JPS62145984A - Motion detecting circuit - Google Patents

Abstract

PURPOSE:To accurately detect the time-coefficient of motion of a signal to be photographed by passing through a scanning-line interpolation signal and an inter-field differential signal obtained by supplying output signal from a memory to a subtracting circuit to a coefficient circuit. CONSTITUTION:A video signal for interlace scanning is supplied to a line memory 12 from an input terminal 11, and the output of the memory 12 and the said signal from the terminal 11 are added with each other by an adder 14. The gain of the output of the adder 14 is adjusted by a coefficient device 15 to generate an in-field interpolation scanning signal. Also, the output of the memory 12 is supplied to a memory 13, and the output of the memory 13 is made an inter-field inter-polation scanning signal. Meanwhile, the outputs of the device 15 and the memory 13 are supplied to a subtractor 20 to generate the inter-field differential signal. This signal is supplied to a low-pass filter 21 via and absolute value circuit 22, and the output of the circuit 22 is supplied to a motion-coefficient circuit 23. The circuit 23 varies the proportion between the gains of adders 16 and 17 so that two interpolation scanning signals are synthesized by an adder 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a motion detection circuit that detects motion information of a subject image reproduced by an incremental scanning television signal.

[Technical background of the invention and its problems] In interlace scanned television images, fine line drawings tend to flicker, so a method of interpolating the scanning lines and converting them into non-interlace scan television signals to display the image. is being developed. Scanning line interpolation methods include intrafield scanning line interpolation and interfield scanning line interpolation.

Intra-field scan line interpolation uses upper and lower scan lines to create a scan line between them, resulting in vertical frequency components of the image being band limited. Therefore, the resolution of still images tends to deteriorate. In addition, inter-field scanning line interpolation is effective for still images because it interpolates the current field image and the field image from 1/60 seconds ago to be displayed superimposed, but it has a high resolution for moving images with moving subjects. Not very good. If the subject moves, the moving parts will look like edges or comb teeth.

As mentioned above, if the interpolation method is not selected appropriately for still images and moving images, image quality will deteriorate.To improve this, we detect the movement of the subject and perform intra-field scanning line interpolation for the moving image. For still image parts, circuits that automatically perform scanning line interpolation between fields or frames are being considered.

FIG. 7 shows the state of scanning line interpolation using a time axis and a vertical axis, where white circles indicate interlaced scanning lines and black circles indicate interpolated scanning lines. When creating a scanning line at the position of a black circle, it is necessary to distinguish whether the subject is a still image or a moving image, and for this purpose an interframe difference signal is detected. The above-mentioned difference signal is obtained between the scanning lines indicated by double arrows, and if the difference is small, a still image is determined, and if it is large, a moving image is determined. If it is determined to be a still image, an interpolated scanning line is created using the scanning line from one field before, and if it is determined to be a moving image, an interpolated scanning line is created using the upper and lower scanning lines in the same field. It will be done.

However, with the above determination method, if the subject moves quickly up and down, the determination is not necessarily appropriate, and an unnecessary image that appears as a trail behind the subject remains as a display result. FIG. 8 shows a case where a black object consisting of three scanning lines moves quickly upward. Looking at area A, interpolated scan lines dB and d7 are scan lines all, a12 and a, respectively.
It is made by 12 and a13 (inside the field). This is because the difference between the differential signals of scanning lines a1 and all and a2 and a12 is large. Next, similarly in area C, interpolated scanning line d1. d2. d3 is created by Somoma in the field.

Coreha, between scanning lines c1 and el1, between c2 and c12, bl
This is because the difference signal between and bl1 is large. Next, area B
, the difference signals between scanning lines b2 and blZ and between b3 and bla are small. Therefore, interfield scanning line interpolation is performed, and the scanning line one field before is used, and the interpolated scanning line d4. d5 is created. However, since the scanning line one field before is a signal representing a black subject, the interpolated scanning line d4. d5 displays a black image and deteriorates the image quality.

In order to correct the above-mentioned problems, a circuit has been proposed that monitors the difference in signals across four fields to detect the movement of a subject and appropriately determines whether a moving image is a still image or not. There is. However, this circuit requires a memory for three fields, as disclosed in Japanese Patent Application Laid-open No. Sho GO-27287, so there is a problem that the scale of the circuit becomes very large.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a motion detection circuit that is small in circuit scale and does not cause deterioration in image quality even when processing moving images.

[Summary of the Invention] In order to achieve the above object, the present invention provides a memory having a capacity for one field of a television signal, as shown in FIG. The scanning line interpolation signal and the output signal of the memory are used to obtain an inter-field difference signal in a subtraction circuit, and the inter-field difference signal is passed through a coefficient circuit to obtain the object signal. This is designed to accurately detect the temporal [hyperactivity coefficient].

