JPH04326276A - Motion detecting circuit and motion adaptive scan line interpolating circuit - Google Patents

Abstract

PURPOSE:To present the motion detecting circuit, which can prepare high- accuracy motion signals by operating the motion adaptive scan line interpolating circuit to improve the degradation of resolution especially for the vertical edge part of slow motion, concerning the motion detecting circuit for television signals. CONSTITUTION:The motion detecting circuit is composed of an inter-field motion detecting means 1, inter-frame motion detecting means 2, edge detecting means 3 and mixing circuit 4 so that the signal of the vertical edge part in the image of slow motion can be judged as a still picture. Thus, since inter-field interpolation can be executed to the vertical edge part in the image of slow motion, the degradation of the vertical resolution frequently recognized in the image of slow motion can be prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing circuit for television signals, and more specifically to a motion detection circuit and motion detection circuit that output a motion signal used as a control signal for a motion adaptive signal processing circuit. The present invention relates to an adaptive scan line interpolation circuit.

0002

2. Description of the Related Art In recent years, the size and performance of displays in current color television signal receiving apparatuses have increased. Along with this, deterioration in image quality due to the signal format of television signals has become noticeable. In response, various techniques for improving image quality using digital signal processing techniques and large-capacity digital memories have been proposed. One example is motion adaptive signal processing. This motion adaptive signal processing detects the motion of an image using a motion detection circuit, and switches the processing of the television signal according to the motion.

Conventional examples of this motion detection circuit and motion adaptive signal processing circuit are described in Chapter 6 of "Clear Vision Handbook" edited by Clear Vision Promotion Council.
"Pages 129 to 155". This conventional example will be described below with reference to the drawings.

First, a conventional example of a motion detection circuit will be explained with reference to FIG. FIG. 2 is a block diagram of a conventional motion detection circuit. In FIG. 2, 20 is a frame memory, 21 is a subtraction circuit, 22 is a low-pass filter (hereinafter referred to as LPF), 23 is an absolute value circuit, 24 is an input terminal, and 25 is an output terminal.

[0005] Here, the television signal input to the input terminal 24 is an NTSC composite color television signal (hereinafter referred to as a color television signal).
is given as an example. The color television signal inputted from the input terminal 24 is first inputted to the frame memory 20, and a color television signal delayed by one frame period is obtained from the frame memory 20. The color television signal delayed by one frame period and the color television signal from the input terminal 24 are input to the subtraction circuit 21, and the subtraction circuit 21 outputs a one-frame difference signal. Here, if the one-frame difference signal is zero, it is determined to be a still image, and if it is not zero, it is determined to be a moving image, so that movement of the image can be detected.

[0006] However, in a color television signal, the luminance signal components are in the same phase and the color signal components are in opposite phases during one frame, so the above-mentioned frame-to-frame difference signal includes color signal components in addition to the motion component. It is included. Therefore, the color signal component is removed from the one-frame difference signal by limiting the band of the color signal using the LPF 22. Thereafter, the positive and negative polarities of the difference signal are removed by the absolute value circuit 23, and the signal is output from the output terminal 25 as a motion signal. This motion signal is then used as a control signal for the motion adaptive signal processing circuit.

Next, a motion adaptive scanning line interpolation circuit (hereinafter referred to as a motion adaptive interpolation circuit) will be described as an example of a motion adaptive signal processing circuit.

This motion adaptive interpolation circuit is a signal processing circuit that converts an interlaced scanning television signal (hereinafter referred to as an interlaced television signal) into a progressive scanning television signal (hereinafter referred to as a non-interlaced television signal). When creating an interpolated scanning line signal, it performs signal processing according to the movement of the image and outputs a non-interlaced television signal that can display high-quality images without line flickers. Hereinafter, the circuit operation of this motion adaptive interpolation circuit will be explained using FIG. 3.

