JPS6239992A - Moving part detecting circuit - Google Patents

Abstract

PURPOSE:To prevent an animation which should be reproduced from being reproduced as a still picture even when a movement compensation is performed by using a differential signal DE1 in pseudo one frame. CONSTITUTION:A differential signal DE2 between two frames outputted from an absolute value detecting circuit 26 is maintained in a memory 29 for one frame period and thereafter, multiplied by (a) (0<a<1) with a multiplication circuit 30 and inputted to a selecting circuit 28. The selecting circuit 28 compares the largeness of levels of a differential signal DE2F0 between two frames of a present frame F0 outputted from the absolute value detecting circuit 26 and said input signal and outputs the larger one. By repeating the above- mentioned operations, from a temporal filter 27, a signal S0 in which a high level component is interpolated in a part X is obtained. The obtained output signal S0 of the temporal filter 27 is applied to a selecting circuit 45 and used for the gate of a differential signal DE1 in pseudo one frame which is auxiliarily used. Thereby the animation which should be reproduced is prevented from being reproduced as the still picture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a motion part detection circuit in a television broadcasting system that compresses and transmits a television signal band according to an offset subsampling method.

[Technical Background of the Invention] In recent years, high-definition television systems have been developed that aim to improve image quality by increasing the density of information. The band of the television signal handled by this system is very wide, and it is necessary to compress the band when transmitting it.

As a compression method for the transmission band of a television signal, for example, there is an offset subsampling method.

In this method, for the sampling phase set as shown in Fig. 5, in a certain frame (hereinafter referred to as the first frame), sampling data of the phase specified by the rOJ mark is transmitted, and the next frame is In the frame (hereinafter referred to as the second frame), sampling data of a phase defined by a 10'' mark is transmitted.

FIG. 6 is a circuit diagram showing the configuration of a television receiver that receives television signals transmitted according to such an offset subsampling method.

First, the received television signal RD is sent to the signal separation circuit 11
and is separated into a video signal V, a motion correction signal M, a block control signal B, an audio signal S, and a control signal C, respectively.

The video signal V, which is the signal of the current frame FO, is supplied to a moving image signal processing circuit 13 and a switching circuit 14, which will be described later. In addition to the signal of the previous current frame FO, the switching circuit 14 is guided by the signal of the frame F1 171 nodes before, which is output from the image memory circuit 15, and the signal of the frame "2", two frames before. 14 replaces the signal of the frame F2 two frames before with the signal of the current frame FO, thereby transmitting the signal of the ring frame FO and the signal of the frame F1 one frame before.

The signals of these frames FO and F1 are processed by the still image signal processing circuit 12. The signal is supplied to each of the image memory circuit 15 and the moving portion detection circuit 16.

The image memory circuit 15 is basically a memory whose capacity is equivalent to one frame, and the image memory circuit 15 is a memory whose capacity is equivalent to one frame.

The signal of Fl is input, and the previous frame F
The signal of frame 1 and the signal of frame 2 two frames before are output.
The signals of 1 and F2 are led to the moving part detection circuit 16, and the signals of the above-mentioned frame FO.

It is used together with the Fl signal when detecting a moving part, which will be described in detail later.

Now, in the receiver shown in FIG. 7 which processes offset sub-sampling television signals, the signal processing methods are different for still images and moving images. That is, the still image signal processing circuit 12 uses both the signal of the current frame FO and the signal of the frame F1 one frame before, and superimposes them in a continuous manner as shown in FIG. 5 to form a frame image. .

On the other hand, in reproducing a moving image, if past sampling data is used, a double image will result, so the moving image signal processing circuit 13 performs image processing using only the sampling data of the ring frame FO. In this case, data interpolation is performed using an interpolation filter to compensate for missing data.

In this way, the two types of video signals vs and vm obtained according to the still image system and the moving image system, respectively, are appropriately processed in the mixing circuit 17 according to the output signal [)m of the moving part detection circuit 16 that detects the moving part of the image. The signals are mixed to become a video signal VO for actual image reproduction.

