JP2008252761A - Video signal processor, and video signal processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and smoothly switch video without any sense of incongruity. <P>SOLUTION: When a video signal is switched from a first video signal to a second video signal and output, an average luminance level is discriminated in a step ST42, and a signal level of a video signal for synthesis is set in a step ST43 according to the discriminated average luminance level. In a step ST44, the first video signal is switched to the video signal for synthesis and mute operation is started. In a step ST45, the video signal is switched from the first video signal to the second video signal and the mute operation is ended in a step ST46. The switching from the first video signal to the second video signal is performed during mute display based upon the video signal for synthesis having a signal level corresponding to the average luminance level of the first video signal, so video can easily and smoothly be switched without any sense of incongruity. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video signal processing apparatus and a video signal processing method. Specifically, when the video signal to be output is switched from the first video signal to the second video signal, a synthesis video signal having a signal level corresponding to the average luminance level of the first video signal is generated and the first video signal is generated. By switching to the video signal, the first video signal is muted after switching to the first video signal, and then the first video signal is switched to the second video signal. After switching to the second video signal, the mute operation is canceled By switching from the composite video signal to the second video signal, the video can be switched smoothly without a sense of incongruity.

  Conventionally, in a video signal processing apparatus, for example, a television apparatus that displays video based on a video signal, the input video signal can be switched by switching the broadcasting system, switching the channel, switching the input terminal, etc. according to the user operation. It is made like that.

  In a video signal processing apparatus capable of switching such an input video signal, processing is performed so that the screen can be switched smoothly without a sense of incongruity when the input video signal is switched. For example, in the invention of Patent Document 1, writing to the image memory is stopped based on the video switching signal, the video at that time is still displayed for a predetermined period, and after the switching of the input video signal is completed, 1 to the image memory is displayed. By writing n times (m is a natural number) every other field, where n is the number of write lines or write pixels per time, the number of write lines or the number of write pixels is increased according to the calculation of n × m. It is disclosed that an image is gradually switched from one of the upper, lower, left and right directions of the screen or in a combined vertical and horizontal direction.

  In the invention of Patent Document 2, the video data writing area to the memory is changed over time from a part of the memory area to the whole memory area at the time of channel switching, and the video screen before switching is stopped at the time of channel switching. The video screen after channel switching is enlarged with the passage of time.

  Further, in a video signal processing apparatus capable of switching an input video signal, the entire screen is displayed in black to prevent noise generated when the input video signal is switched.

JP-A-11-103470 JP-A-2-278972

  By the way, in the case of controlling the writing of the video signal to the image memory and smoothly switching the screen without a sense of incongruity, an image memory is necessary, and the video signal processing apparatus cannot be configured at low cost.

  In addition, when an image memory for performing various video signal processing is provided, an image memory having a large memory capacity is required if the screen is switched smoothly without a sense of incongruity using this image memory. End up. In addition, since access to the image memory increases, for example, when real-time processing of a video signal using the image memory is performed, there is a risk of causing a delay in the real-time processing.

  Further, when the entire screen is displayed in black when the input video signal is switched, if the video is dark before and after the switching, the screen can be switched smoothly without a sense of incongruity by preventing noise. However, when the video is bright before and after switching, the screen appears to be flashed when the input video signal is switched. In addition, when the switching of the input video signal is continuously repeated as in the case of channel switching, the screen becomes a blinking state, resulting in a dazzling display with reduced quality.

  Accordingly, the present invention provides a video signal processing apparatus and a video signal processing method that can easily and smoothly switch video images without a sense of incongruity.

  The concept of the present invention is that when the video signal to be output is switched from the first video signal to the second video signal, the first video signal is synthesized with a signal level corresponding to the average luminance level of the first video signal. After switching to the video signal, the first video signal is switched to the second video signal. After switching to the second video signal, the mute operation is canceled and the output video signal is synthesized. The video signal is switched to the second video signal.

  A video signal processing apparatus according to the present invention includes a signal processing unit that detects an average luminance level of a video signal, a signal generation unit that generates a video signal for synthesis having a signal level corresponding to the average luminance level detected by the signal processing unit, and A signal switching processing unit that switches between the video signal and the video signal for synthesis, and a control unit that controls switching of the video signal and control of the signal switching processing unit, and the control unit supplies the signal switching processing unit When the video signal is switched from the first video signal to the second video signal, the video signal output from the signal switching processing unit is changed according to the average luminance level of the first video signal from the first video signal. The video signal output from the signal switching processing unit after switching to the second video signal after switching to the second video signal after switching to the composite video signal of the signal level Composite video signal From those for switching the second video signal.