FIG. 3 is a block diagram of a motion adaptive interpolation circuit. In FIG. 3, 26 is a line memory, 27 is a field memory, 28 is an addition circuit, 29 is a constant multiplication circuit, 3
0 is a mixing circuit, 31 is a double speed conversion circuit, 32 and 33 are input terminals, and 34 is an output terminal. Here, the number of scanning lines is 5 as the television signal input to the input terminal 32.
NTS, which is a 25-line interlaced television signal.
C-system television signal (hereinafter referred to as television signal)
This will be explained using an example. Further, from the input terminal 33, a motion signal generated by the motion detection circuit shown in FIG. 2 is input.

[0010] First, a television signal input from the input terminal 32 is input to the line memory 26 . line memory 2
6 is 1H (1H is one horizontal scanning period of the television signal)
Outputs delayed TV signals. This 1H delayed TV signal and the TV signal from the input terminal 32 are added to the adder circuit 2.
8 and multiplied by 1/2 by a constant multiplier circuit 29. As a result, a signal obtained by averaging the 1H delayed television signal and the television signal from the input terminal 32 is obtained from the constant multiplier circuit 29. This averaged signal is then input to the mixing circuit 30 as a moving image interpolation signal.

On the other hand, 1 output from the line memory 26
The television signal delayed by H is branched and input to the field memory 27. The field memory 27 performs processing to delay the input signal by 262H. Therefore, the signal output from the field memory 27 is transmitted to the input terminal 32.
The signal is delayed by 263H with respect to the TV signal from . This 263H delayed television signal is then input to the mixing circuit 30 as a still image interpolation signal. Mixing circuit 3
0 mixes and outputs a still image interpolation signal and a moving image interpolation signal such that the mixing ratio changes depending on the degree of movement of the motion signal from the input terminal 33.

Here, when the movement of the motion signal is small, the mixing circuit 30 mainly selects and outputs the interpolation signal for still images, and when the movement of the motion signal is large, it mainly selects and outputs the interpolation signal for moving images. It operates to output the following data. Then, the double speed conversion circuit 31 inputs the television signal from the input terminal 32 as a real signal and the output signal of the mixing circuit 30 as an interpolation signal, and
After time compression, the real signal/interpolated signal is switched line by line and outputted to the output terminal 34 as a non-interlaced television signal.

Next, the operation of the above motion adaptive interpolation circuit will be explained using FIG. 4. FIG. 4 is a scanning line structure diagram showing the operating principle of motion adaptive interpolation. In Figure 4,
The horizontal direction means time (field), and the vertical direction means the vertical direction of the screen. Now, assume that the current television signal of interest is A0 in the m-th field. In this case, the mixing circuit 30 of FIG.
An interpolated signal for the I0 portion of the m-th field shown in FIG. 4 is created. At this time, the 1H delayed television signal obtained from the line memory 26 in FIG. 3 becomes A1. Also, since the television signal is an interlaced signal with 525 scanning lines,
The 263H delayed television signal obtained from the field memory 27 becomes A263 of the (m-1)th field. Here, A263 is a still image interpolation signal, and a signal obtained by averaging A1 and A0 is a moving image interpolation signal. Then, the mixing circuit 30 in FIG. 3 mixes both interpolation signals according to the movement of A0, and outputs the mixture as an interpolation signal I0. Thereafter, double speed conversion processing is performed in the double speed conversion circuit 31, and a non-interlaced television signal is output from the output terminal 34.

[0014] With this operation, in the still picture part, the signal of one field before, which has a high signal correlation, is used as an interpolation signal (hereinafter referred to as interfield interpolation). It is possible to improve image quality deterioration such as line flicker and vertical resolution deterioration that occurs in parts, that is, black and white transition parts in the vertical direction of the image. On the other hand, when interpolating between fields for video parts, the correlation between the signals is small, resulting in double images and blurring, so interpolation signals are created using signals within the same field (hereinafter referred to as , called intrafield interpolation).

As described above, in the above conventional example, the motion detection circuit and the motion adaptive interpolation circuit prevent image quality deterioration such as line flicker and vertical resolution deterioration that occurs in current television receivers, and achieve high image quality. ing.

