JP2006140627A - Video signal processor and television image receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video signal processor and a television image receiver muting a disordered image generated by external equipment in proper timing. <P>SOLUTION: The video signal processor is constituted so that when a plurality of unit image signals constituting a moving picture video signal are inputted one after another and outputted one after another to a display means for video, it is decided whether each of the unit image signals needs to be muted according to a detection result of disorder of the unit image, display of the unit image signal is delayed by longer than a time needed to discriminate whether the signal needs to be muted, and the delayed unit image signal is properly muted according to the discrimination result of the necessity of the muting processing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a video signal processing apparatus for processing a video signal and a television receiver including the same, and in particular, a video signal processing apparatus for performing mute processing on a distorted video screen generated at the time of channel switching or the like. , And a television receiver including the same.

When the channel is switched by an input operation of a remote controller or the like, the image displayed by the display means of the television receiver may be temporarily disturbed. Such a disturbed image is visually uncomfortable. Therefore, the technique described in Patent Document 1 is known as maintaining visual comfort of a video output device (such as a television receiver) by preventing the display of a distorted image. .
Patent Document 1 discloses a broadcast receiving device that detects an input operation when a viewer performs a channel switching input operation and mutes an image of several frames displayed during the channel switching. Is disclosed.
JP 2003-333446 A

However, in the method shown in Patent Document 1, the television receiver is connected to an external device such as a video device (video playback / recording device), and the channel is switched by the external device. It is not effective in some cases. This is because when the television receiver performs channel switching control, the television receiver can determine when to mute an image based on the timing at which the television receiver performs switching control. On the other hand, when channel switching control is performed by an external device, it is impossible to determine the timing at which muting should be performed.
Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to perform video signal processing capable of performing mute processing at an appropriate timing even for a distorted image generated by an external device. It is to provide an apparatus and a television receiver.

In order to achieve the above object, the present invention detects a disturbance of a unit image when a plurality of unit image signals constituting a moving image signal are sequentially input and the unit image signal is sequentially output to a video display means. Based on the result, the necessity of the mute process is determined for each of the unit image signals, the display of each of the unit image signals is delayed for a predetermined time necessary for determining the necessity, and the determination result of the necessity of the mute process Accordingly, the apparatus is configured as a video signal processing apparatus that appropriately performs mute processing on the delayed unit image signal.
The time required for determining whether or not mute processing is necessary is a predetermined time that can be calculated in advance. Therefore, it has the function of detecting the disturbance of the image and the function of delaying the display of the unit image by the time necessary for determining whether or not the mute processing is necessary based on the detection result, thereby causing the disturbance caused by the external device. It is possible to mute the image signal at an appropriate timing to prevent display of the disordered image.

Here, when disturbance is continuously detected for a plurality of unit image signals that are sequentially input, it may be determined that mute processing is necessary for the plurality of unit image signals that are consecutive.
Actually, it seems that the disordered image is visually uncomfortable when the disordered image is continuously displayed. Therefore, according to the above configuration, the mute process is performed reliably and without waste only when the viewer actually feels uncomfortable.
Further, the determination of whether or not the image by the unit image signal is disturbed, which is used for determining whether or not mute processing is necessary, is performed by using a signal corresponding to a vertical synchronization signal or a horizontal synchronization signal corresponding to the moving image signal. It can be done based on the signal or both.
For example, when the unit image is disturbed, for example, when the channel is switched, the number of horizontal synchronization signals included in one unit image signal is larger than a predetermined number (for example, 525) in the normal state. It is known to decrease. In addition, it is known that the period of the vertical synchronizing signal that divides each unit image signal is shortened. As described above, when the signal corresponding to the vertical synchronizing signal and the signal corresponding to the horizontal synchronizing signal are used, it is possible to reliably detect the disturbance of the unit image by a quantitative method.