Note that when processing images obtained when a TV camera pans slowly, even if the subject is a stationary object, the image that appears on the screen is changing, so it is processed as a moving image. As mentioned above, video processing uses only the sampling data of the current frame FO, and the resolution deteriorates compared to still image processing.Therefore, by performing the following motion correction, the above resolution deterioration can be prevented. There is.

Motion correction is performed by controlling the amount of delay of the image memory circuit 15 in accordance with the motion correction signal M obtained from the signal separation circuit 11. The motion correction signal M is a signal indicating the amount and direction of movement of a stationary object within the screen, and is inserted into the television signal RD in advance. The image memory circuit 15 shifts and reads out the previous frame signal corresponding to the movement of the screen according to the motion correction signal M.Thereby, even during panning, images of past sample points and current sample points are superimposed, It is possible to process it as a still image and maintain the resolution.

Now, to detect the moving part of the image, frame FO,
What is necessary is to take the difference in sampling data between F1. But these two frames FO.

Since the sampling phase differs between F1, a pseudo difference signal (hereinafter referred to as a pseudo 1-frame difference signal) is generated.
You can only get DEL. This pseudo one-frame difference signal reliably detects a moving part (moving object) in an image as motion, but depending on the image content, even a still image may be detected as a moving image.

Such a problem can be solved by calculating the difference between frames FO and F2 having the same sampling phase. However, in this case, since movement between one frame cannot be detected, a new problem arises in that what should be reproduced as a moving image is reproduced as a still image.

The above-mentioned problem will be explained using FIG. 7. The figure (a) is sampling data showing the position of an object moving at a constant speed (hereinafter referred to as a moving object) on the screen at one frame interval. The figure (b) is the ideal moving part detection signal ( The ideal one-frame difference signal) Dn+i is shown in the same figure (C
) is frame F○.

The two-frame difference signal DE2FO for each of Fl,
DE2F1 is shown. Difference signal DE2FO is frame FO
, F2, and the difference signal DE2F1
is frame F1. This is the difference signal DE2 between F3. In these differential signals [)mi, DE2FO, and DE2F1, the high level component corresponds to reproduction of a moving image, and the low level component corresponds to reproduction of a still image.

Here, the difference signal D between two frames corresponding to the current frame FO
Comparing E2FO and the ideal moving portion detection signal Dm1, in the former, the portion X corresponding to the moving object position in frame F1 is at a low level. Therefore, in this portion X, a still image is reproduced. As a result, even though the image of part X is originally a moving image, there are two frames FO.

Since it is constructed using sampling data of Fl, 2
This results in a heavy image.

Therefore, when the two-frame difference signal DE2 is used, it is necessary to interpolate the missing high-level component of the portion X. In principle, this interpolation is performed by temporally stretching the two-frame difference signal DE2FO corresponding to the current 71-norm FO and the two-frame difference signal DE2F1 corresponding to the frame F1 one frame before. be exposed. FIG. 7(d) shows a difference signal in which a high-level component is inserted into the portion X, and by detecting a moving portion using this, it is possible to prevent the occurrence of double images.

In this way, by interpolating the two-frame difference signal DE2, in principle, the two-frame difference signal DE
It is possible to obtain a moving part detection signal using only 2. However, in the currently considered moving part detection processing, the difference signal DE2 between two frames is used for moving part detection.
There are many configurations in which the pseudo one-frame difference signal DE1 is used together. In this case, whether or not the pseudo one-frame difference signal can be used is determined according to the interpolated output of the two-frame difference signal DE1. Therefore, even with such a configuration -〇-, it can be said that in principle, the detection of a moving part is performed according to the difference signal between two frames, and the pseudo one-frame difference signal DE1 is used auxiliary. It's just being told.

In this way, according to the configuration in which the pseudo one-frame difference signal DE1 is used auxiliarily, the problem that a still image is detected as a moving image when only the pseudo one-frame difference signal DE1 is used to detect a moving part can be solved. Almost never occurs.

