JPH0216888A - Motion detection circuit - Google Patents

Abstract

PURPOSE:To prevent a TV signal from being misjudged to be motion in a weak electric field by changing a reference level in conformity with the jitter quantity of a synchronous signal, and simultaneously, suppressing the reference level in conformity with the noise of the motion of the signalless part of the synchronous signal in the comparison of a frame difference detection signal. CONSTITUTION:A differential between a luminance signal delayed by one frame by a frame memory 102 and the luminance signal is detected as a motion signal by a frame difference detection circuit 103, and the synchronous signal in an input signal is detected by a synchronous signal detection circuit 104, and the timing signal of an edge part where the synchronous signal changes is outputted, and the jitter quantity is detected through a switching circuit 105, and integrated by a synchronizing part integration circuit 106, and becomes the reference level corresponding to the jitter quantity, and is supplied to a comparator 111. On the other hand, a comparison control input to suppress the reference level is supplied to the circuit 111 through the switch circuit 107 and a signalless part integration circuit 108 by a signalless part timing signal outputted from the circuit 104. Thus, misjudgment to take the TV signal as the motion in the weak electric field is prevented, and a still picture is processed as it is.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a digital TV receiver or a digital VTR.
In particular, the present invention relates to a motion detection circuit required when performing three-dimensional processing between frames or between fields.

[Conventional technology]

Conventionally, as a device for completely separating luminance signals and color signals from NTSC video signals, there has been a device called high-definition TV (IDTV) that utilizes inter-frame or inter-field correlation of images. This method takes advantage of the fact that the NTSC signal is sent with the color phase inverted between frames. For still images, it uses the correlation between frames to achieve complete YC separation, and for moving images, it achieves complete YC separation. Since there is no correlation between frames, VC separation was performed within the field. This switching is performed by a motion detection circuit that detects the difference in brightness signals between frames, and when the value is constant and exceeds a bell, the mode is set to moving image, and when the value is below a certain level, the mode is set to still image mode.

FIG. 3 is a block diagram of a conventional example of a motion detection circuit. An input signal 31, which is an input video signal digitized by A/D conversion, is delayed by one frame by a frame memory 32. The NTSC signal consists of a complete picture of two fields, or 525 frame scan lines. Therefore, if the still image is delayed by one frame, the same luminance signal as the input signal can be obtained. The frame difference detection circuit 33 is a circuit that detects the difference between the luminance signal of this input signal 3] and a signal delayed by 1° frame from the frame memory 32, and the output from this is outputted as an interframe motion signal. This motion signal is compared with a preset comparison level 34 in a comparison circuit 35, and is binarized and output as a detection output 36.

The circuit shown in Fig. 3 is applied to an NTSC video signal as a standard signal in which there is a correlation between the color subcarrier and the horizontal synchronization signal. FIG. 2 is a block diagram of a conventional example that can also handle a non-standard signal, which is a video signal with no correlation between a carrier wave and a horizontal synchronization signal. In this example, it is intended to determine whether the input signal 41 is a standard signal or a non-standard signal based on the frame difference output of the synchronization signal portion that is always output. The frame memory 42 and frame difference detection circuit 43 operate in the same manner as shown in FIG. If it is a standard signal, the frame difference in the sync signal part will always be 0 and will not be output.On the other hand, if it is a non-standard signal, note that the phase is not constant between frames, so a frame difference will occur in the sync signal part. , synchronous signal partial time 1?844
This output is integrated for a certain period of time by the switch circuit 1i'1.5 and the integrating circuit 46, and the comparison level 47 of the motion signal is controlled according to this integrated value, and the comparison circuit 48 compares and outputs the detected output /'I9. get.

[Problem to be solved by the invention]

The conventional motion detection circuit shown in FIG.
When a signal other than the signal is input, the correlation between the frames and the luminance signal disappears, so it seems that the mode is always in the motion mode. However, in reality, there are regular NTSC signals and other video signals (VTR signals, computer signals, etc.)
In many cases, the correlation between the frames and the luminance signals does not necessarily differ significantly, resulting in extremely ambiguous operations such as switching to moving image mode or switching to still image mode.

In addition, as shown in Fig. 4, when the frame difference signal of only the synchronization signal part is detected and the comparison level of the motion detection signal is changed according to this amount, it is difficult to detect the area where the electric field of TV broadcasting is weak. In regional areas, the effectiveness of this IDTV system was low because noise was generated in the frame difference output of the synchronization signal, and even a slight deterioration in the electric field strength was immediately recognized as a non-standard signal and the system was switched to video mode.

[Means to solve the problem]

The motion detection circuit of the present invention includes a frame memory that delays an input signal obtained by converting a video signal into a digital signal by that frame, and outputs the difference in luminance signal between the input signal and the output of the frame memory as a motion signal. a frame difference detection circuit for detecting a frame difference, and a first timing signal of an edge signal portion before and after the synchronization signal changes from the input signal;
and a synchronization signal detection circuit that outputs a second timing signal of a non-signal portion where the synchronization signal does not change;
A synchronous part integrating means extracts and integrates the motion signal according to a timing signal, a no-signal part integrating means extracts and integrates the motion signal according to the second timing signal, and compares the outputs of the synchronous part integrating means with the motion signal. and a comparison circuit that controls the comparison level by the output of the no-signal portion integration means and outputs a binary detection output.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the motion detection circuit of the present invention. The present invention adds a synchronous signal detection circuit 104 for detecting a synchronous signal and a switch circuit 1.0 to the conventional circuit shown in FIG.
5, 1.07 and synchronous part integrating circuit 106. A no-signal portion detection circuit 108 is provided to vary the comparison level according to the amount of jitter.

An input signal 101, which is an input video signal digitized by A/D conversion, is delayed by a frame by a frame memory 102. The frame difference detection circuit 103 is a circuit that detects the difference between the luminance signal of this input signal 101 and a signal delayed by one frame from the frame memory, and the output from this is output as a motion signal between frames. on the other hand,
A synchronization signal detection circuit 10/l that detects only the synchronization signal part from the input signal 101 detects the horizontal or vertical timing signal of the edge signal part, which is the timing before and after the synchronization signal changes, during the period of the horizontal or vertical synchronization signal. A timing signal is created for a portion where the synchronization signal does not change during the period of the synchronization signal, that is, a no-signal portion.

First, the output signal of the frame difference detection circuit 103 is transferred to the switch circuit 105 by the timing signal of the edge signal portion.
The synchronization section integrating circuit 106 integrates the motion signal of the edge portion of the synchronization signal, that is, the shift between frames of the synchronization signal, over several fields. NTSC
In a regular video signal, the synchronizing signal part does not contain video information whether it is a moving screen or a still screen, so the signals between frames always match, and the frame difference detection circuit 103 The value of the output is "0". However, in a signal containing jitter, such as a VTR signal, regardless of whether the luminance signal changes over time, the output delayed by one frame will not necessarily match the synchronization signal. This is because the one-frame time delay used here is created using an extremely precise clock source controlled by a crystal.
For example, if the clock source is chosen to be 4 times the color subcarrier signal, this clock will be 14.31818 MHz.
Using this clock, the output delayed by 477750 clocks becomes the output delayed by one frame.

However, signals from VTRs, etc. do not use locking to control the output phase, so they suffer from "jitter".
In this way, the time of one frame always changes. In this way, non-standard signals can be determined by detecting the motion signal of the edge portion of the synchronization signal, but since the value will fluctuate due to slight noise etc. Integrate over the 2 frames.

On the other hand, in the circuits 102 to 104, 106, 111,
When a standard NTSC signal, that is, a TV broadcast signal, is input with a weak electric field, a motion signal is output at the edge of the synchronization signal, which should not be output. However, even in a weak electric field, it is preferable to process a still image as a still image; because of the weak electric field, it is not preferable to treat it as a non-standard signal and perform the same processing (in-field processing) as a moving image. This is because even in a weak electric field, the image quality on the screen is no different from that in a strong electric field. Therefore, do not add a circuit for detecting weak electric fields as described below.

The output signal 3 of the frame difference detection circuit 103 is extracted by the switch circuit 1.07 according to the timing signal of the no-signal part of the synchronization signal from the synchronization signal detection circuit 1.04, and the no-signal part of the synchronization signal is extracted by the no-signal part integration circuit 108. was integrated, and the comparative suppression level was determined by Hisakata.

In this way, the motion output from the frame difference detection circuit,
Comparison level 1, which is the output of the synchronous part integrating circuit 1.06
09 is compared by comparison circuit 1]1 and binarized,
The comparison control input which is the output from the no-signal portion integration circuit 108], ], and the comparison level suppressed by O is defined as the detection output]12. As a result, for signals with time fluctuations such as VTR signals, the comparison level human power 109 can be reduced to 0.
” to make it easier to move in the direction of movement.On the other hand,
Noisy signal due to weak electric field even with regular NTSC signal input1
This is detected for the signal 〇-, and the comparison level 109 is controlled to be raised by the input 110 to prevent it from being erroneously determined as a moving signal.

FIG. 2 is a block diagram of an adaptive YC separator used in IDTV, using the motion detection circuit of the present invention. This is an example of a circuit that uses the motion detection circuit 208 of the present invention to separate a Y signal (luminance signal) and a C signal (chrominance signal) from an input composite video signal.

This circuit includes an A/D converter 202, YC separation circuits 203 and 206, and a line memory 204. ．． 205, frame memory 207, motion detection circuit 208, switching circuit 209, Y signal processing circuit 2]0, C signal processing circuit 2]1, and D/A converter 212.2.14. has been done.

If the signal has movement, it is detected by the movement detection circuit 208 and sent to the line memory 204 . ．． A switching circuit 209 selects the YC separated output processed within the field by the YC separation circuit 203 using the YC separation circuit 205 . For the signal of the still image portion, a switching circuit 209 selects a YC separated output subjected to frame processing by a YC separating circuit 206 using a frame memory 207 .

The Y signal not output from the switching circuit 209 is sent to the Y signal processing circuit 210. The Y signal 213 passes through the D/A converter 2]2, and the C signal is sent to the C signal processing circuit 2]1.

It becomes a C signal 215 through the D/A converter 2]4.

For a jittery signal such as a VTR signal, the output of the motion detection circuit 208 detects a shift in the synchronization signal part, making it easier to select intra-field YC separation using line memory. When inputting a certain standard NTSC signal, there is an advantage that it can be determined that the signal is a standard signal, and the selection of YC separation similar to that of an input signal without strong electric field noise can be realized.

〔Effect of the invention〕

As explained above, the present invention detects the amount of jitter in the synchronization signal and changes the comparison level according to this level, and at the same time detects the amount of jitter in the synchronization signal and changes the comparison level in accordance with this level, when comparing frame difference detection signals using a frame memory. By detecting the noise component of the movement and suppressing the comparison level by this level,
This eliminates the conventional drawback of determining TV signals as motion due to weak electric fields, and has the effect of outputting extremely natural motion signals.

210...Y signal processing circuit, 211...C signal processing circuit, 212, 214...D/A converter, 213...
・Y signal, 215...C signal.

Claims (1)

[Claims] The first input signal is a video signal converted into a digital signal.
a frame memory that delays by a frame amount; a frame difference detection circuit that outputs a difference in luminance signal between the input signal and the output of the frame memory as a motion signal; and edges before and after the synchronization signal changes from the input signal. a synchronization signal detection circuit that outputs a first timing signal of a signal portion and a second timing signal of a non-signal portion in which the synchronization signal does not change; and a synchronization portion integrating means that extracts and integrates the motion signal using the first timing signal. and a no-signal part integrating means for extracting and integrating the motion signal according to the second timing signal, and comparing the motion signal with the output of the synchronous part integrating means as a comparison level, and using the output of the no-signal part integrating means to integrate the motion signal. A motion detection circuit comprising: a comparison circuit that controls a comparison level and outputs a binary detection output.