  According to the present invention, the main body has a function of detecting the disturbance of the image and a function of delaying the display of the unit image by a time necessary to determine whether or not mute processing is necessary based on the detection result. Regardless of the channel switching by the device, it is possible to perform a mute process at an appropriate timing for a disturbed image signal generated by an external device, thereby preventing display of the disturbed image.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
Here, FIG. 1 is a conceptual diagram for explaining the function of the video signal processing apparatus according to the present invention, FIG. 2 is a schematic configuration diagram of the television receiver X according to the embodiment of the present invention, and FIG. FIG. 4 is a conceptual diagram showing the operation of the synchronization signal separation circuit 5 included in the television receiver X according to the embodiment of the present invention, and FIG. 4 is a block diagram showing a schematic configuration of the non-standard determination circuit 7. FIG. 5 is a flowchart showing a processing procedure for determining whether or not the unit image signal is non-standard by using the horizontal synchronizing signal or the vertical synchronizing signal by the video signal processing apparatus A according to the embodiment of the present invention. It is a flowchart which shows the process sequence by the video signal processing apparatus A which concerns on embodiment of this invention from the start of the mute process based on determination whether a unit image signal is nonstandard, and cancellation | release of a mute process.

(1) Outline of video signal processing apparatus according to the present invention The video signal processing apparatus according to the present invention is configured such that a plurality of unit image signals representing an image for one frame, which basically constitutes a video image signal, are sequentially input. When the unit image signal is displayed on a video output unit (an example of video display means) described later, the unit image signal is muted (that is, the video screen represented by the unit image signal is made uniform. Signal processing such as processing to replace with a black screen).
For example, when the channel is switched, a distorted video screen with visually uncomfortable feeling is generated. The mute process is intended to maintain the visual comfort of video output devices (such as television receivers) by displaying a uniform black screen instead of displaying such an unpleasant distorted video screen. Etc. are used.
The video signal processing apparatus according to the present invention has two main functions for appropriately performing the mute processing for preventing the display of such a disturbed image. FIG. 1 is a conceptual diagram for explaining functions of a video signal processing apparatus according to the present invention. Hereinafter, these two functions will be described with reference to FIG.

The first function is a function for detecting whether or not the video screen for one frame displayed by the unit image signal is disturbed (hereinafter, the video screen disturbance and the unit image signal disturbance are regarded as the same). In addition, the state without disturbance is called standard, and the state with disturbance is called non-standard). That is, it is determined whether or not it is disturbed for all the unit image signals (standard image unit image signals such as 1a, 1b... Shown in FIG. 1, 2a, 2b. Whether the unit image signal is a non-standard video) is determined, and based on the determination result, it is determined whether or not mute processing is necessary for each unit image signal.
The second function delays the timing at which the unit image signal is output to the video output unit, and performs a mute process on the unit image signal that is determined to require mute processing by the first function. It is a function. That is, as described above, the video signal processing apparatus according to the present invention detects whether the unit image signal is standard or non-standard after the unit image signal is input by the first function. Then, based on the detection result, it is determined whether or not to mute each unit image signal. At this time, in order to output the unit image signal determined to require mute processing after actually performing mute processing, the unit image signal is held (temporarily stored) for at least a predetermined time required for the determination. It is necessary to keep.

(2) Schematic configuration for realizing the functions of the video signal processing apparatus according to the embodiment of the present invention Next, an overview of the television receiver X for achieving the two functions described above with reference to FIG. Is described.
FIG. 2 is a schematic configuration diagram of the video signal processing apparatus A according to the embodiment of the present invention and the television receiver X including the same.
As shown in FIG. 2, the video signal processing apparatus A according to the embodiment of the present invention includes a synchronization signal separation circuit 5, a video signal processing circuit 6, a non-standard determination circuit 7, a control unit 8, a display processing circuit 9, and the like. Have In addition to the video signal processing device A, the television receiver X includes an external device interface 3, a switch unit 4 (video signal switch 4a, audio signal switch 4b), a liquid crystal controller 10, a liquid crystal driver 11, and a liquid crystal panel. 12, an audio output processing circuit 13, a speaker 14, and the like. Details of each of these elements will be described later.
The external device interface unit 3 has a function of connecting an external device such as a video device Y (video playback / recording device) and inputting the video image signal and the audio signal from the external device.