The moving part detection circuit 16 shown in FIG. 6 is configured to use the pseudo one-frame difference signal DE1 complementary and dynamically to detect moving parts. In this case, the moving part detection circuit 16 not only determines whether or not the pseudo one-frame difference signal DE1 can be used based on the interpolation of the two-frame difference signal DE2, but also uses the block control signal given from the signal separation circuit 11. It is also determined by B. This block control signal B is a pseudo one-frame difference signal DE
This is a signal sent from the transmitting side as a signal indicating whether or not 1 can be used. That is, on the transmitting side, the screen is divided into several hundred blocks, each block is judged as a moving image or a still image, and the result of this judgment is sent to the receiving side as block control signal B.

In this way, by determining whether or not to use the pseudo 1-frame difference signal rlF1 based on the two signals, the block control signal B and the interpolated output of the 2-frame difference signal DF2, the pseudo 1-frame difference signal rlF1 can be used. It is possible to prevent a portion erroneously detected as a moving image by DE1 from being subjected to moving image processing with a high probability.

[Problems with the Background Art] As explained above, conventionally, in principle, the portion that should be reproduced in a moving image is reproduced in a still image using the two-frame difference signal DE2 corresponding to the two frames FO and F1. It prevents you from being

However, even with such a configuration, the above problem cannot be solved when, for example, the camera is panned to follow a moving object.

In other words, a moving object moving at a constant speed is now shown in Figure 8 (
As shown in a), always fix it at a predetermined position on the screen:
Let's consider the case of panning the camera. In addition,
Here, let us consider the scanning lines indicated by broken lines.

Frame F1. read out from the image memory circuit 15 by motion correction. The lean pulling data of F2 and the current frame FO are as shown in FIG. 8(b). Note that (b) in the same figure assumes that the moving object moves to the right on the screen (in this case, due to the above-mentioned motion correction, the sampling data of frame "1" is shifted from 1 to the left when viewed on the screen). In this case, the ideal moving part detection signal Dmi and the difference signal DE between two frames between the current frame and one frame before
2FO and DE2F1 are shown in FIGS. 2(c) and 2(d), respectively.

As is clear from FIG. 9(d), when panning is performed by following a moving object, the position of the moving object is always fixed at a predetermined position from the past to the current frame. The difference signal DE2FO between two frames for
Both DE2F1 end up being equal. Therefore, it becomes impossible to interpolate the high-level missing portion X using both signals DE2FO and DE2F1, and a double image will be reproduced in this portion X.

[Objective of the Invention] The present invention has been made to address the above-mentioned circumstances, and has an object to prevent parts that should be recirculated as a moving image from being reproduced as a still image even when motion compensation is performed. The purpose of this invention is to provide a moving part detection circuit that can perform the following steps.

[Summary of the Invention] The present invention replaces the high-level missing portion of the two-frame difference signal DE2FO with respect to the current frame FO with the previous frame FO.
A signal for detecting a moving part is obtained by interpolating the two-frame difference signal DE2F1 relative to 1 with a temporally expanded signal, and a pseudo one-frame difference signal is gated by OR outputting this detection signal and a motion correction signal. The moving portion detection signal [)m is obtained by sequentially selecting the one having a higher level between this gate output and the detection signal.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention.

The circuit shown in FIG. 1 is configured to use both a two-frame difference signal and a pseudo one-frame difference signal to detect a moving part.

First, a moving part detection operation when no motion correction is performed will be described.

In FIG. 1, the terminal 21 has a frame FO.

A signal constituted by Fl is given to the terminal 22,
Frame F1. A signal constructed by F2 is provided. These two signals are each passed through a low pass filter LP.
After high frequency components are removed at F23.24, the subtraction circuit 25
Subtraction processing is performed. As a result, the difference signal DE2 between two frames is obtained, and its absolute value is sent to the absolute value detection circuit B52.
It is taken at 6. The output signal of this absolute value detection circuit 26 is
The signal is input to the temporal filter 27.

