characters and special symbols appearing on the screen at the start of playback, instead of switching by the conventional synchronization signal and terminal connection detection. By detecting this, the input signal is automatically selected. Here, OSD is an abbreviation for on-screen display.

  At this time, the OSD display by the video equipment has a display pattern specific to each model. If the OSD display function is turned on, this OSD display is performed when processing such as playback is started. Appears on the screen for only a short time. Therefore, using this, the OSD display data and the information of the position to be displayed when processing such as reproduction is performed are registered in advance in the memory for each model, and compared with the video signal from each input terminal. The presence or absence of registered OSD data is confirmed. If there is an input signal in which the registered OSD is detected, it is determined that the user has performed processing such as playback on the device outputting this signal, and the output video to an external monitor or the like It is conceivable to perform selection and switching.

  By the way, in general, video equipment is accompanied by image disturbance at the start of reproduction. At this time, the superimposed OSD data is also affected, and the data shape, position, and the like change. For this reason, it is not practical to determine only an OSD that is completely matched. Therefore, in consideration of this determination error, it is conceivable to provide a fixed threshold value for comparison determination, and to provide a circuit for determining the reproduction state only when the numerical value is exceeded. There is also a possibility that there is a scene similar to that in this case, so that in this case as well, it is possible to limit the comparison determination target to image data before and after the synchronization at the start of reproduction is switched.

  Accordingly, the above object is to provide a video signal switching device that selects one type of video signal from among a plurality of video signals input from the outside and outputs the selected video signal to an external image display device. A means for detecting whether or not an OSD signal is included is provided, and when a video signal in which an OSD signal is detected appears among the plurality of video signals, the video signal is selected and the external image display device This is accomplished by outputting to

  At this time, even if a threshold value is set for determining whether an OSD signal is included in each of the plurality of video signals, the above object is achieved, and an OSD signal is provided for each of the plurality of video signals. The above object is achieved even if a means for limiting the image signal used for determining whether or not it is included to a signal based on frames before and after the period in which the synchronization of the signal becomes unstable is provided, Further, there may be provided means for limiting an image signal used for determining whether or not an OSD signal is included in each of the plurality of video signals to a signal by a specific portion of the screen based on the signal. The above objective is achieved.

  According to the present invention, even when a plurality of video devices connected to the apparatus are powered on or recording and outputting a video signal, if a video device in the playback mode appears, that video device only appears. The switching operation for selecting the signal is automatically performed. Therefore, when there is an image to be reproduced, the user simply performs the reproduction operation of the video equipment, and does not need to perform a signal switching operation, and can satisfy the user's request.

  Hereinafter, a video signal switching device according to the present invention will be described in detail with reference to embodiments shown in the drawings. Here, FIG. 1 is a block diagram showing an embodiment of the present invention. At this time, the entire video signal switching device is represented by 10. As shown in the figure, this is an input stage 1, an image memory unit 2, The memory includes an OSD data storage memory 3, a comparator 4, a comparison determination circuit 5, a signal selection unit 6, and a synchronization detector 7. At this time, it is assumed that, for example, three types of video signals of signal A, signal B, and signal C are individually input from three video devices such as a video deck.

  Here, first, the input stage 1 is a portion to which a signal from a video output device such as a video deck is input, which corresponds to a plurality of video input terminals of the video signal switching device 10, and the three types of video input here. Signals, that is, three types of video signals of signal A, signal B, and signal C are supplied in parallel to the image memory unit 2, the OSD data storage memory 3, the signal selection unit 6, and the synchronization detector 7, respectively. It has become. At this time, the image memory unit 2 is provided with three frame memories, a frame memory A, a frame memory B, and a frame memory C. When signals are input to the input stage 1, the input signals A and B are input. , C are stored individually in the frame memories A, B, C, respectively.

  At this time, the OSD data storage memory 3 stores the inputted OSD data for each device and its position data, and is registered in advance. Then, each video signal is input from the frame memories A, B, and C of the image memory 2 to the comparator 4, and OSD data corresponding to each device is input from the OSD data storage memory 3 together with the video signal. Therefore, the comparator 4 compares the input video signal with the OSD data for each line, and supplies the comparison result to the comparison determination circuit 5. Therefore, the comparison determination circuit 5 determines whether OSD display data exists in the video signal input at this time based on the input comparison result, and uses the determination result as a control signal X as a signal. This is supplied to the selector 6.