A video device Y, which is an example of an external device, is connected to the switch unit 4 via the external device interface unit 3. The switch unit 4 includes a video signal switch 4a to which a plurality of video signals are input and an audio signal switch unit 4b to which a plurality of audio signals are input. The video signal switch 4a is connected to a plurality of video video signals input from the external device interface unit 3 (video video signals input from the external device interface unit 3, not shown) according to a control command from the control unit 8 described later. , A moving image signal extracted and detected by a terrestrial analog tuner, a moving image signal extracted and detected by a BS, CS tuner (not shown), and the like. Similarly, the audio signal switch 4b selects one of a plurality of input audio signals in accordance with a control command from the control unit 8. The control unit 8 controls the video signal switch 4a and the audio signal switch 4b in accordance with an operation input for selecting a viewing channel by the viewer.
As will be described in detail later, the moving image signal is composed of unit image signals representing image information for one frame. The moving image signal selected and input by the image signal switch 4a is input to the synchronization signal separation circuit 5 and the image signal processing circuit 6. Based on the synchronization separation level set by the control unit 8 from the end image signal constituting the moving image signal input to the synchronization signal separation circuit 5, as will be described in detail later, a vertical synchronization signal and The horizontal sync signal is separated. These separated signals are input to the non-standard determination circuit 7 and the display processing circuit 9.

The non-standard determination circuit 7 determines whether the unit image signal of the separation source is standard or non-standard from the vertical synchronization signal and the horizontal synchronization signal separated and input by the synchronization signal separation circuit 5. Is done. The determination result is input to the control unit 8.
Based on the determination result by the non-standard determination circuit 7, the control unit 8 determines whether or not to mute each unit image signal. The control unit 8 includes an MPU and its peripheral devices such as ROM and RAM, and performs overall control of the television receiver X by executing a control program stored in the ROM. Is. For example, a control signal for actually performing the mute process is input to the display processing circuit 9 based on the determination result of whether or not the unit image signal is subjected to the mute process.

On the other hand, the moving image signal inputted to the image signal processing circuit 6 is subjected to various image processing such as A / D conversion and three-dimensional Y / C separation (extraction of luminance signal and color signal). The video signal processing circuit 6 has an image memory 6a for storing the unit image signal. Each of the unit image signals is temporarily stored in the image memory 6a, and the unit image signal (the luminance signal) is stored. , Color signal) is delayed by a predetermined time. The luminance signal and color signal extracted by the video signal processing circuit 6 are input to the display processing circuit 9.
As described above, the display processing circuit 9 includes the luminance signal extracted by the video signal processing circuit 6, the color signal, and the vertical synchronization signal and the horizontal synchronization signal separated by the synchronization signal separation circuit 5. A signal is being input. The display processing circuit 9 performs generation of a video screen signal based on those input signals, format conversion processing, and the like. The video screen signal is input to the liquid crystal controller 10.
The liquid crystal controller 10 inputs a control signal to the liquid crystal driver 11 based on the video screen signal generated by the display processing circuit 9. The liquid crystal driver 11 drives the liquid crystal panel 12 based on the control signal to display an image.

On the other hand, for the audio signal selected and input by the audio signal switch 4b, the audio output processing circuit 13 performs various signal processing (equalization processing according to the characteristics of the audio output unit, surround processing, the control unit 8). The signal level is amplified in accordance with the output volume level set to 1). Similarly to the video display processing circuit, the audio output processing circuit 13 has an audio memory 13a for storing the audio signal. The audio signal is temporarily stored in the audio memory 13a, and the output of the audio signal is delayed by a predetermined time. Further, the delay time is controlled to be the same as the delay time of the output of the unit image signal (the luminance signal and the color signal) by the video signal processing circuit 6.
In this way, the audio signal whose output is delayed is output by the audio output unit 14 including a speaker or the like.
In addition to the above-described configuration, the television receiver X has various configurations for operating as a normal television receiver (for example, a tuner for inputting a television broadcast signal, and a moving image video signal from the input television broadcast signal). , A detection circuit for extracting an audio signal, etc.), which are not particularly related to the features of the present invention, and thus the description thereof is omitted.