This temporal filter 27 is for interpolating the missing high-level component in the portion X explained in FIG. The operation of this temporal filter will be explained with reference to FIG. Similar to FIG. 7, FIG. 2 assumes an object moving at a constant speed on the screen, and shows the output signal So of the temporal filter LL in this case.

In the first frame, the two-frame difference signal DE2 output from the absolute value detection circuit 2G passes through the selection circuit 28 as it is and is stored in the memory 29. After being held in this memory 29 for one frame period, it is multiplied by a (Q<a<1) in a multiplier circuit 30 and sent to a selection circuit 29.
8 is input. The selection circuit 28 compares the levels of this input signal and the two-frame difference signal DE2FO of the current frame FO output from the absolute value detection circuit 26, and outputs the larger one.

By repeating the above operations, the temporal filter (2) outputs 1q of the signal So with the high level component interpolated in the portion X, as shown in FIG. 2(d).

In the temporal filter, 31 and 32 are circuits for generating write address data and read address data for the memory 29, respectively. These address generation circuits 31 and 32 output address data in synchronization with the frame period of the received signal. Further, the switching circuit 33 alternatively selects the two atto1nos data during the data write period and the data read period of the memory 29.

The temporal filter output signal So obtained in this way is given to the selection circuit 45 and is used to gate the pseudo one-frame difference signal DEI used auxiliary.

Here, to explain the generation of the pseudo one-frame difference signal DEI, the sub-sample switch circuit 35 extracts sampled data of the current frame "0" from the input J signal at the terminal 21 and supplies it to the interpolation filter 36. Assuming that the current frame FO is the first frame as shown in FIG. 3, the interpolation filter 36 interpolates data corresponding to the sampling position of the second frame from the input signal A, and
A signal corresponding to the sampling position as shown in the figure is obtained. This is applied to the subtraction circuit 37 and the low pass filter 23
By performing subtraction processing with the output of , a pseudo one-frame difference signal DE1 is obtained.

Pseudo one-frame difference signal DE obtained in this way
After the absolute value of I is determined by the absolute value detection circuit 38, it is applied to the gate circuit 29. This gate circuit 39 applies an input signal DE1 to a subsequent gate circuit 41 in the case of a moving image according to a block control signal B applied to a terminal 40.
In the case of a still image, its supply is stopped. Gate circuit 41
The input signal is the gate signal S. is gated by and applied to the selection circuit 34. The selection circuit 34 sequentially selects the one with a higher level among the two human force signals and outputs it as a moving part detection signal [)m.

The above gate signal S. is obtained by slicing the output signal So of the temporal filter 27 at a predetermined slice level L1 by the comparator 42, and the OR circuit 4
3 to the gate circuit 41.

In this way, the pseudo 1-frame difference signal DE1 is output as the moving part detection signal Q-m when the use of the pseudo 1-frame difference signal DE1 is permitted by the block control signal port.■ Temporal When the following three conditions are satisfied: When the level of the output signal SO of the filter ■ exceeds the slice level level 1 ■ When the level of the pseudo one-frame difference signal DE1 is higher than the level of the output signal So of the temporal filter 27 be. therefore,
In FIG. 1, it can be said that the two-frame difference signal DE2 is mainly used to detect a moving part, and the pseudo one-frame difference signal DEI is used auxiliary.

Next, the motion part detection operation during motion correction, which is a feature of the present invention, will be explained.

When performing panning that follows a moving object as described earlier during motion correction, the output signal S of the temporal filter ■
From o, the high level component is missing in part X for the reason explained in No. 1 with reference to FIG. 8 above. Furthermore, it is not possible to generate a gate signal for use with the pseudo one-frame difference signal DE1.

Therefore, in FIG. 1, the gate signal So is combined with the output signal SO of the temporal filter 27 and the motion compensation signal M.
It is obtained as the logical sum output.