  Here, the signal selection unit 6 selects any one of the three types of signals A, B, and C supplied from the input stage 1, switches them to the outside, and outputs them to an image such as a television receiver. The signal switching control for this purpose is performed by the control signal X supplied from the above-described comparison / determination circuit 5 and, on the other hand, given from the user by a remote controller or the like. This is performed by the control signal Y. The last control signal has priority over the switching result at this time. That is, when the control signal X (or control signal Y) is input, the switching result by the control signal X (or control signal Y) is held until the control signal Y (or control signal X) is input thereafter. .

  At this time, the control signals X and Y have the same three types of switching modes corresponding to the three types of signals A, B and C, that is, the three types of switching modes of modes a, b and c. First, the comparison / determination circuit 5 sets the control signal X to the switching mode a when the OSD display data exists in the signal A, changes to the switching mode b in the case of the signal B, and the signal C. When switching to the switching mode c. On the other hand, the control signal Y is set to any one of the switching mode a, the switching mode b, and the switching mode c by the user, for example, by a toggle method. Therefore, the signal selection unit 6 selects the signal A when it is in the switching mode a, selects the signal B when it is in the switching mode b, and selects the signal B when it is in the switching mode c. Selects the signal C and outputs the selected video signal to an external device.

  By the way, in this signal switching device 10, a predetermined threshold th is set for determination in the comparison determination circuit 5 as shown in the figure. In addition, a synchronization detector 7 is provided here, and a synchronization detection signal G is output from this, and is input to the comparator 4 and the comparison determination circuit 6. These operational effects will be described in detail later. To do.

  Next, the operation of this embodiment will be described with reference to FIG. Here, FIG. 2 is a diagram for explaining how the data of the entire video including the OSD displayed when the video equipment performs a reproduction operation is represented. First, FIG. ) Shows a state in which the video equipment is turned on and the video received by the tuner is displayed. Here, for the sake of explanation, as an example, the center of the gray background is slightly below the background. The case of a simplified image with only bright hexagonal figures is shown.

  Next, FIG. 2 (b) shows an image immediately after the video device is set to the playback mode, and an OSD display appears on the screen at this time. There is no change and only the OSD display is superimposed on the image. The OSD display shape and the appearing position at this time differ depending on the type of the video equipment, but here, as a simple example for the sake of explanation, the word “play” is displayed in the upper right part of the screen, and below it. A case is shown in which a horizontal triangle is displayed as a symbol representing the playback mode.

  After that, since the reproduction mode is set, an image reproduced from the recording medium is output in place of the original image. Therefore, FIG. 2 (c) shows the image at this time, and as an example, the reproduced image at this time is an image in which a slightly bright oval figure is present in the central portion of the gray background. Simplified. At this time, although the OSD display also varies depending on the type of the video equipment, for example, it continues for about 30 seconds and then disappears. FIG. 2C shows a state where the OSD display still remains.

  Here, the image signal is composed of image data for each horizontal line shown as a scan line in FIG. Therefore, FIG. 2 (d) shows how the data of one line is at this time, and here, as an example, the luminance in the scan line marked with * in FIG. 2 (c) is shown. Although data is shown, in this case, as shown in the figure, there is a horizontal synchronization signal first, followed by a gray part that appears by the background part, while a part with high luminance by the elliptical figure part appears, When it comes to the gray part, the luminance decreases, the luminance increases at the OSD display, and finally returns to gray, thereby forming one line of data.

  The data obtained by collecting the data for each line on the entire screen is an image. When attention is paid to the OSD display portion, data of a predetermined luminance (color difference) level always appears at a predetermined position. Therefore, the entire screen is stored in each frame memory A, B, C of the image memory unit 6 and compared with the OSD data stored in the OSD data storage memory 3 in advance by the comparator 4 for each line. The comparison determination circuit 5 determines whether or not the OSD indicating the reproduction state is at the determined display position, and supplies the control signal X to the signal selection unit 6 to switch the selection of the signals A, B, and C. Is controlled.

  Therefore, according to this embodiment, when a video device set in the playback mode appears among the three video devices connected to the input stage 1, the image signal from the video device is simply sent to the signal selection unit 6 as it is. As a result, when there is an image that the user wants to see, the image that is the signal source of the image among the three video devices is selected. All you have to do is put the device in playback mode, and you will be able to fully enjoy its ease of use.