(3) Details of the first function (detection of disturbance of the unit image signal) of the video signal processing apparatus according to the embodiment of the present invention FIG. 3 shows the interlace of the signal transmission method employed in this embodiment. It is a conceptual diagram which shows the detailed structure of the said moving image video signal in a system. Hereinafter, the detailed configuration of the moving image signal in the interlace method will be described with reference to FIG. Note that this description does not indicate that the application target of the present invention is limited to the interlace method, and the present invention can be similarly applied to a moving image signal employing a progressive scanning method or the like.
The moving picture video signal processed by the video signal processing circuit 6 is obtained by continuously arranging unit image signals in a time division manner. That is, the unit image signal is a signal representing an image for one frame (that is, one still image) constituting the moving image signal. The unit image signal includes a horizontal sync pulse 15 indicating a scan line break for substantially horizontally searching a display screen on which the still image is displayed, and an odd field and even field break that divides one frame into two. The vertical synchronizing pulses 16 shown are each arranged at a predetermined period. The luminance and color information 17 of each pixel of the still image is superimposed on the gap between these pulses.
A signal obtained by removing the luminance and color information 17 from the unit image signal (that is, a signal including the horizontal synchronizing pulse 15 and the vertical pulse synchronizing 16) is called a composite signal (or a composite synchronizing signal). The composite signal is formed as a signal obtained by synthesizing a horizontal synchronizing signal corresponding to the horizontal synchronizing pulse 15 and a vertical synchronizing signal corresponding to the vertical synchronizing pulse 16 and performing a predetermined operation. When the above signal processing (reverse operation of the predetermined operation, differentiation processing, integration processing, etc.) is performed, the horizontal synchronization signal and the vertical synchronization signal can be extracted. Hereinafter, the horizontal synchronization signal and the horizontal synchronization pulse 15 are collectively referred to as a horizontal synchronization equivalent signal. The vertical synchronization signal and the vertical synchronization pulse 16 are collectively referred to as a vertical synchronization equivalent signal. Hereinafter, description will be made using a horizontal synchronization signal and a vertical synchronization signal.

FIG. 4A is a conceptual diagram showing the operation of the synchronization signal separation circuit 5. When the unit image signal having the structure as described above is input, as shown in FIG. 4A, the vertical synchronization signal and the horizontal signal are generated by the synchronization signal separation circuit 5 including a differentiation circuit, an integration circuit, and the like. A synchronization signal is separated from the unit image signal. The separated vertical synchronization signal and horizontal synchronization signal are input to the non-standard determination circuit 7 and used to determine whether the unit image signal is standard or non-standard.
When the unit image signal is standard, it is known that the frequency of the horizontal synchronizing signal takes a known value (hereinafter referred to as standard frequency fH0) (for example, 15.734 kHz in the case of the NTSC system). . In addition, the number of horizontal synchronization signals included in the unit image signal for one frame (that is, in two sections divided by the vertical synchronization signal) is also a known number (hereinafter referred to as a standard number NH0). (For example, in the case of the NTSC system, there are 525 lines).
That is, the actual value (hereinafter referred to as measurement frequency fH) of the frequency of the horizontal synchronization signal is compared with the standard frequency fH0, and the actual value (hereinafter referred to as the number of horizontal synchronization signals included in the unit image signal for one frame). It is appropriate to determine that the unit image signal is non-standard when the difference between them is large by comparing the standard number NH0 with the standard number NH0.

In the present embodiment, based on both of the above two determination methods (a method based on the frequency of the horizontal synchronization signal and a method based on the number of horizontal synchronization signals in two intervals divided by the vertical synchronization signal), A determination circuit 7 (an example of a part of the mute necessity determination unit) determines whether the unit image signal is standard (that is, detects a disturbance). More specifically, when both of the difference between the measurement frequency fH and the standard frequency fH0 is large and the difference between the measurement number NH and the standard number NH0 occurs (that is, in any determination method). The unit image signal is determined to be non-standard. Such standard / non-standard determination is performed for each of the unit image signals sequentially input.
FIG. 4B is a diagram showing a schematic configuration of the non-standard determination circuit 7. As shown in FIG. 4B, the nonstandard determination circuit 7 includes a clock counter 18, a horizontal synchronization signal frequency calculation circuit 19, a horizontal synchronization counter 20, and a determination circuit 21.
The clock counter 18 and the horizontal synchronizing signal frequency calculation circuit 19 are used to measure (calculate) the measurement frequency.
FIG. 5A is a flowchart showing a processing procedure for determining whether or not the unit image signal is non-standard using the horizontal synchronization signal. These procedures can be achieved by an individual circuit as shown in FIG. 4B or by using a computer. A procedure for determining whether or not the unit image signal is non-standard based on the frequency of the horizontal synchronization signal will be described below with reference to FIGS. 4B and 5A. S1, S2,... Shown below represent identification codes of processing procedures (steps), and are started from the processing of step S1.

The clock counter 18 receives the horizontal synchronizing signal and a clock signal generated by a clock signal generator (not shown). In step S1, the clock counter 18 calculates the input period of the horizontal synchronizing signal based on the clock signal. The calculation result is input to the horizontal synchronizing signal frequency calculation circuit 19 and converted to the frequency fH. In this way, the measurement frequency fH is obtained.
In step S2 following step S1, the measurement frequency fH is input to the determination circuit 21, where it is compared with the standard frequency fH0, that is, the difference between them is calculated. If the difference between the measurement frequency fH and the standard frequency fH0 is not less than a first threshold value f0 stored in advance in a storage unit (not shown) in the determination circuit 21, the unit image signal is non-standard. Determined. On the other hand, if it is smaller than the first threshold value f0, it is determined that the unit image signal is standard, and the process returns to step S1, and the calculation of the input period of the horizontal synchronizing signal is repeated by the clock counter 18.

FIG. 5B is a flowchart showing a processing procedure for determining whether or not the unit image signal is non-standard using the vertical synchronization signal. The procedure for determining whether or not the unit image signal is non-standard in the non-standard determination circuit 7 will be described below with reference to FIGS. 4B, 5A, and 5B. S3, S4,... Shown below represent identification codes of processing procedures (steps), and are started from the processing of step S3.
The horizontal synchronization counter 20 is supplied with the horizontal synchronization signal and the vertical synchronization signal separated by the synchronization signal separation circuit 5, and in step S3, the horizontal synchronization counter 20 causes the unit image signal to be generated one by one. The number of the horizontal synchronizing signals included in the vicinity (that is, around one frame) (the measurement number NH) is measured.
In step S4 following step S3, the measurement number NH is input to the determination circuit 21, where a difference from the standard number NH0 is calculated. If the difference is equal to or greater than the second threshold value N0 stored in the storage unit, the unit image signal is determined to be non-standard. On the other hand, if it is smaller than the second threshold N0, it is determined that the unit image signal is standard, and the process returns to step S3, and the calculation of the number of the horizontal synchronization signals included in one unit image signal is repeated. .
The first threshold value f0 and the second threshold value N0 are arbitrarily variable by an operation input.

(4) Determination of whether or not mute processing is necessary for a unit image signal in the video signal processing device As described above, the determination circuit 21 determines which one of the two determination results based on any of the above two determination results. When it is determined that the result is also non-standard, it is determined (finally) that the unit image signal is non-standard. On the other hand, if it is determined that any result is not non-standard, the unit image signal is determined to be standard. Such determination results (hereinafter referred to as standard non-standard determination results) are sequentially input to the control unit 8 for each of the unit image signals.
The control unit 8 determines whether or not mute processing is necessary for each of the unit image signals based on the determination result by the non-standard determination circuit 7.
FIG. 6A is a flowchart showing the processing procedure of the control unit 8 until the start of the mute processing based on the determination as to whether or not the unit image signal is non-standard. Note that S5, S6,... Shown below represent identification codes of processing procedures (steps), and are started from the processing of step S5. These processes are all executed by the control unit 8.