That is, the motion correction signal M applied to the terminal 44 has its absolute value taken by the absolute value detection circuit 45 and is applied to the comparator 46. In this comparator 46,
The level is compared with a predetermined slice level L2, and only when it is higher than this level L2, the comparator 46 outputs it as a gate signal. The gate signal obtained from the motion correction signal M and the gate signal obtained from the comparator 42 according to the output signal So of the temporal filter are logically summed in an OR circuit 43 and given to the gate circuit 41 as the gate signal SG. .

In this way, the pseudo one-frame difference signal DE1 is gated not only by the output signal So of the temporal filter 27 but also by the motion compensation signal M, so that even during motion compensation, the video processing should be performed. It is possible to interpolate the missing high-level component in portion x. That is, along with the motion correction, the output signal S of the temporal filter 27
[Even if the high level component is missing in the portion X from +, the motion compensation signal M is applied to the terminal 44 during this motion compensation. Therefore, if the amount of motion correction is large and the missing high-level component in portion X is not interpolated, 2
If the superimposed image poses a visual problem, the level of the motion correction signal M exceeds the slice level L2, and the comparator 46 outputs a gate signal. As a result, in the portion X, the pseudo one-frame difference signal DE
1 will pass through the gate circuit 41. By selecting this passed output by the selection circuit 34, the missing high-level component in the portion X is interpolated at the stage of the moving portion detection signal 1)m. In Naginara, the purpose of the pseudo one-frame difference signal DF1 is to ensure that moving portions of the image are detected as motion. In this case as well, there is a problem with the pseudo one-frame difference signal DE1, that is, even if it is a still image, it is detected as a moving image. Since the interception difference signal DE1 is controlled to pass through 1, the pseudo 1-frame difference signal DE1 is inserted into the unnecessary part.
1 is never used.

From the above, according to this embodiment, even during motion correction,
Part X that should be processed in the video is processed as a still image 2
It is possible to reliably prevent the occurrence of overlapping images.

[Effects of the Invention] As explained above, according to the motion part detection circuit of the present invention, by appropriately using a pseudo one-frame difference signal during motion correction, even during motion correction, it is possible to detect a moving image. It is possible to prevent parts that should be reproduced in still images from being reproduced in still images.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG.
Figures 4 to 4 are diagrams for explaining the operation of Figure 1, Figure 5
The figure is a diagram to explain the offset subsampling method.
FIG. 6 is a circuit diagram showing the configuration of an offset sub-sampling type television receiver, and FIGS. 7 and 8 are diagrams for explaining a conventional moving part detection operation. 21.22.40.44... terminal, 23.24...
Low pass filter, 25.37... Subtraction circuit, 26°38.45... Absolute value detection circuit, 27... Temporal filter, 35... Sub sample switch circuit,
36... Interpolation filter, 39.41... Gate circuit, 42.46... Coverator, 43... OR circuit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 ○ ○ ○ ○ Figure 3 Figure 4

Claims (1)

[Claims] a first difference detection means for detecting a two-frame difference signal indicating a difference between a first frame signal of a television signal transmitted according to the offset subsampling method and a second frame signal two frames before the first frame signal; By substantially adding the first two-frame difference signal sequentially supplied by the difference detection means and the previous second two-frame difference signal, the difference signal is removed from the first two-frame difference signal. interpolating means for interpolating difference information between the first frame signal and a third frame signal one frame before the first frame signal with respect to the first two-frame difference signal and outputting the interpolated signal as a motion detection signal; a second difference detection means for detecting a pseudo one-frame difference signal indicating a difference between the first frame signal and the third frame signal; and an image of the first frame signal and the third frame signal. a determining means for determining the presence or absence of a motion correction signal indicating a content deviation; a gate signal generating means for calculating a logical sum between an output of the determining means and a motion detection signal output from the interpolating means and outputting a gate signal; a gate means for gating the pseudo one-frame difference signal using a gate signal; and a selection means for comparing the output signal of the gate means with the motion detection signal and successively outputting the larger signal as a motion portion detection signal. A moving part detection circuit characterized by comprising: