JPH0779485B2 - Video disc special playback detection circuit - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a special reproduction detection circuit for a video disc arranged in an IDTV television receiver or the like.

(Prior Art) Conventionally, IDTV, HDTV, etc. have been developed which perform various image quality improvement processes such as motion adaptive Y / C separation and conversion to progressive scan video signals by performing digital signal processing on NTSC standard television signals. Came. In addition, recently, an image quality improvement processing device for non-standard signals deviating from the NTSC standard such as a reproduction signal from a VTR (video tape recorder) or a video disc or a video signal from a video game machine is being developed. .

In general, an image quality improving apparatus that targets both standard signals and non-standard signals has a processing system for each signal, a detection circuit that detects which signal is the processing target, and a detection circuit that corresponds to the detection result. It is composed of a selection circuit for selecting a signal processing system.

By the way, the playback signal from a laser vision video disc can be processed as it is by the processing system of the NTSC standard signal because it is very similar to the NTSC standard signal, but only during special playback such as still, slow, double speed, etc. Therefore, it is necessary to detect this special reproduction and switch to the corresponding processing system.

(Problems to be Solved by the Invention) As described above, the image quality improving apparatus for the standard signal and the non-standard signal requires the detection means for detecting what the signal to be processed is. As such a detection means, a non-standard signal detection circuit for detecting a non-standard signal is usually installed.

Regarding the reproduction signal from the VTR or VHD system video disk of the β system or VHS system, and the video signal from the video game machine, the presence of jitter due to tape running and rotation irregularity and the interleave relationship are considerably broken. Focusing on the above, it is possible to detect such a non-standard signal by detecting the transfer difference between the clock signal of the color subcarrier frequency generated by the PLL and the horizontal synchronizing frequency from the color burst signal.

However, with regard to special reproduction signals such as stills from a laser vision video disc, the detection method based on the above transfer error cannot be applied because the interleaving relationship is very similar to the NTSC signal and the interleave relationship is almost unchanged. There is.

Further, when a non-standard signal detection circuit is generally realized, not limited to the special reproduction signal, it is an important issue how to realize this with a small amount of hardware.

(Means for Solving Problems) The special reproduction detection circuit for a video disc according to the present invention is
A frame delay circuit for delaying a video signal by one frame, which is commonly used with a detection circuit for detecting a motion in a display screen based on interframe correlation, and a horizontal circuit included in this video signal. The integrated value of the absolute value of the difference signal on the input / output terminals of the frame delay circuit is calculated over the appearance period of the sync signal or the vertical sync signal or both, and when the integrated value exceeds a predetermined value, the video signal is It is equipped with a computing unit that outputs a detection signal indicating that it is a non-standard signal specially reproduced from a laser vision video disk, and NT with a small amount of hardware.
It is configured to reliably detect special playback signals that are very similar to SC standard signals.

Hereinafter, the operation of the present invention will be described in detail with reference to Examples.

(Embodiment) FIG. 1 is a block diagram showing the structure of a special reproduction detection circuit of a video disk according to an embodiment of the present invention, together with the structure of the detection circuit, showing the motion of sharing a one-frame delay circuit with this circuit. It is a figure.

The special playback detection circuit of the video disk is from the video signal input terminal IN, the 1-frame delay circuit 11, the subtraction circuit 12, the absolute value circuit 21, the gate circuit 22, the integration circuit 23, the comparison circuit 24, and the detection signal output terminal OUT. It is configured.

On the other hand, the motion detection circuit is an input terminal IN for a video signal shared with the special reproduction detection circuit and a 1-frame delay circuit 11
In addition to the subtraction circuit 12, a low-pass filter circuit 13, an absolute value circuit 14, a coring circuit 15, a coefficient generation circuit 19, etc. are provided, and motion is detected in the display screen based on the interframe correlation, and the detection result is displayed. It is configured to output to the output terminal O.

The common input terminal IN is supplied with a non-standard signal such as an NTSC standard television signal or a reproduction signal from a laser vision video disc. This video signal is
Typically four times the color subcarrier frequency (4 fsc)
It is a digital composite signal sampled by.

As described above, the reproduced signal from the laser vision video disc becomes a good NTSC standard signal during normal reproduction, and therefore it can be directly processed by the image quality improvement processing system for the NTSC signal. However, only during special playback such as still, slow, and double speed, the signal is slightly different from the NTSC standard signal, and if this signal is processed by the signal processing system for NTSC, the effect of image quality improvement cannot be obtained.

That is, in the case of a CAV (constant angular velocity) type video disc, a signal for one frame is recorded on one track that makes one round, and during special reproduction of a still, one frame on the same track is recorded. Signal is repeatedly read. Further, during slow special reproduction, a signal for one frame on each track is repeatedly read a predetermined number of times. Further, during double speed special reproduction, a signal for one frame is read every other track. In this way, the NTSC standard that the phase of the color subcarrier is inverted by 180 degrees between adjacent frames by simply reading the signal for one frame on the same track repeatedly or by reading the signal for one frame every other track. It will be different from the signal.

Therefore, as shown in FIG. 2, during special reproduction such as still, slow, and double speed, the vertical blanking period of the reproduction signal is 140 ns corresponding to a half cycle of the color subcarrier (3.58 MHz) for each frame.
By expanding and contracting by ec, the phase of the color subcarrier is inverted by 180 degrees between adjacent frames. In this way, since the vertical blanking period is expanded / contracted for each frame during special reproduction such as a still image, Y / C separation using inter-frame correlation cannot be performed in image quality improvement processing. In addition, since inter-field interpolation changes the image quality for each field, inter-field interpolation cannot be performed in practice.

In the special playback detection circuit in Fig. 1, the video signal specially played back from the laser vision video disk is selected depending on whether the vertical blanking period of the video signal appearing on the input terminal IN is expanded or contracted for each frame. Detect if there is.

That is, a part of the video signal appearing on the input terminal IN is supplied to the one input terminal of the subtraction circuit 12 as it is, and the remaining part is equivalent to one frame in the one-frame delay circuit 11 composed of a frame memory. After being delayed by the time, the signal is supplied to the other input terminal of the subtraction circuit 12. Therefore,
The subtraction circuit 12 outputs a difference signal between adjacent frames.

Here, as shown in the waveform (A) of FIG. 3, the input terminal IN
It is assumed that a horizontal sync signal of a video signal specially reproduced from a laser vision video disk or a vertical sync signal within a vertical blanking period (which may include an equivalent pulse) is appearing above. In this case, the waveform (A) is directly supplied to one input terminal of the subtraction circuit 12. At the same time, as shown in the waveform (B) of FIG. 3, the other input terminal of the subtraction circuit 12 is supplied with the horizontal synchronizing signal or the vertical synchronizing signal of one frame before. (B)
And are shifted from each other by 140 nsec. As a result,
As shown in the waveform (C), the subtraction circuit 12 outputs a difference signal string having a width of 140 nsec at each of the rising and falling edge portions of the horizontal synchronizing signal or the vertical synchronizing signal and having the polarity alternately inverted. To be done. This difference signal train is converted into a non-polar difference signal train as shown by the waveform (D) in the absolute value circuit 21 and supplied to the gate circuit 22.

The gate circuit 22 operates in synchronization with a gate pulse generated from horizontal and vertical sync signals, and selectively passes the output of the absolute value circuit 21 for a predetermined period in which the horizontal sync signal and the vertical sync signal appear. The absolute value of each difference signal that has passed through the gate circuit 22 is integrated in the integrating circuit 23. The comparison circuit 24 compares the integrated value of the absolute values of the difference signals output from the integration circuit 23 with a predetermined reference value determined by the relationship with the operation period of the gate circuit 22, and the integrated value exceeds the reference value. If so, a detection signal indicating that the video signal appearing at the input terminal IN is a video signal specially reproduced from the laser vision video disk is output to the output terminal OUT.

In contrast, the video signal appearing on the input terminal IN is NTSC
If it is a normal reproduction signal from a standard signal or a laser vision video disc that can perform the same processing as this, the horizontal sync signal and the vertical sync signal are output at almost the same time in adjacent frames, so they pass through the gate circuit 22. The non-polar difference signal sequence is only the component based on noise, and the integrated value is less than the reference value.