[0016]

The motion adaptive interpolation circuit of the above-mentioned conventional example performs intra-field interpolation for the moving image portion. For this reason, it is not possible to improve the resolution deterioration of the vertical edge portion, which is possible with interpolation processing of the still image portion. However, since the human eye's sensitivity to moving objects is lower than its sensitivity to static objects, this is not a major problem. However, in the case of slow-moving images, there is a problem in that this deterioration in vertical resolution is easily recognized. The processing of the motion adaptive interpolation circuit for slow-moving vertical edge portions will be described below with reference to FIG.

FIG. 5 is a scanning line structure diagram showing a motion detection and interpolation operation of a vertical edge portion of a moving image by a conventional motion detection circuit. In FIG. 5, the horizontal axis indicates the time (field) direction, and the vertical axis indicates the vertical direction of the screen. The image shown in Figure 5 is
It shows how a black-level object moves from the bottom of the screen to the top in two fields for one line in a white-level background.The black circle is a black-level signal representing the object, and the white circle is a white-level signal representing the background. be. Now, assume that the current field of interest is the m-th field.

First, motion is detected by the motion detection circuit described in FIG. The motion detection circuit shown in FIG. 2 determines the motion of the current signal by subtracting the current signal and the signal one frame before. That is, the movement of the signal a0 in the m-th field in FIG. 5 is created from the difference between a0 and the signal one frame before a0, that is, a2 in the (m-2)th field. Thereafter, each movement is detected from the difference between b0 and b2, c0 and c2, d0 and d2, e0 and e2, and f0 and f2 in the same manner. The results are that there is no signal level difference between frames, a0, c0, d0, and f0 are determined to be still images, there is a signal level difference between frames, b
0 and e0 are determined to be moving images.

Next, an interpolation signal is created in the motion adaptive interpolation circuit described in FIGS. 3 and 4. Let us now assume that the current signal of interest is a0. In this case, the part to be interpolated is ai
becomes. Here, the motion signal a0 is a signal determined to be a still image. Therefore, a1 (white level) one field before, ie, the (m-1)th field, is interpolated to ai. Similarly, ci has c1 (black level), d
d1 (black level) is interpolated for i, and f1 (white level) is interpolated for fi.

Next, let b0 be the current signal of interest. In this case, the part to be interpolated is bi. Here, the motion signal b0 is a signal determined to be a moving image. Therefore, b
The average signal (gray level) of b0 and a0 is interpolated to i. Similarly, the average signal (gray level) of e0 and d0 is interpolated to ei.

In the above interpolation process, since gray level signals are interpolated to the bi and ei portions, it is not possible to improve the resolution of the vertical edge portions. In other words, if the motion adaptive interpolation circuit is controlled by the motion signal created by the conventional motion detection circuit, the degradation in resolution cannot be improved for slow-moving images, so this degradation in vertical resolution will be noticeable. There was a problem.

An object of the present invention is to provide a motion detection circuit that can generate a highly accurate motion signal in order to operate a motion adaptive interpolation circuit so as to improve the resolution deterioration of slow-moving vertical edge portions as described above. It's about doing.

[0023]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides inter-field motion detection means for inputting a television signal and detecting the motion of an image therein using inter-field signals. and an interframe motion detection means for detecting the motion of an image in the television signal using an interframe signal, an output signal of the interframe motion detection means and an output signal of the interfield motion detection means. The present invention is characterized in that the motion detection circuit is constituted by a mixing circuit that mixes and outputs the mixture and a control signal generating means that generates a control signal for controlling the mixing process in the mixing circuit from the television signal.

[0024]

[Operation] The inter-field motion detection means inputs a television signal and detects the motion of an image therein by utilizing the correlation of the signals between fields. The interframe motion detection means detects motion of an image in a television signal by using correlation of signals between frames. The control signal generating means generates a control signal (for example, a vertical edge signal of an image) from the television signal in order to control the mixing process in the mixing circuit. The mixing circuit responds to the control signal (for example, the vertical edge signal of the image) created by the control signal creation means.
The motion signal detected by the inter-field motion detection means and the motion signal detected by the inter-frame motion detection means are mixed and output.

As a result, the signal of the slow-moving vertical edge portion is determined to be a still image, and inter-field interpolation can be performed in the motion adaptive interpolation circuit. Therefore, it is possible to prevent deterioration of the vertical resolution of slow-moving vertical edge portions.

[0026]

[Embodiment] An embodiment of the present invention will be explained below with reference to FIG. FIG. 1 is a block diagram showing a first embodiment of the present invention.

In FIG. 1, 1 is an inter-field motion detection means, 2 is an inter-frame motion detection means, 3 is an edge detection means, 4 is a mixing circuit, 5 is an input terminal, 6 is an output terminal, 7 is a field memory, and 8 is a mixing circuit. , 17 is a line memory, 14 is a frame memory, 9, 10, 15, 18 are subtraction circuits, 11
, 12, 16, and 19a are absolute value circuits, and 13 is a selection circuit. Further, 19b is a conversion circuit that converts, for example, 8-bit data into 1-bit data.

The present invention is characterized in that in image motion detection, motion detection is performed not only between frames but also between fields, and both motion signals are combined to generate a motion signal.

The television signal input to the input terminal 5 will be explained using an example of a television signal having 525 scanning lines, interlaced scanning, and consisting of 8-bit data. Further, a case will be explained using an example in which the selection circuit 13 is a minimum value selection circuit that selects and outputs the one with a smaller signal level among two input signals. The television signal inputted from the input terminal 5 is first inputted to the interfield motion detection means 1, and the motion of the image is detected from the correlation of the signals between fields.

The inter-field motion detecting means 1 first inputs the television signal to the field memory 7 and the line memory 8, and outputs the television signal delayed by 263H from the field memory 7 and the television signal delayed by 1H from the line memory 8. Output each. Then, in the subtraction circuit 9, the TV signal from the input terminal 5 and the 2
The 63H delayed television signal is subtracted to obtain a first inter-field difference signal. Further, in the subtraction circuit 10, the 263H delayed television signal from the field memory 7 and the 1H delayed television signal from the line memory 8 are subtracted to obtain a second interfield difference signal.

Thereafter, the first inter-field difference signal is input to the absolute value circuit 11, and the second inter-field difference signal is input to the absolute value circuit 12. In the absolute value circuits 11 and 12, the positive and negative polarities of the difference signals are removed, and the absolute value circuit 1
1 is output as a first inter-field motion signal, and the output signal of the absolute value circuit 12 is output as a second inter-field motion signal. The first inter-field motion signal and the second inter-field motion signal are input to the selection circuit 13, and the one with the smaller signal level is selected and output as the inter-field motion signal.

On the other hand, the television signal from the input terminal 5 is branched and input to the interframe motion detection means 2, where the motion of the image is detected from the correlation of the signals between frames. The interframe motion detection means 2 delays the television signal from the input terminal 5 by one frame period (525H) in the frame memory 14 and outputs the delayed signal. Thereafter, in the subtraction circuit 15, the television signal from the input terminal 5 and the 52
The 5H delayed television signal is subtracted to obtain an interframe difference signal. Then, in the absolute value circuit 16, the positive and negative polarities of the difference signal are removed and output as an inter-frame difference signal.

The television signal from the input terminal 5 is further branched and input to the edge detection means 3. The edge detection means 3 generates an edge signal that becomes a control signal for a mixing circuit 4, which will be described later. The edge detection means 3 delays the television signal from the input terminal 5 by 1H in the line memory 17 and outputs the delayed signal. Thereafter, the subtraction circuit 18 subtracts the television signal from the input terminal 5 and the 1H delayed television signal from the line memory 17 to obtain a 1H difference signal. Here, if an edge portion exists in the vertical direction within the same field, a significant signal component occurs in the 1H difference signal in that portion. Also, if it is not an edge part,
The 1H difference signal becomes zero. Therefore, by creating a 1H difference signal, the vertical edge portion of the image can be detected. Thereafter, the 1H difference signal is input to the absolute value circuit 19a, the positive and negative polarities of the difference signal are removed, and the conversion circuit 1
9b, it is output as a 1-bit edge signal.