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a video signal for t-interlaced scanning is supplied to an input terminal 11, and is processed to obtain an interpolated scanning line signal, as well as a process for determining moving images and still images. receive. That is, the input terminal 11 is connected to a line memory 12, and a memory 13 is connected in series to this memory 12. Note that H in the figure means one horizontal period. Line memory 2 and memory 13 constitute one field's worth of memory. The circuit for generating the intra-field thin scanning line signal includes an adder 4 that adds the signal at the input terminal 11 and the signal at the output section of the field memory 14;
a coefficient unit 15 that adjusts the gain of the output of the adder 14;
The multiplier 16 controls the output of the coefficient multiplier 15 according to the ratio of moving images to still images. On the other hand, the circuit for generating the interfield interpolated scanning line signal utilizes the output signal of the memory 13 and includes a multiplier 17 that controls the gain of this signal. The intra-field scan line signal and the inter-field interpolation scan line signal are added according to the ratio of moving images to still images.
1B and is derived as a final scanning line interpolation signal.

Next, detection of the movement of the subject in the human video signal is performed as follows. That is, the inter-field difference signal is created by supplying an interpolated signal in which the vertical frequency component of the image is band-limited to remove noise, that is, the output of the coefficient unit 15 and the output of the memory 13 to the subtracter 20. . Subtractor 2
The differential signal from 0 is supplied to the absolute value circuit 22 via a low-pass filter 21 to prevent malfunctions due to high-frequency noise and to remove the influence of color subcarriers whose phase is reversed between frames, and the output of this circuit is It is supplied to the coefficient conversion circuit 23. The motion coefficient conversion circuit 23 includes, for example, a multiplier 16,
The gain coefficients of the multiplier 17 are (1-1?) and R, respectively.
Then, the coefficient R (0<R<1) is derived as R-1 for a moving image and R-0 for a still image. As a result, the multiplier 17 and the gain ratio of the multiplier 17 are varied.

The inter-field difference signal of the above circuit can be expressed as shown in FIG. 2 when viewed in terms of scanning lines. FIG. 2 shows scan lines on a time axis and a vertical axis, with white circles indicating interlaced scan lines and triangles indicating interpolated scan lines. The interpolated scanning line signal at the position indicated by the black circle is explained as follows. First, the scanning line signals 25a and 25
The intra-field inter-sleeve scanning line signal using b is derived from the coefficient unit 15. Also, the scanning line signal 25c of one field before
is obtained from the memory 13 as an inter-field interpolated scanning line signal. Here, the intra-field interpolation scanning line signal and the interfield interpolation scanning line signal are combined according to the proportion of still images and moving images, and an interpolation scanning line signal at the position indicated by a black circle is obtained.

Here, if the difference signal is large, it is a moving image, and if the difference signal is small, it is a still image.

As described above, in the present invention, since the inter-field difference signal is obtained using the intra-field inter-scanning line signal, it is possible to appropriately determine whether the image is a moving image or a still image, and it is possible to improve the quality of an image subjected to scanning line interpolation.

The means for obtaining the differential signal is not limited to the above embodiment, and as shown in FIG. 3, two scanning lines may be used. That is, intra-field scanning line supplementary signals are generated at the positions of the triangle marks, and inter-field difference signals are generated between the scanning lines indicated by arrows X1 and x2, respectively. This makes it possible to more accurately grasp the movement of the subject.

The circuit for performing the motion detection shown in FIG. 3 is constructed as shown in FIG. The same parts as in FIG. 1 are given the same reference numerals, and the parts different from the circuit in FIG. 1 will be explained. The output of the line memory 12 is supplied to a series circuit of a memory 13a for 26111 minutes and a memory 13b He for 111 minutes. The input and output of the line memory 13b are supplied to an adder 31, and the added output is passed through a coefficient unit 32 to a subtracter 35.
supplied to The output of the coefficient multiplier 32 is in the state of an intra-field interscanning signal. A subtracter 35 performs subtraction processing between the output of the coefficient unit 32 and the signal at the input terminal 11 to obtain an inter-field difference signal. Further, the input and output of the line memory 13c are added by an adder 33, and the added output is supplied to a subtracter 36 via a coefficient unit 34. This subtractor 3
6, subtraction processing is performed between the output of the coefficient unit 34 and the signal of the manual section of the memory 13a to obtain an inter-field difference signal. The above two difference signals are inter-field difference signals obtained between the scanning lines indicated by arrows X1 and X2 in FIG. These inter-field difference signals are each passed through a low-pass filter 3.
7.38 to the absolute value circuit 39.40.

The outputs of the absolute value circuits 39 and 40 are output from the synthesis circuit 41.
The combined output is supplied to the motion coefficient circuit 42 and becomes a control signal for the multiplier 10.17.

In the above embodiment, regarding the luminance signal, the ratio between the interfield interpolation scanning line signal and the intrafield 11n scanning line signal can be adjusted according to the movement of the subject.
Regarding the chroma signal, it is also necessary to adjust the ratio between the interfield interpolation scanning line signal and the intrafield interpolation scanning line signal in accordance with the movement of the subject. A circuit that realizes this is shown in FIG.