It should be noted that, from the subtraction circuit 12 of the motion detection circuit that uses the inter-frame correlation of the NTSC standard signal, during the appearance period of the composite video signal excluding the vertical blanking period, the color signal whose phase is inverted between adjacent frames An adjacent frame difference signal between the adjacent frame addition value and the luminance signal is output. The inter-frame added value of the color signals included in the output of the subtraction circuit 12 is removed by the low-pass filtering circuit 13, and only the difference signal ΔY of the luminance signal is supplied to the coring circuit 15 via the absolute value circuit 14. . On the other hand, the addition circuit 16 outputs + Y as the difference signal between adjacent frames of the color signal and the addition signal between adjacent frames of the luminance signal. The signal mainly composed of this luminance signal is a differentiating circuit.
A signal indicating the size of the edge existing on each line is supplied by 17 and supplied to the coring circuit 15 via the absolute value circuit 18.

The coring circuit 15 sets a refractory area which is expanded with the increase of the edge indicated by the output of the absolute value circuit 18 for the inter-frame luminance difference signal 1ΔY1 output from the absolute value circuit 14. The coring circuit 15 prevents the motion in the still image from being erroneously recognized as the edge fluctuates due to the jitter. The output of the coring circuit 19 is converted into a predetermined coefficient in the coefficient generating circuit 19 composed of a ROM or the like, and is output as an output terminal O as a signal indicating the magnitude of motion.
Is supplied to various motion-adaptive image quality improvement processing systems (not shown).

The motion detection circuit using the inter-frame difference signal may have a configuration different from that illustrated in FIG. 1 as long as it has a frame delay circuit shared with the trick play detection circuit.

The configuration has been illustrated above in which the absolute value of the inter-frame difference signal is created and integrated over the appearance period of both the horizontal synchronization signal and the vertical synchronization signal, but only the output period of either the horizontal synchronization signal or the vertical synchronization signal is shown. The absolute value of the inter-frame difference signal may be integrated and compared with a predetermined value.

(Effects of the Invention) As described in detail above, the special reproduction detection circuit of the present invention detects that the integrated value of the absolute values of the inter-frame difference signals within the output period of the horizontal and vertical synchronization signals exceeds a predetermined value. Since it is a configuration that detects that it is a special reproduction signal from a laser vision video disk, the special reproduction signal that closely resembles the NTSC standard signal can be highly accurate even if the vertical blanking period is slightly expanded or contracted for each adjacent frame. The effect that can be detected by.

Further, the trick play detection circuit of the present invention has a configuration in which the 1-frame delay circuit, which occupies most of the hardware amount, is also used as the motion detection circuit utilizing the inter-frame correlation of the NTSC standard signal, and therefore, the extremely small amount of hardware is required. There is an advantage that a special reproduction detection circuit can be realized based on the quantity.

[Brief description of drawings]

FIG. 1 shows the structure of a special reproduction detection circuit of a video disk according to an embodiment of the present invention, and the structure of a motion detection circuit utilizing inter-frame correlation of a TNSC standard signal which shares a 1-frame delay circuit with the special reproduction detection circuit. Together with the block diagram, FIG. 2 is a conceptual diagram for explaining the characteristics of the special reproduction signal from the laser vision type video disk to be detected in FIG. 1, and FIG. 3 is each part in the circuit of FIG. It is a waveform diagram which illustrates the waveform of. 1N: video signal input terminal, 11: 1 frame delay circuit, 12: subtraction circuit, 21: absolute value circuit, 22: gate circuit, 23: integration circuit, 24: comparison circuit, OUT ... … Special playback detection signal output terminal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinori Shimogura, 3-5-24 Miyahara, Yodogawa-ku, Osaka City, Osaka Prefecture NEC Home Electronics Co., Ltd. (56) Reference JP-A-61-234189 (JP, A) ) JP 63-126386 (JP, A) JP 63-1284 (JP, A) JP 64-84983 (JP, A)

Claims (1)

[Claims] 1. A frame delay circuit for delaying a video signal by one frame, which is shared with a motion detection circuit for detecting a motion in a display screen based on interframe correlation, and the video signal. Of the absolute value of the difference signal on the input terminal of the frame delay circuit is calculated over the appearance period of the horizontal synchronizing signal or the vertical synchronizing signal or both of them, and if the integrated value exceeds a predetermined value, A special reproduction detection circuit for a video disc, comprising: a calculation means for outputting a detection signal indicating that the video signal is a non-standard signal specially reproduced from a laser vision video disc.