In step S5, 0 is substituted for a predetermined variable N used in the program that executes the process. The variable N indicates the number of frames in which the non-standard unit image signal is continuous. In other words, it is a number indicating how many frames of non-standard determination by the non-standard determination circuit 7 are continued.
In step S6 following step S5, each time a new standard nonstandard determination result is input, it is determined whether or not it is a standard. If it is determined that it is standard (NO in S6), the process returns to step S5, and after 0 is substituted for the variable N, it is determined whether or not the next standard non-standard determination result input is standard. Done. It is assumed that a standby is performed from the previous determination until the next standard nonstandard determination result is input, and the process of step S6 is performed each time a new standard nonstandard determination result is input.
On the other hand, if it is determined that it is non-standard (YES in S6), the process proceeds to step S7. After 1 is added to the variable N, the process proceeds to step S8.

In step S8, it is determined whether or not the variable N is 2 or more, that is, whether or not the non-standard unit image signal is continued twice or more (2 frames or more). If it is repeated twice or more (for two frames or more) (YES in S8), it is determined that mute processing is necessary. Further, a predetermined mute command signal is input to the display processing circuit 9, and a mute process is performed on a portion where the non-standard unit image signals are continuous.
On the other hand, if it is determined that two or more times (two frames or more) are not consecutive, it is determined that mute processing is not necessary for those unit image signals, and the process returns to step S6 to newly input standard non-standard The determination whether the standard determination result is standard or non-standard is repeated.
As described above, the non-standard determination circuit 7 determines whether the unit image signal is standard or non-standardized (disturbance is detected), and the control unit 8 determines the unit image signal based on the determination (disturbance detection) result. Whether or not mute processing is necessary is determined for each unit image signal. In addition, when disturbance is detected for two (a plurality of examples) of the unit image signals that are sequentially input, it is determined that mute processing is necessary for the two consecutive unit image signals (for two frames). The The non-standard determination circuit 7 and the control unit 8 are an example of a mute necessity determination unit.

(5) Release of mute processing for unit image signal in the video signal processing device The control unit 8 inputs a mute command signal to the display processing circuit 9 and performs mute processing on the unit image signal. When started, it is next determined whether or not to cancel the mute processing of the process. FIG. 6B shows the process until the mute processing is canceled based on the determination of whether or not the unit image signal is non-standard. 3 is a flowchart showing a processing procedure of the control unit 8. The following S9, S10,... Represent the identification code of the processing procedure (step), and start from the processing of step S9. These processes are all executed by the control unit 8.
In step S9, a predetermined variable M used in the program for executing the process, specifically, a number indicating how many times the standard determination by the non-standard determination circuit 6 has been continued (how many frames have been continued) is 0. Is substituted.

In step S10 following step S9, each time a new standard nonstandard determination result is input, it is determined whether or not it is a standard. If it is determined that it is non-standard (NO in S10), the process returns to step S9, and after substituting 0 for the variable M, it is determined whether or not the next standard non-standard determination result is standard. Is done.
On the other hand, if it is determined that it is standard (YES in S10), the process proceeds to step S11, 1 is added to the variable M, and then the process proceeds to step S12.
In step S12, it is determined whether or not the variable M is equal to or greater than 2, that is, whether or not the standard unit image signal is continued twice or more. If it continues for two or more times (YES in S12), it is determined that the mute process should be released, and a predetermined mute release command signal is input to the display processing circuit 9.
On the other hand, if it is determined that it is not continuous twice or more, it is determined that mute processing is still necessary for those unit image signals, and the process returns to step S10, and the newly input standard nonstandard determination result is obtained. Repeat the determination of standard or non-standard.

(6) Details of the second function (delay and mute processing of the unit image signal) of the video signal processing apparatus according to the embodiment of the invention As described above, the non-standard unit image signal is equivalent to two frames. If it is continuous, it is determined that the unit image signal should be muted. Therefore, in order to determine whether or not mute processing is necessary for a certain unit image signal, it is necessary to complete at least determination whether or not the next unit image signal is non-standard. In addition, it takes time to perform the processing shown in the flowcharts of FIGS. 6A and 6B, the transmission of the mute command signal and the mute release command signal, and the like. In this embodiment, it is assumed that the time required to determine whether or not mute processing is necessary stably including all of them is just two frames. The predetermined time required for determining whether or not mute processing is necessary for two frames is called a predetermined time.
Therefore, the image memory 6a always stores the unit image signals (two unit image signals) for two frames while sequentially updating them in the order of input.

That is, as shown in FIG. 1, when unit image signals in the video signal processing circuit 6 are inputted in the order of unit image signals 1a, 1b,..., They are temporarily stored in the image memory 6a and output. Delayed. For example, at the time when the unit image signal 2a which is the second after the unit image signal 1a is input, the luminance signal and the color signal extracted from the unit image signal 1a are output to the display processing circuit 9. Is called. Since the predetermined time required for determining whether or not the mute processing is necessary is exactly two frames, the unit image signal 2a is also input to the video signal processing circuit 6 (that is, the unit image). The units of the unit image signal 1a and the next unit image signal 1b are referred to at the same time the luminance signal and color signal extracted from the signal 1a are output to the display processing circuit 9). Signals (the mute command signal and the mute release command signal) indicating the result of determining whether or not mute processing is necessary for the image signals 1 a and 1 b are output from the control unit 8, and are output to the display processing circuit 9. Entered. The display processing circuit 9 applies the command signal to the unit image signal (specifically, the luminance signal and the color signal extracted from the unit image signal) input simultaneously with and after the command signal. If the mute processing based on the above is performed, the mute processing is performed on the unit image signal that is determined to require the mute processing without mistakenly being subjected to the mute processing. For example, if it is determined that the unit image signal 2a and the unit image signal 2b are continuously non-standard, a mute command signal for performing a mute process on the unit image signal 2a and the unit image signal 2a (the signal) (Brightness signal and color signal extracted from the above) are simultaneously input to the display processing circuit 9, so that the unit image signal 2a and the unit image signal 2b input thereafter are muted.
In this way, the image memory 6a is used for a predetermined time required for determining whether or not mute processing is required for each unit image by the non-standard determination circuit 7 and the control unit 8 (an example of a mute necessity determination unit). The unit image signal is stored and the time sequentially output to the liquid crystal panel 12 (video display means) is delayed. The image memory 6a and the video signal processing circuit 6 are examples of video signal delay means. Further, the display processing circuit 9 (an example of a mute processing unit) determines whether or not mute processing is necessary for each of the unit images by the non-standard determination circuit 7 and the control unit 8 (an example of a mute necessity determination unit). According to the determination result, mute processing is performed on the unit image signals sequentially output from the video signal processing circuit 6 (video signal delay means).

In the above-described embodiment, when it is determined that two unit image signals (unit image signals for two frames) are continuously non-standard, the mute process is performed on the two unit image signals. Although shown, it is not restricted to this, When a non-standard unit image signal continues for 3 frames, you may perform a mute process with respect to them. Further, even when the non-standard unit image signal is present alone (not continuous), it may be determined that mute processing is necessary for the single unit image signal. In addition, the number of consecutive times determined to be non-standard in the condition for determining that mute processing is necessary may be changed by an operation input.
Furthermore, even if the standard image or nonstandard determination is not necessarily performed for each unit image signal (for each frame), half of the unit image signal (one field) is set as a minimum unit, and the standard image or nonstandard determination is performed. It may be done. In that case, for example, in the case where three field non-standard determinations are continued, the mute processing may be performed on the moving image signals for the three fields. Similarly, standard or non-standard determination may be collectively performed on two consecutive unit image signals (unit image signals for two frames).
In addition, as in these examples, when changing the condition for determining that mute processing is necessary (how many non-standard frames or fields are continued), naturally, the time required for the determination (predetermined time) Time) also changes. In addition, the time for determining whether or not mute processing is necessary varies depending on the configuration of the entire system and the input paths of various signals. Accordingly, it is desirable that the delay time by the video signal processing circuit 9 (the time during which the unit image signal is stored in the image memory 9a) can be changed by operation input in accordance with such changes.

In the above-described embodiment, the difference between the measurement frequency fH and the standard frequency fH0 is large (see FIG. 5A), and the difference between the measurement number NH and the standard number NH0 is large (see FIG. 5B). An example has been disclosed in which the unit image signal is determined to be non-standard when both occur (that is, when it is determined to be non-standard in any of the determination methods). It is not a thing.
That is, although not necessarily desirable from the viewpoint of determination accuracy, the difference between the measurement frequency fH and the standard frequency fH0 is large (see FIG. 5A), and the difference between the measurement number NH and the standard number NH0 is large. If one of the above occurs, the unit image signal may be determined to be non-standard.
Instead of using the number of measurements, that is, the number of horizontal synchronization signals included in one unit image signal (per frame) for non-standard determination, a horizontal synchronization counter 20 and a determination circuit 21 (FIG. 4 ( A circuit for measuring the frequency of the vertical synchronizing signal may be provided on the path connecting with b), and the measured value of the frequency may be used for non-standard determination. That is, the frequency of the vertical synchronizing signal in the case of the standard is a known value (for example, 59.94 Hz in the NTSC system), and when the difference between the known value and the measured value is large, the unit image signal is not Assume that it is standard.

In the above-described embodiment, the mute processing for the unit image signal is performed by the control of the display processing circuit 9 (see FIG. 2). However, the present invention is not limited to this. Control for displaying a mute screen on the liquid crystal panel 12 may be performed.
Further, an image memory 6a may be provided in the display processing circuit 9 so that the unit image signal is stored in the display processing circuit 9 and output is delayed.
In addition, various modifications can be considered without departing from the scope of the present invention.

The conceptual diagram explaining the function of the video signal processing apparatus which concerns on this invention. 1 is a schematic configuration diagram of a television receiver X according to an embodiment of the present invention. The conceptual diagram which shows the detailed structure of a moving image signal. The conceptual diagram which shows the effect | action of the synchronizing signal separation circuit 5 which the television receiver X which concerns on embodiment of this invention has, and the block diagram which shows schematic structure of the nonstandard determination circuit 7. 6 is a flowchart showing a processing procedure for determining whether or not the unit image signal is non-standard using a horizontal synchronization signal or a vertical synchronization signal by the video signal processing apparatus A according to the embodiment of the present invention. The flowchart which shows the process sequence from the start of the mute process based on determination whether the unit image signal is non-standard by the video signal processing apparatus A which concerns on embodiment of this invention, and the cancellation | release of a mute process.

Explanation of symbols

A ... Video signal processing device X according to an embodiment of the present invention ... Television receiver Y equipped with video signal processing device A ... Video device (external device)
3 ... external device interface 4 ... switch unit 5 ... synchronization signal separation circuit 6 ... video signal processing circuit 7 ... non-standard determination circuit 8 ... control unit 9 ... display processing circuit 10 ... liquid crystal controller 11 ... liquid crystal driver 12 ... liquid crystal panel 13 ... Audio output processing circuit 14 ... audio output unit 18 ... clock counter 19 ... horizontal synchronization signal frequency calculation circuit 20 ... horizontal synchronization counter 21 ... determination circuit

Claims (4)

Video signal processing apparatus for performing mute processing when a plurality of unit image signals constituting a moving image signal are sequentially input and the unit image signal is disturbed when the unit image signal is sequentially output to the video display means Because
A mute necessity determining means for detecting disturbance of the unit image signal and determining the necessity of mute processing for each of the unit image signals based on the detection result;
Video signal delay means for sequentially outputting each of the unit image signals to the video display means by delaying the unit image signals by a predetermined time or more necessary for determining whether mute processing is necessary for each unit image signal by the mute necessity determining means;
Mute processing means for performing mute processing on the unit image signals sequentially output by the video signal delay means according to the determination result by the mute necessity determination means;
A video signal processing apparatus comprising:   The mute necessity determining means determines that mute processing is necessary for a plurality of the unit image signals when the disturbance is continuously detected for the plurality of unit image signals sequentially input. Item 2. The video signal processing device according to Item 1.   3. The mute necessity determining unit according to claim 1, wherein the unit image signal is detected based on a vertical synchronization signal and / or a horizontal synchronization signal in the video signal. Video signal processing device. An external video signal input means for inputting a video signal from outside;
The video signal processing device according to claim 1, wherein mute processing is performed on the moving image video signal input by the external video signal input unit;
A television receiver, comprising:

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