  The video signal processing method includes a signal processing step of detecting an average luminance level of the first video signal in the video signal processing method of switching the video signal to be output from the first video signal to the second video signal; A signal generating step for generating a video signal for synthesis having a signal level corresponding to the average luminance level detected in the processing step, and a first switching processing step for switching the output video signal from the first video signal to the video signal for synthesis. And after the first switching processing step, the second switching processing step for switching the first video signal to the second video signal, and the video signal to be output after switching to the second video signal. A third switching step for switching from the composite video signal to the second video signal is provided.

  According to the present invention, when a synthesis video signal having a signal level corresponding to the average luminance level of the first video signal is generated and the output video signal is switched from the first video signal to the second video signal, After the video signal to be output is switched from the first video signal to the video signal for synthesis, the first video signal is switched to the second video signal and output after switching to the second video signal. The video signal is switched from the composite video signal to the second video signal. For this reason, it is possible to easily and smoothly switch images without a sense of incongruity.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The video signal processing device is a device capable of switching video signals. For example, video recording and recording of video signals using a television device and a recording medium (magnetic tape, magnetic disk, optical disk, semiconductor memory, etc.) Playback devices, set-top boxes, and the like. In the following description, it is assumed that the video signal processing device is a television device.

  FIG. 1 shows the configuration of a video signal processing apparatus. The video signal processing apparatus 10 has a function of receiving broadcast signals such as terrestrial analog broadcast, terrestrial digital broadcast, and digital satellite broadcast. The satellite broadcasting antenna 11 is an antenna that receives digital satellite broadcasting, and the reception signal RF1 received by the satellite broadcasting antenna 11 is supplied to the satellite broadcasting tuner 12. The satellite broadcast tuner 12 supplies an intermediate frequency signal RS1 obtained by selecting a desired channel (frequency) to the digital demodulator 13. The digital demodulation unit 13 performs a demodulation process corresponding to a modulation method used in satellite broadcasting, for example, a QPSK demodulation process, and supplies the obtained transport stream TS1 to the stream switching unit 21. The channel selection operation of the satellite broadcast tuner 12 is controlled by a control signal CT from the control unit 50 described later.

  The terrestrial broadcast antenna 15 is an antenna that receives terrestrial broadcasts, and the reception signal RF 2 received by the terrestrial broadcast antenna 15 is supplied to the terrestrial broadcast tuner 16. The terrestrial broadcast tuner 16 supplies an intermediate frequency signal RS2 obtained by selecting a desired channel to the digital demodulator 17 when receiving a terrestrial digital broadcast. The terrestrial broadcast tuner 16 supplies the video / audio demodulator 26 with the intermediate frequency signal RS3 obtained by selecting a desired channel when receiving the terrestrial analog broadcast. The digital demodulator 17 performs demodulation processing corresponding to the modulation scheme used in terrestrial digital broadcasting, for example, QFDM demodulation processing, and supplies the obtained transport stream TS2 to the stream switching unit 21.

  When receiving the digital satellite broadcast, the stream switching unit 21 selects the transport stream TS1 and supplies it to the demultiplexer 22. When receiving terrestrial digital broadcasting, the transport stream TS2 is selected and supplied to the demultiplexer 22.

  The demultiplexer 22 separates the video data DTv, the audio data DTa, the broadcast data DTd, etc. included in the transport streams TS1, TS2 in a time-division multiplexed manner, and the video data DTv and the audio data DTa are decoded. The broadcast data DTd is supplied to the broadcast data processing unit 24.

  The decoder unit 23 decodes the video data DTv and supplies the obtained video signal VSa to the video switching unit 31. The decoder unit 23 decodes the audio data DTa and supplies the obtained audio signal Asa to the audio switching unit 41.

  The broadcast data processing unit 24 generates a control signal CS for performing predetermined processing according to a user operation, for example, EPG (Electric Program Guide) display, and supplies the control signal CS to the signal generation unit 33.

  The video / audio demodulator 26 demodulates the intermediate frequency signal RS3 supplied from the terrestrial broadcast tuner 16 when receiving the terrestrial analog broadcast, converts the obtained video signal into a digital video signal VSb, and switches the video. Is supplied to the unit 31, and the obtained audio signal ASb is supplied to the audio switching unit 41.

  An external input terminal 28 is connected to the video switching unit 31, and a composite method, a component method, an HDMI (High Definition Multimedia Interface) method, a DVI (Digital Visual Interface) method is used from an external device via the external input terminal 28. The video signal can be input. Further, a signal processing unit 32 is connected to the video switching unit 31, and the video signal supplied to the signal processing unit 32 is changed to the video signal VSa supplied from the decoder unit 23 and the video signal from the video / audio demodulation unit 26. Switching to VSb or one of the video signals VSC supplied via the external input terminal 28 is performed.