  Here, the threshold value th set in the comparison determination circuit 5 will be described.

  In the case of video equipment such as a video deck, under normal operating conditions, the image signal may be synchronized or the video may be disturbed due to the reception status or the tracking operation immediately after the start of playback. In this case, the OSD display part In the same way, the image is distorted and the display position is shifted. Then, in this case, since the comparison / decision circuit 5 cannot obtain complete data coincidence, there is a possibility that the practicality of the signal becomes poor, for example, the signal cannot be switched in spite of the reproduction mode. .

  Therefore, when the threshold value th is set in the comparison / determination circuit 5 and a match is obtained at the level of the threshold value th, the control signal X is generated so that the switching operation by the signal selection unit 6 can be obtained. According to this embodiment, a practical signal switching operation can be obtained. If the threshold value th at this time is too large, malfunctions are likely to occur. For example, the signal may be switched due to noise or the like even though the playback mode is not set. Will fall. Therefore, it goes without saying that it must be set experimentally to some extent.

  Next, the synchronization detector 7 will be described. The synchronization detector 7 receives signals A, B, and C, detects the synchronization state by each synchronization signal, and performs the comparison operation by the comparator 4 and the determination operation by the comparison determination circuit 5. It works only when the synchronization status changes. This is because, for example, if there is a video portion similar to the OSD data in the input image, such as a recorded video on a video playback screen, an erroneous determination may be made. This is based on the fact that when the video device is set to the playback mode and the original video is switched to the playback video, the synchronization signal is also switched, and the synchronization changes at this time.

  That is, when the video equipment is set to the playback mode and replaced with the video reproduced from the original video, the synchronization signal is also switched, and the synchronization varies. Therefore, this synchronization fluctuation is detected by the synchronization detector 7 to generate the synchronization detection signal G, and only when there is a synchronization fluctuation, that is, a signal by a frame before and after the period when the synchronization of the signal becomes unstable. The comparator 4 and the comparison determination circuit 6 are controlled by the synchronization detection signal G so that the data before and after the synchronization fluctuation is to be compared, and the OSD display discrimination is limited to before and after the synchronization fluctuation. Even if a video similar to the display is input, erroneous determination can be avoided.

  By the way, where the OSD data displayed at the time of reproduction is displayed on the screen is fixed for each video device. For example, in the example of FIG. Therefore, from this, the part to be compared in the screen can also be limited. Therefore, the comparison process in the comparator 4 may be performed only in a specific range (line) indicated by the position data stored in the OSD data storage memory 3. In this case, each frame memory of the image memory unit 2 can be reduced from a memory capacity for one frame to a memory size for several lines, which is advantageous in terms of cost.

It is a block block diagram which shows one Embodiment of the video signal switching apparatus by this invention. It is operation | movement explanatory drawing of one embodiment of this invention.

Explanation of symbols

1: Input stage 2: Image memory unit 3: Memory for storing OSD data 4: Comparator 5: Comparison determination circuit 6: Signal selection unit 7: Synchronization detector G: Synchronization detection signal X: Control signal (by comparison determination circuit 5) Control signal)
Y: Control signal (control signal by user)
th: Determination threshold

Claims (4)

In a video signal switching device that selects one type of video signal from a plurality of video signals input from the outside and outputs the selected video signal to an external image display device,
Means for detecting whether an OSD signal is included in each of the plurality of video signals;
Video signal switching characterized in that when a video signal in which an OSD signal is detected appears among the plurality of video signals, the video signal is selected and output to the external image display device apparatus. In the video signal switching device according to claim 1,
A video signal switching device, wherein a threshold value is set for determining whether an OSD signal is included in each of the plurality of video signals. In the video signal switching device according to claim 1,
Means are provided for limiting an image signal used for determining whether or not an OSD signal is included in each of the plurality of video signals to signals of frames before and after a period in which the synchronization of the signal becomes unstable. A video signal switching device characterized by comprising: In the video signal switching device according to claim 1,
An image characterized in that means for limiting an image signal used for determining whether or not an OSD signal is included in each of the plurality of image signals to a signal by a specific portion of the screen based on the signal is provided. Signal switching device.

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