The same parts as in FIG. 1 will be described with the same reference numerals. That is, the condensed video signal is supplied to a luminance and chroma separation circuit 50, where it is separated into a luminance signal Y and a chroma signal C. The luminance signal Y is supplied to the input terminal 11 shown in FIG. 1 via the delay circuit 5I. A block A1 surrounded by a dashed line is the same as the circuit shown in FIG. The chroma signal C is supplied to a demodulation circuit 52 and demodulated into a ■ signal and a Q signal. and ■signal, Q
The signals are supplied to interpolation scanning line signal processing circuits A2 and A3, respectively. The interpolation scanning line signal processing circuit A2 has 53.28211 line memories 54 connected in series, and inputs and outputs of the line memories 53 are added by an adder 55 and then supplied to a coefficient unit 56. As a result, an intra-field interpolation signal is obtained from the coefficient unit 56.

The output of the coefficient unit 56 and the output of the memory 54 are combined by an adder 59 via multipliers 57 and 58, respectively, to form an interpolated scanning line signal (I). Since the multipliers 57 and 58 are controlled by the output of the motion coefficient conversion circuit 23, the ratio between the inter-field interpolation scanning line signal and the intra-field interpolation scanning line signal is adjusted according to the movement of the subject, thereby improving the image quality. Contribute to improvement. The Q signal interpolation scanning line signal processing circuit A3 has a similar configuration, and the interpolation scanning line signal processing circuit A3 has a similar configuration, and produces an interpolation scanning line signal in which the ratio between the interfield interpolation scanning line signal and the intrafield interpolation scanning line signal is well adjusted according to the movement of the subject. Signal (Q) can be obtained.

FIG. 6 shows a circuit for obtaining an interpolated scanning line signal of a chroma signal using the embodiment of FIG. In FIG. 6, the same parts as in FIGS. 4 and 5 will be described with the same reference numerals. The composite video signal is supplied to a luminance signal/chroma signal separation circuit 50, where it is separated into a luminance signal Y and a chroma signal C. The luminance signal Y is supplied to the input terminal 11 via the delay circuit 51. Block B1, which provides this terminal, is the same as the circuit shown in FIG. A signal for adjusting the ratio with the scanning line signal is derived from the motion coefficient conversion circuit 42.

On the other hand, the chroma signal is supplied to the demodulation circuit 52, and the ■ signal and Q
demodulated into a signal. Since blocks B2 and B3 have similar circuits, block B2 is shown as a representative. (2) The signal is supplied to a series circuit of a line memory 53 and a memory 54 for 26211 parts.

Then, the input and output of the line memory 53 are added by an adder 55 to produce an intra-field path scanning line signal.

The output of the memory 54 is also used as an interfield interpolation scanning line signal. The intrafield interpolation scanning line signal is supplied to a multiplier 57 via a coefficient multiplier 56, and the interfield interpolation scanning line signal is supplied to a multiplier 58. Then, the outputs of the multipliers 57 and 58 are added together by an adder 59 and derived as an interpolated scanning line signal (I). This interpolated scanning line signal (1) is also controlled by the multipliers 57 and 58 by the output from the motion coefficient conversion circuit 42, so that the inter-field interpolated scanning line signal and the intra-field interpolated scanning line signal are adjusted according to the movement of the subject. The ratio is well adjusted. Similar signal processing is performed on the Q signal side as well.

[Effects of the Invention] As explained above, the present invention always generates intra-field scanning line signals even if the circuit scale is small.
An inter-field difference signal using this intra-field scanning line signal and an inter-frame difference signal using one field memory are created, and the video information is reliably included in the inter-field difference signal. A motion detection circuit that can capture the motion of a subject can be provided.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing one embodiment of the present invention, Fig. 2 is an explanatory diagram shown to explain the operation of the circuit shown in Fig. 1, and Fig. 3 is a diagram showing another embodiment of the invention. Explanatory diagram for, 4th
The figure is a circuit diagram that obtains the operation shown in Figure 3, Figures 5 and 6 are circuit diagrams showing other embodiments of the present invention, Figure 7 is an explanatory diagram of scanning line interpolation, and Figure 8 is a conventional circuit diagram. FIG. 3 is a diagram for explaining a problem with scanning line interpolation processing. 12.13...Memory, 14.18. ...adder,
15... Coefficient unit, 16.17... Multiplier, 20...
- Subtractor, 21...Low pass filter, 22...Absolute value circuit, 23...Motion coefficient conversion circuit.

Claims (1)

[Claims] In a circuit for detecting motion information of a subject image reproduced by an interlace-scanned television signal, a memory having a capacity for one field of the television signal and two scanning line signals in the memory are used to detect the scanning line. means for obtaining an interpolation signal; a subtraction circuit that calculates an inter-field difference signal using the scanning line interpolation signal and the output signal of the memory; and a subtraction circuit that calculates an inter-field difference signal by passing the inter-field difference signal through a coefficient circuit to obtain a temporal movement coefficient of the subject signal. 1. A motion detection circuit comprising: means for calculating .