  The signal processing unit 32 uses the video signal VSd supplied from the video switching unit 31 to perform interlace / progressive conversion (I / P conversion) processing, pixel number conversion processing, and the like as necessary. VSe is supplied to the composition processing unit 34. In addition, the signal processing unit 32 detects the average luminance level of the video signal VSd and supplies the average luminance level signal YL indicating the detection result to the control unit 50. For example, when the supplied video signal VSd is composed of a luminance signal and a color difference signal, the signal processing unit 32 generates an average luminance level signal YL by averaging the luminance signals. When the video signal VSd is a primary color signal, a composite signal, or the like, a luminance signal is generated, and the generated luminance signal is averaged to generate an average luminance level signal YL. Here, when the video signal VSe output from the signal processing unit 32 is a progressive method, the average luminance level signal YL is generated by averaging the luminance signals in units of frames. When the video signal VSe is an interlace method, the luminance signal is averaged in field units to generate an average luminance level signal YL. The signal processing unit 32 is connected to a memory 32a, and the memory 32a is used to perform an I / P conversion process, a pixel number conversion process, and the like.

  The signal generation unit 33 generates an on-screen display video signal VSosc based on a control signal CS supplied from the broadcast data processing unit 24 or a control signal CT from a control unit 50 described later, and supplies the generated video signal VSosc to the synthesis processing unit 34. . For example, the signal generation unit 33 generates an on-screen display video signal VSosc for performing EPG display, channel display, and the like based on the control signal CS supplied from the broadcast data processing unit 24 and the control signal CT from the control unit 50. It is generated and supplied to the synthesis processing unit 34. Further, the signal generation unit 33 generates a synthesis video signal VSf based on the control signal CT from the control unit 50 and supplies it to the synthesis processing unit 34. This composite video signal VSf is, for example, a single-display video signal for performing a video fade-out / fade-in operation or a mute operation when a signal switching operation is performed as described later.

  The synthesis processing unit 34 combines the video signal VSe supplied from the signal processing unit 32 with the on-screen display video signal VSosc and the synthesis video signal VSf supplied from the signal generation unit 33 to generate a video output signal VSg. This is supplied to the output processing unit 35. Further, when the on-screen display video signal VSosc and the synthesis video signal VSf are synthesized with the video signal VSe, the synthesis processing unit 34 performs a so-called alpha blending process, and the video signal VSe and the video signal for synthesis in the video output signal VSg. VSf synthesis ratio can be varied.

  FIG. 2 shows the configuration of the composition processing unit 34. The video signal (for example, three primary color signals) VSe supplied from the signal processing unit 32 is supplied to the multiplier 341. The multiplier 341 multiplies the video signal VSe by the coefficient α and supplies the result to the adder 343. The synthesis video signal (for example, three primary color signals) VSf supplied from the signal generation unit 33 is supplied to the multiplier 342. The multiplier 342 multiplies the composite video signal VSf and the on-screen display video signal VSosc by a coefficient (1-α) and supplies the result to the adder 343. The adder 343 adds the video signal α × VSe supplied from the multiplier 341 and the video signal (1-α) × VSf or video signal (1-α) × VSosc supplied from the multiplier 342, and adds them. The result is supplied to the video output processing unit 35 as a video output signal VSg.

  If the composition processing unit 34 is configured in this way, the value of the coefficient α can be varied within the range of “0 ≦ α ≦ 1” by the control signal CT from the control unit 50, thereby obtaining the video signal VSe in the video output signal VSg. The composition ratio (ratio) of the composition video signal VSf can be changed.

  Connected to the video output processing unit 35 is a display unit 36 configured using a display device such as an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), an EL (Electro Luminescence), or a cathode ray tube. The video output processing unit 35 generates a display drive signal DR for driving the display device based on the video output signal VSg and supplies the display drive signal DR to the display unit 36. For this reason, video can be displayed on the display unit 36. Further, when the video output processing unit 35 supplies a video signal to an external device (not shown), the video output processing unit 35 outputs the video output signal VSg as an output signal Vout having a format corresponding to the external device.

  An external input terminal 28 is connected to the audio switching unit 41, and an audio signal ASc can be input from an external device via the external input terminal 28. Also, an audio output processing unit 42 is connected to the audio switching unit 41, and the audio signal supplied to the audio output processing unit 42 is changed from the audio signal Asa supplied from the decoder unit 23 to the audio / video demodulation unit 26. The audio signal ASb or the audio signal ASc supplied via the external input terminal 28 is switched.

  An audio output unit 43 configured using a speaker is connected to the audio output processing unit 42. The audio output processing unit 42 performs audio processing such as signal level adjustment, sound quality adjustment, noise removal processing, and the like using the audio signal ASd supplied from the audio switching unit 41, and outputs the audio output signal DRa after audio processing to the audio output unit 43 to perform audio output. Further, when the audio output processing unit 42 supplies an audio signal to an external device (not shown), the audio output processing unit 42 outputs the signal after the audio processing as an output signal Aout having a format corresponding to the external device.

  A user interface unit 51 is connected to the control unit 50. The user interface unit 51 supplies an operation signal PS corresponding to a user operation to the control unit 50, and includes, for example, an operation key and a remote control signal receiving unit.

  The control unit 50 is connected to each unit described above via the bus 55. The control unit 50 generates a control signal CT based on the operation signal PS from the user interface unit 51 and supplies the control signal CT to each unit, thereby controlling the operation of the video signal processing device to be an operation corresponding to the user operation. . For example, when the operation signal PS supplied from the user interface unit 51 indicates that a signal switching operation such as channel switching, broadcast switching, or input switching has been performed, the control unit 50 determines the desired channel or desired channel. The channel selection operation of the satellite broadcast tuner 12 and the terrestrial broadcast tuner 16, the stream switching unit 21, and the video switching so that broadcast video / audio or externally supplied video / audio can be presented. The switching operation of the unit 31 and the voice switching unit 41 is controlled. In addition, when the signal is switched, the control unit 50 controls the operations of the signal generation unit 33 and the synthesis processing unit 34 to perform a video fade-out / fade-in operation and a video mute operation, and to improve the quality at the time of signal switching. The video is switched smoothly without any deterioration and without a sense of incongruity.

  FIG. 3 is a flowchart showing an operation at the time of signal switching, and shows a case where a fade-out / fade-in operation is performed. Before the signal switching operation is performed, the coefficient α is set to “1”, and the video signal VSe supplied from the signal processing unit 32 is supplied to the video output processing unit 35 as the video output signal VSg. Shall. In the fade-out / fade-in operation, for example, a step level d indicating the amount of change of the coefficient α is set in advance, and the video signal composition ratio is changed in accordance with the step level d to perform a fade-out operation or a fade-in operation. .

  In step ST1, the control unit 50 determines whether or not a signal switching operation has been performed. The control unit 50 proceeds to step ST2 when the operation signal PS indicating the signal switching operation is supplied from the user interface unit 51, and returns to step ST1 when the operation signal PS indicating the signal switching operation is not supplied.

  In step ST2, the control unit 50 determines whether or not a subtraction result (α−d) obtained by subtracting the step level d from the coefficient α is “0” or less. The controller 50 proceeds to step ST3 when the subtraction result (α−d) is not “0” or less, and proceeds to step ST5 when the subtraction result (α−d) is “0” or less.

  In step ST3, the control unit 50 sets the subtraction result (α−d) to the coefficient α, and proceeds to step ST4. In step ST4, the control unit 50 waits for a predetermined time Tw and then returns to step ST2. Here, the control unit 50 sets the predetermined time Tw as, for example, a time in units of frame periods. In this case, the composition ratio can be switched for each frame image.

  In step ST5, the control unit 50 sets the coefficient α to “0” and proceeds to step ST6.

  In step ST6, the control unit 50 performs a switching process. For example, when it is determined that the channel switching operation has been performed by the operation signal PS, the channel to be selected is switched by the satellite broadcast tuner 12 or the terrestrial broadcast tuner 16. Further, when a program of a plurality of organized channels is broadcast on one frequency channel, the demultiplexer 22 and the decoder unit 23 are controlled so that the video signal VSa and audio signal ASa of the desired channel can be obtained. . Further, when the operation signal PS indicates that a broadcast switching operation or an input switching operation has been performed, the control unit 50 controls the stream switching unit 21, the video switching unit 31, and the audio switching unit 41 to perform a desired operation. The video signal is supplied to the signal processing unit 32 as the video signal VSd, and the desired audio signal is supplied to the audio output processing unit 42 as the audio signal ASd.

  In step ST7, the control unit 50 determines whether or not the addition result (α + d) obtained by adding the step level d to the coefficient α is “1” or more. When the addition result (α + d) is not “1” or more, the control unit 50 proceeds to step ST8, and when the addition result (α + d) is “1” or more, the control unit 50 proceeds to step ST10.

  In step ST8, the control unit 50 sets the addition result (α + d) to the coefficient α, and proceeds to step ST9. In step ST9, the control unit 50 waits for a predetermined time Tw and then returns to step ST7.

  As described above, if the step level d is sequentially subtracted from the coefficient α and the subtraction result is a new value of the coefficient α, the ratio of the video signal VSe in the video output signal VSg is reduced in a stepwise manner. The ratio of the signal VSf increases stepwise. If the step level d is sequentially added from the coefficient α and the subtraction result is a new value of the coefficient α, the ratio of the video signal VSe in the video output signal VSg increases stepwise, and the ratio of the composite video signal VSf. Decreases step by step. Therefore, if the synthesis video signal VSf is a black level signal, the signal is switched when the fade-out operation is performed and the video is black only. Further, after the signal is switched, a fade-in operation is performed so that the black-only video is sequentially switched to the video after the signal switching.

  Note that if the value of the step level d is reduced, the fade-out operation and the fade-in operation are performed smoothly. Further, by adjusting the predetermined time Tw, the speed of the fade-out operation and the fade-in operation can be adjusted. For example, if the time required for the fade-out operation and the time required for the fade-in operation are set to about 0.1 to 0.5 seconds, the video can be easily and smoothly switched without a sense of incongruity. Further, the signal switching takes time due to the fade-out / fade-in operation, and there is no delay in response to the user operation. Furthermore, not only can the step level d and the predetermined time Tw be set in advance, but if the step level d and the predetermined time Tw can be changed, a fade-out / fade-in operation with a high degree of freedom can be performed.

  Further, in the operation at the time of signal switching shown in FIG. 3, the fade-out / fade-in operation is performed by adding or subtracting the step level d to the coefficient α. However, a plurality of coefficients α are set in advance, and the predetermined time Tw is It is also possible to perform a fade-out / fade-in operation by switching the coefficient each time it passes.

  FIG. 4 shows a change in video at the time of signal switching. In FIG. 4, the composition video signal VSf is a black level signal.

  FIG. 4A shows an image when a signal switching operation is performed. Here, when the signal switching operation is performed and the fade-out operation is performed, the coefficient α is changed from “1” to a smaller value in order. Further, since the video output signal VSg is obtained by synthesizing the video signal VSe and the synthesis video signal VSf with a synthesis ratio of “α: (1-α)”, for example, when the coefficient α is “0.66”. The video at this time is darker than the video when the signal switching operation is performed, as shown in FIG. Further, when the time elapses, the coefficient α becomes a smaller value. For example, when the coefficient α becomes “0.33”, the video at this time is shown in FIG. 4B as shown in FIG. The video is darker than the video shown.

  When the time further elapses, the coefficient α is set to “0”. Therefore, the video output signal VSg indicates the composite video signal VSf, and the video at this time is displayed on a black screen as shown in FIG. Further, the switching process is performed when the image shown in FIG. 4D is displayed.

  Since the coefficient α at the end of the switching process is “0”, the video at this time continues to be displayed on the black screen as shown in FIG. When the switching process is completed and the fade-in operation is performed, the coefficient α is changed from “0” to a larger value in order. Here, when the coefficient α is “0.33”, for example, the video at this time is brighter than the video at the end of the switching process, as shown in FIG. Further, when the time elapses, the coefficient α becomes a larger value. For example, when the coefficient α becomes “0.66”, an image at this time is shown in FIG. 4F as shown in FIG. The image is brighter than the image shown.

  When the time further elapses, the coefficient α is set to “1”. Therefore, the video output signal VSg indicates the video signal VSe, and the video at this time is the video selected by the signal switching operation as shown in FIG.

  As described above, when the signal switching operation is performed, the synthesis video signal VSf is synthesized with the video signal VSe, and the fade-out / fade-in operation is performed. Therefore, it is possible to prevent deterioration in quality at the time of signal switching. Further, since the signal generation unit 33 and the synthesis processing unit 34 are used not only for fade-out / fade-in operations at the time of signal switching but also for on-screen display, video signal processing that performs EPG display or the like by alpha blending processing. In the apparatus, it is possible to prevent deterioration in quality at the time of signal switching without causing an increase in cost. Further, since the fade-out / fade-in operation is not performed using the memory 32a, the video signal processing apparatus can be configured at low cost, and the real-time processing is not delayed.

  By the way, in the above-described embodiment, since the composite video signal VSf is a black level signal, for example, when the video when the signal switching operation is performed is bright, the luminance change of the video in the fade-out operation is large. For example, when the image when the signal switching operation is performed is a bright image as shown in FIG. 5A, when the fade-out operation is performed, the image when the coefficient α is, for example, “0.66” is illustrated. 5 (B), the image when the coefficient α is, for example, “0.33” is shown in FIG. 5C, and the image when the coefficient α is “0” is shown in FIG. The brightness change of the video in the fade-out operation becomes large. Even if the composite video signal VSf is a white level signal, if the video when the signal switching operation is performed is dark, the luminance change of the video in the fade-out operation becomes large.

  For this reason, if the signal switching operation is repeatedly performed, the screen may blink slowly, or the screen may continue to blink. Therefore, the control unit 50 sets the signal level of the synthesis video signal VSf based on the average luminance level signal YL obtained by the signal processing unit 32 according to the luminance of the video when the signal switching operation is performed. Thus, the luminance change of the video in the fade-out operation is reduced.

  FIG. 6 shows a flowchart for setting the signal level of the composite video signal VSf in accordance with the brightness of the video when the signal switching operation is performed as another operation at the time of signal switching.

  In step ST21, the control unit 50 determines whether or not a signal switching operation has been performed. The control unit 50 proceeds to step ST22 when the operation signal PS indicating the signal switching operation is supplied from the user interface unit 51, and returns to step ST21 when the operation signal PS indicating the signal switching operation is not supplied.

  In step ST22, the control unit 50 determines the average luminance level. That is, the control unit 50 causes the signal processing unit 32 to generate the average luminance level signal YL, and determines the average luminance level of the video when the signal switching operation is performed based on the average luminance level signal YL. Proceed to step ST23.

  In step ST23, the control unit 50 sets the signal level of the synthesis video signal VSf. The control unit 50 sets the signal level of the compositing video signal VSf according to the average luminance level determined in step ST22 so as to reduce the luminance change of the video in the fade-out operation, and proceeds to step ST24.

  The processing from step ST24 to step ST32 corresponds to the processing from step ST2 to step ST10 in FIG. 3, and the fade-out operation can be performed by performing the processing from step ST24 to step ST27. Thereafter, a switching process is performed in step ST28 as in step ST6. Furthermore, a fade-in operation can be performed by performing the processing from step ST29 to step ST32.

  In this way, if the signal level of the compositing video signal VSf is set according to the average luminance level of the video when the signal switching operation is performed, the change in the luminance of the video in the fade-out operation can be reduced. In addition, signal switching is performed when an image having a brightness corresponding to the average luminance level of the image when the signal switching operation is performed is displayed. Further, after the signal is switched, a fade-in operation is performed to sequentially switch to the video after the signal is switched.

  FIG. 7 shows a change in video at the time of signal switching. For example, when the signal level of the composite video signal is set according to the average luminance level of the video when the signal switching operation is performed, for example, the signal switching operation is performed. This is a case where the signal level of the compositing video signal is set so that the average luminance level of the video at the same time is equal to the luminance level of the video based on the compositing video signal.

  FIG. 7A shows an image when a signal switching operation is performed. Here, when the signal switching operation is performed and the fade-out operation is performed, the coefficient α is changed from “1” to a smaller value in order. The video output signal VSg is obtained by synthesizing the video signal VSe and the synthesis video signal VSf at a synthesis ratio of “α: (1−α)”, and the signal level of the synthesis video signal VSf is a signal switching. Since it is set according to the average luminance level of the video when the operation is performed, for example, when the coefficient α is “0.66”, the video at this time is as shown in FIG. Thus, the image has the same brightness as the image when the signal switching operation is performed, and does not become a dark image as shown in FIG. Further, when the time elapses, the coefficient α becomes a smaller value. For example, when the coefficient α becomes “0.33”, the video at this time is shown in FIG. 7B as shown in FIG. The image is as bright as the image shown, and is not a darker image as shown in FIG.

  When the time further elapses, the coefficient α is set to “0”. Therefore, the video output signal VSg indicates the composite video signal VSf, and the video at this time is an average luminance level of the video when the signal switching operation is performed as shown in FIG. A certain screen is displayed.

  Since the coefficient α at the end of the switching process is “0”, the video at this time is the average luminance level of the video when the signal switching operation is performed, as shown in FIG. The screen display continues. When the switching process is completed and the fade-in operation is performed, the coefficient α is changed from “0” to a larger value in order. Here, when the coefficient α is, for example, “0.33”, the video at this time is a video including the video selected by the signal switching operation, as shown in FIG. Further, when time elapses, the coefficient α becomes a larger value. For example, when the coefficient α becomes “0.66”, the video at this time is shown in FIG. 7F as shown in FIG. The image includes more images selected by the signal switching operation than the illustrated image.

  When the time further elapses, the coefficient α is set to “1”. Therefore, the video output signal VSg indicates the video signal VSe, and the video at this time is the video selected by the signal switching operation as shown in FIG.

  As described above, when the signal switching operation is performed, the signal level of the synthesis video signal VSf is set according to the average luminance level of the video when the signal switching operation is performed, and the synthesis video signal VSf is set. Since the fade-out / fade-in operation is performed by combining with the video signal VSe, it is possible to prevent the video based on the video output signal VSg from being displayed as if the screen blinks even if the signal switching operation is repeated.

  By the way, if the signal level of the compositing video signal VSf is set according to the average luminance level of the video when the signal switching operation is performed, the luminance change in the fade-out operation can be reduced as described above. Therefore, when the signal switching operation is performed, the video mute operation is performed instead of the video fade-out / fade-in operation, but the signal quality is deteriorated or the signal blinks when the signal switching operation is repeated. Thus, it is possible to prevent the video display from being performed.

  Next, a case where a mute operation is performed when a signal switching operation is performed will be described. When performing the mute operation, the control unit 50, based on the average luminance level signal YL from the signal processing unit 32, the signal level of the synthesis video signal VSf according to the average luminance level of the video when the signal switching operation is performed. Set. Further, the control unit 50 switches the coefficient α to either “0” or “1”. At this time, the video output signal VSg output from the synthesis processing unit 34 is either the video signal VSe or the video signal VSf, and the synthesis processing unit 34 operates as a signal switching processing unit.

  FIG. 8 shows a flowchart when the mute operation is performed at the time of signal switching.

  In step ST41, the control unit 50 determines whether or not a signal switching operation has been performed. The control unit 50 proceeds to step ST42 when the operation signal PS indicating the signal switching operation is supplied from the user interface unit 51, and returns to step ST41 when the operation signal PS indicating the signal switching operation is not supplied.

  In step ST42, the control unit 50 determines the average luminance level. That is, as in step ST22 of FIG. 6, the control unit 50 causes the signal processing unit 32 to generate the average luminance level signal YL, and when the signal switching operation is performed based on the average luminance level signal YL. The average luminance level of the video is determined, and the process proceeds to step ST43.

  In step ST43, the control unit 50 sets the signal level of the synthesis video signal VSf. The control unit 50 sets the signal level of the composite video signal VSf according to the average luminance level determined in step ST42 so that the change in the luminance of the video during the mute operation is reduced, and the process proceeds to step ST44.

  In step ST44, the control unit 50 starts a mute operation. The control unit 50 switches the coefficient α from “1” to “0” and proceeds to step ST45. At this time, the video output signal VSg output from the synthesis processing unit 34 is switched from the video signal VSe to the synthesis video signal VSf. Therefore, the synthesis processing unit 34 operates as a signal switching processing unit.

  In step ST45, the control unit 50 performs a switching process and proceeds to step ST46. In this switching process, the same process as step ST6 of FIG. 3 is performed.

  In step ST46, the control unit 50 ends the mute operation. That is, the control unit 50 switches the coefficient α from “0” to “1” and ends the signal switching process.

  By performing such processing, the mute operation is performed during the switching process. The video when the mute operation is performed is a video corresponding to the average luminance level of the video when the signal switching operation is performed.

  FIG. 9 shows a video change at the time of signal switching, and is a case where a mute operation is performed. 9A and 9B show images when a signal switching operation is performed. Here, when the signal switching operation is performed and the mute operation is performed, the coefficient α is changed from “1” to “0”, and the video output signal VSg indicates the synthesis video signal VSf. Here, since the signal level of the composite video signal VSf is set according to the average luminance level of the video when the signal switching operation is performed, when the video is dark as shown in FIG. Is a dark image corresponding to the average luminance level of the image when the signal switching operation is performed as shown in FIG. 9C when the signal level of the composite video signal VSf is set low. Further, when the image is bright as shown in FIG. 9B, the signal level of the composite image signal VSf is set high, and the signal switching operation is performed as shown in FIG. 9D. The image becomes bright according to the average luminance level of the image.

  The switching process is performed during the mute period in which the images shown in FIGS. 9C and 9D are displayed. When the switching process is completed, the mute operation is terminated. That is, since the coefficient α is changed from “0” to “1”, the video output signal VSg indicates the video signal VSe. Therefore, after the end of the mute operation, as shown in FIGS. 9E and 9F, the video selected by the signal switching operation is obtained.

  As described above, when the signal level of the composite video signal VSf is set according to the average luminance level of the video when the signal switching operation is performed, even if the mute operation is performed during the switching process, the luminance due to the mute operation is increased. Since the level change can be reduced, it is possible to prevent deterioration in quality at the time of signal switching and video display as if blinking when the signal switching operation is repeated.

  When the signal level of the composite video signal is set according to the average luminance level of the video when the signal switching operation is performed, the signal level of the composite video signal is the video when the signal switching operation is performed. However, the present invention is not limited to the case where the average luminance level is set to be equal to the luminance level of the video based on the video signal for synthesis. For example, if the average brightness level of the video when the signal switching operation is performed is very high, then the video selected by the signal switching operation is darker than the video when the signal switching operation is performed There are many. Also, if the average brightness level of the video when the signal switching operation is performed is very low, then the video selected by the signal switching operation is brighter than the video when the signal switching operation is performed There are many. Therefore, when the average luminance level of the video when the signal switching operation is performed is higher than a predetermined threshold, the average luminance of the video when the signal switching operation is performed based on the video luminance level based on the composite video signal. The signal level of the composite video signal is set so as to be lower than the level. In addition, when the average luminance level of the video when the signal switching operation is performed is lower than a predetermined threshold, the average luminance of the video when the signal switching operation is performed based on the video luminance level based on the composite video signal. The signal level of the synthesis video signal is set to be higher than the level. By setting the signal level of the composite video signal in this way, it is possible to reduce the luminance level change in the fade-in operation and the luminance level change when the mute operation is finished.

It is a figure which shows the structure of a video signal processing apparatus. It is a figure which shows the structure of a synthetic | combination process part. It is a flowchart which shows the operation | movement at the time of signal switching. It is a figure which shows the image change at the time of signal switching. It is a figure which shows a video change when a video is bright at the time of signal switching. It is a flowchart which shows the other operation | movement at the time of signal switching. It is a figure which shows the image change at the time of signal switching (when other operation | movement is performed). It is a flowchart which shows the mute operation | movement at the time of signal switching. It is a figure which shows the video change at the time of signal switching (when a mute operation is performed).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Video signal processing apparatus, 11 ... Satellite broadcast antenna, 12 ... Satellite broadcast tuner, 13, 17 ... Digital demodulator, 15 ... Terrestrial broadcast antenna, 16 ... Terrestrial broadcast tuner, 21 ... stream switching unit, 22 ... demultiplexer, 23 ... decoder unit, 24 ... broadcast data processing unit, 26 ... video / audio demodulation unit, 28 ... External input terminal, 31... Video switching unit, 32... Signal processing unit, 32 a .. memory, 33... Signal generation unit, 34. , 36 ... display unit, 41 ... voice switching unit, 42 ... voice output processing unit, 43 ... voice output unit, 50 ... control unit, 51 ... user interface unit, 55 ..Bus, 341, 342 ... Multiplier, 343 - adder

Claims (3)

A signal processing unit for detecting an average luminance level of the video signal;
A signal generation unit that generates a video signal for synthesis at a signal level according to the average luminance level detected by the signal processing unit;
A signal switching processing unit for switching between the video signal and the composite video signal;
A control unit for controlling the switching of the video signal and the signal switching processing unit;
When the video signal supplied to the signal switching processing unit is switched from the first video signal to the second video signal, the control unit converts the video signal output from the signal switching processing unit to the first video signal. Switching from the first video signal to the second video signal after switching from the signal to the synthesis video signal having a signal level corresponding to the average luminance level of the first video signal; After switching to the video signal, the video signal processing apparatus switches the video signal output from the signal switching processing unit from the synthesis video signal to the second video signal. The signal switching processing unit
A first multiplier for multiplying the video signal by a coefficient α;
A second multiplier for multiplying the composite video signal by a coefficient (1-α);
An adder for adding the multiplication results obtained by the first and second multipliers;
The control unit switches the coefficient α to change the video signal output from the signal switching processing unit from the first video signal to the synthesis video signal or from the synthesis video signal to the second video signal. 2. The video signal processing apparatus according to claim 1, wherein switching is performed. In a video signal processing method for switching an output video signal from a first video signal to a second video signal,
A signal processing step of detecting an average luminance level of the first video signal;
A signal generation step of generating a video signal for synthesis with a signal level corresponding to the average luminance level detected in the signal processing step;
A first switching process for switching the output video signal from the first video signal to the synthesis video signal;
A second switching processing step of switching the first video signal to the second video signal after the first switching processing step is performed;
A video signal processing method comprising: a third switching step of switching the video signal to be output from the composite video signal to the second video signal after switching to the second video signal.