Next, the inter-field motion signal detected by the inter-field motion detection means 1 and the inter-frame motion signal detected by the inter-frame motion detection means 2 are input to the mixing circuit 4. In the mixing circuit 4, both signals are mixed according to the edge signal detected by the edge detection means 3. Here, if the edge signal is binary (with/without edge), the mixing circuit 4 selects and outputs the inter-field motion signal if there is an edge, and selects the inter-frame motion signal if there is no edge. and output it.

Further, when the edge signal has three or more levels, the mixing circuit 4 mixes and outputs the inter-field motion signal and the inter-frame motion signal so that the mixing ratio changes depending on the level of the edge signal. . That is, when the level of the edge signal is high, the inter-field motion signal is mainly selected and output, and when the level of the edge signal is low, the inter-frame motion signal is mainly selected and output. This allows smooth switching between the inter-field motion signal and the inter-frame motion signal. The output signal of the mixing circuit 4 is then output as a motion signal that controls the motion adaptive interpolation circuit. In this case, a circuit that converts 8-bit data into 2-bit, 3-bit, . . . is used as the conversion circuit 19b. In addition, when using 8-bit data as an edge signal, the conversion circuit 1
9b is unnecessary.

Next, the motion detection operation of the motion detection circuit will be explained with reference to FIGS. 6 and 7. first,
The operation of the inter-field motion detection means 1 will be explained using FIG. 6. FIG. 6 is a scanning line structure diagram showing the operation of the inter-field motion detection means 1. The horizontal direction in FIG. 6 means time (field), and the vertical direction means the vertical direction of the screen. Now, assume that the current television signal of interest is the m-th field, A0. At this time, the 1H delayed television signal obtained from the line memory 8 in FIG. 1 becomes A1. Further, since the television signal is an interlaced signal with 525 scanning lines, the television signal delayed by 263H obtained from the field memory 7 becomes A263 of the (m-1)th field. Here, the subtraction circuit 9 and absolute value circuit 11 in FIG. 1 take the absolute value of the difference between A0 and A263, and create a first interfield motion signal. Further, the subtraction circuit 10 and absolute value circuit 12 in FIG. 1 take the absolute value of the difference between A1 and A263, and create a second interfield motion signal. Then, in the selection circuit 13 of FIG. 1, the smaller one of the first interfield motion signal and the second interfield motion signal is selected and outputted as the interfield motion signal for A0.

Next, the operation of the interframe motion detection means 2 will be explained using FIG. 7. FIG. 7 is a scanning line structure diagram showing the operation of the interframe motion detection means 2. Similar to FIG. 6, the horizontal direction in FIG. 7 means time (field), and the vertical direction means the vertical direction of the screen. The current TV signal that is attracting attention now is m
Let the field number be A0. At this time, the 525H delayed television signal obtained from the frame memory 14 in FIG. 1 becomes A525 of the (m-2)th field. Here, A0
The absolute value of the difference between A525 and A525 is taken and becomes the interframe motion signal for A0. Then, in the mixing circuit 4 of FIG. 1, the inter-field motion signal and this inter-frame motion signal are mixed according to the level of the edge signal detected by the edge detection means 3 of FIG. 1, and output as a motion signal for A0. be done.

Next, the processing of the motion adaptive interpolation circuit for slow-moving vertical edges based on the motion signal detected by the motion detection circuit of the present invention will be explained with reference to FIG. Figure 8 shows
FIG. 3 is a scanning line structure diagram showing the motion detection and interpolation operation of a vertical edge portion of a moving image by the motion detection circuit of the present invention. In FIG. 8, the horizontal axis indicates the time (field) direction, and the vertical axis indicates the vertical direction of the screen. Similar to FIG. 5, the image shown in FIG. 8 shows a black-level object moving from the bottom of the screen to the top in two fields for one line in a white-level background, and the black circles represent the black-level signals representing the objects. The white circle is a white level signal representing the background. Now, assume that the current field of interest is the m-th field.

First, edge detection by the edge detection means 3 in FIG. 1 will be described. Here, a case will be described in which the edge signal output from the edge detection means is binary (with/without edge). The edge detection means 3 determines the presence or absence of an edge from the difference between the current signal and the signal delayed by 1H. Therefore, a0, b0, c of the mth field
Among the signals of 0, d0, e0, and f0, the ones that are determined to have edges are b0 and e, which have a level difference from the signal 1H ago.
0, and the signals a0, c0, d0, and f0, which have no level difference from the signal 1H before, are determined to have no edge.

The mixing circuit 4 in FIG. 1 selects the inter-field motion signal when there is an edge, and selects the inter-frame motion signal when there is no edge, so in this case, the inter-field motion signal is selected. The motion signals are b0 and e0, and the interframe motion signals are a0, c0, d0, and f0.

Now, a0 to select the interframe motion signal
If we pay attention to , the movement of a0 is 525H before a0 and a0,
That is, it is created from the difference between the (m-2)th field and a2. As a result, since both a0 and a2 are white level signals, it is determined that the image is a still image. Similarly, c0,
The movements of d0 and f0 are created from the differences between c0 and c2, d0 and d2, and f0 and f2, respectively, and are determined to be still images.

On the other hand, selecting the inter-field motion signal b
Focus on 0. The inter-field motion detection means 1 in FIG.
A first inter-field motion signal is created from the difference between b0 and a signal 263H before b0, that is, b1 of the (m-1)th field. Further, a second inter-field motion signal is created from the difference between b1 and b0 1H earlier signal, that is, a0. Then, of the two inter-field motion signals, the one with the smaller signal level is set as the b0 motion signal. As a result, the second inter-field motion signal created from b1 and a0, both of which have a white level, is selected, and the motion of b0 is determined to be a still image. Similarly, if we pay attention to e0, which detects movement between fields, e1 and d, both of which are at the black level,
A second inter-field motion signal created from 0 is selected, and the motion of e0 is determined to be a still image. By the above processing, m-th field a0, b0, c0, d0, e0
All motion signals for and f0 are determined to be still images.

Therefore, in the motion adaptive interpolation circuit,
The method for creating interpolated signals for the ai, bi, ci, di, ei, and fi portions of the m-th field is all interfield interpolation. That is, a1 for ai, b1 for bi,
c1 is interpolated to ci, d1 is interpolated to di, e1 is interpolated to ei, and f1 is interpolated to fi. As a result, the m-th field non-interlaced television signal output from the motion adaptive interpolation circuit becomes a signal with a higher vertical resolution than the conventional example described with reference to FIG.

As described above, according to this embodiment, in image motion detection, in addition to motion detection between frames, motion detection is also performed between fields, and both motion signals are synthesized to form a motion signal. The signal at the vertical edge portion can be determined to be a still image. As a result, the motion adaptive interpolation circuit can perform interfield interpolation on the above portion, which has the effect of preventing deterioration in vertical resolution that is likely to be recognized in slow-moving images.

Next, an embodiment of a motion adaptive interpolation circuit using the motion detection circuit of the present invention will be described with reference to FIG. Figure 9
1 is a block diagram showing an embodiment of a motion adaptive interpolation circuit using the motion detection circuit of the present invention. FIG. In FIG. 9, 35
is a motion adaptive interpolation circuit, 36 is a line memory, 37, 38
is field memory, and other parts indicated by symbols are shown in Figure 1.
and the same parts as those indicated by the same reference numerals in FIG.

This embodiment describes a motion detection circuit and a motion detection circuit configured to share each memory used for delaying a television signal in a motion adaptive interpolation circuit, an inter-field motion detection means, an inter-frame motion detection means, and an edge detection means. This is an example of an adaptive interpolation circuit. In this embodiment, as in the previous embodiment, an interlaced scanning television signal with 525 scanning lines will be explained as an example of the television signal input to the input terminal 5.

The television signal input from the input terminal 5 is first input to the line memory 36. line memory 36
Then, a TV signal delayed by 1H is output. This 1H delayed television signal is then input to the field memory 37. The field memory 37 stores input signals at 262
Performs H delay processing. Therefore, the signal output from the field memory 37 is delayed by 263H with respect to the television signal from the input terminal 5. This 263H delayed television signal is further input to the field memory 38. The field memory 38 outputs a signal delayed by 525H with respect to the television signal from the input terminal 5. As described above, by cascading one line memory and two field memories, a television signal delayed by 1H, a television signal delayed by 263H, and a television signal delayed by 525H are obtained.

[0048] Then, the inter-field motion detection means 1
A current television signal, a television signal delayed by 1H, and a television signal delayed by 263H are input from the input terminal 5. In the inter-field motion detecting means 1, an inter-field motion signal is detected in the same manner as in the previous embodiment by processing in subtraction circuits 9, 10, absolute value circuits 11, 12, and selection circuit 13. On the other hand, the interframe motion detection means 2 receives the current television signal and the television signal delayed by 525H. In the interframe motion detection means 2, an interframe motion signal is detected by a subtraction circuit 15 and an absolute value circuit 16, as in the previous embodiment.

Furthermore, the edge detection means 3 receives the current television signal and the television signal delayed by 1H, and the subtraction circuit 18
And the edge signal is detected by the absolute value circuit 19a as in the previous embodiment. Thereafter, when the 1-bit signal with or without an edge outputted from the conversion circuit 19b is applied to the mixing circuit 4, the inter-field motion signal detected by the inter-field motion detection means 1 and the inter-frame The interframe motion signal detected by the motion detection means 2 is input, and both signals are mixed according to the edge signal detected by the edge detection means 3. The output signal of the mixing circuit 4 is then output as a motion signal that controls the motion adaptive interpolation circuit 35.

The motion adaptive interpolation circuit 35 receives the current television signal, the television signal delayed by 1H, the television signal delayed by 263H, and the motion signal from the mixing circuit 4. Similar to the process explained in FIG. 3, the motion adaptive interpolation circuit 35 uses a signal obtained by averaging the current television signal and a television signal delayed by 1H as a video interpolation signal, and a television signal delayed by 263H as a still image interpolation signal. The signals are input to the mixing circuit 30 and mixed according to the motion signal from the mixing circuit 4. Then, the output signal from the mixing circuit 30 is used as an interpolation signal, and the current television signal is used as a real signal, which are input to a double speed conversion circuit 31, and a non-interlaced television signal is output from an output terminal.

As described above, according to this embodiment, in image motion detection, in addition to inter-frame motion detection, motion detection is performed between fields as in the previous embodiment, and both motion signals are combined to form a motion signal. Therefore, it is possible to determine that a slow-moving vertical edge portion is a still image. This results in
Since the motion adaptive interpolation circuit can perform interfield interpolation on the above portion, it is possible to prevent deterioration in vertical resolution that is easily recognized in slow-moving images. Another advantage is that the circuit configuration can be realized on a smaller scale by sharing each memory used for delaying the television signal in the motion adaptive interpolation circuit, the interfield motion detection means, the interframe motion detection means, and the edge detection means. There is.

Next, a second embodiment of the present invention, which is an improvement on the mixing circuit 4 of the first embodiment, will be described with reference to FIG. FIG. 10 is a block diagram showing the configuration of the mixing circuit 4 of the second embodiment. In FIG. 10, 39 is a selection circuit;
is a minimum value selection circuit, 41, 42, 43 are input terminals, and 6 is an output terminal.

This embodiment is characterized in that in the mixing process of the inter-field motion signal and the inter-frame motion signal, when there is an edge, the one with the smaller signal level of both motion signals is output as the motion signal. . Also here, the case where the edge signal is binary (with edge/without edge) will be explained as an example.

The input terminal 41 receives an inter-field motion signal,
An interframe motion signal is input to the input terminal 42, and an edge signal is input to the input terminal 43. Then, in the selection circuit 39, either the inter-field motion signal or the inter-frame motion signal is selected depending on the edge signal (with an edge...the inter-field motion signal is selected; without an edge...the inter-frame motion signal is selected). choice). Then, the output signal from the selection circuit 39 and the interframe motion signal from the input terminal 42 are inputted to the minimum value selection circuit 40.
Of both signals, the one with the smaller signal level is selected and outputted from the output terminal 6 as a motion signal.

As a result, when there is an edge, the minimum value selection circuit 40 selects the one with the smaller signal level of the inter-field motion signal and the inter-frame motion signal as the motion signal. On the other hand, in the case of no edge, two equal interframe motion signals are input to the minimum value selection circuit 40, so that the minimum value selection circuit 40 ultimately outputs the interframe motion signal as a motion signal.

Next, the effects of the second embodiment will be explained in comparison with the first embodiment. FIG. 12 is a scanning line structure diagram showing motion detection and interpolation operations by the motion detection circuit (see FIG. 1) of the first embodiment, and FIG. FIG. 2 is a scan line structure diagram illustrating motion detection and interpolation operations by the circuit. In FIGS. 12 and 13, the horizontal axis indicates the time (field) direction, and the vertical axis indicates the vertical direction of the screen. The images shown in FIGS. 12 and 13 are horizontal stripes with the highest vertical frequency that can be expressed when a television signal with 525 scanning lines is a non-interlaced signal. In other words, the image changes from white to black for each raster, and the image is static. , black circles are black level signals and white circles are white level signals. Furthermore, it is assumed that the signal at a0 of the m-th field is a gray level noise signal, and is shaded with diagonal lines.

Here, attention is paid to the b0 (white level) signal of the m-th field. Since the signal (a0) 1H before b0 is a noise signal (gray level), b0 has an edge.

First, the operation of the motion detection circuit of the first embodiment will be explained using FIG. 12. In the first embodiment, an inter-field motion signal is used when there is an edge. The inter-field motion detection means 1 of FIG. 1 creates a first inter-field motion signal from the difference between b0 and a signal 263H before b0, that is, b1 of the (m-1)th field. Furthermore, a second inter-field motion signal is created from the difference between b1 and a0. Then, of the two inter-field motion signals, the one with the smaller signal level is set as the b0 motion signal. In this case, since the first inter-field motion signal is the difference between the black level b1 and the white level b0, it produces a significant signal component and becomes a signal that is determined to be a moving image. Also,
Since the second inter-field motion signal is also the difference between the black level b1 and the gray level a0, it becomes a signal that is determined to be a moving image. As a result, the motion signal b0 output from the selection circuit 13 in FIG. 1 is determined to be a moving image. therefore,
In the motion adaptive interpolation circuit, the interpolation signal of bi is b0 and a
It becomes a signal with a gray level slightly higher than a0, which is an average of 0.

This phenomenon is caused by the presence of a noise signal a0, so that intra-field interpolation is performed even though b0 is an edge portion of a still image, resulting in a deterioration of vertical resolution.

Next, the operation of the motion detection circuit of the second embodiment using the mixing circuit 4 of FIG. 10 will be explained using FIG. 13. In the second embodiment, when there is an edge, the motion signal is the one with the smaller signal level of the inter-field motion signal and the inter-frame motion signal. That is, in this case, among the inter-frame motion signals obtained from the difference between the inter-field motion signal explained in FIG. 12 and b2, which is a signal one frame before b0, the one with the smaller signal level is b0.
This is a motion signal for Here, since b0 and b2 are signals of the same white level, the interframe motion signal is a signal that is determined to be a still image. Therefore, the inter-field motion signal that is determined to be a moving image is not selected, and b0
The motion signal for this will be a still image. As a result, in the motion adaptive interpolation circuit, the interpolation signal of bi becomes b1 by interfield interpolation. This makes it possible to prevent vertical resolution from deteriorating due to noise.

Although the mixing circuit 4 of this embodiment has been described using FIG. 10 as an example, the present invention is not limited to this configuration. The mixing circuit 4 of this embodiment may be configured to select and output the one with the smaller signal level between the inter-field motion signal and the inter-frame motion signal when there is an edge. For example, the configuration shown in FIG. 11 is easily conceivable. The mixing circuit 4 shown in FIG. 11 has a configuration in which a minimum value selection circuit 44 is placed at the front stage and a selection circuit 45 is placed at the rear stage. In this case as well, a motion signal that is exactly the same as the motion signal obtained in FIG. 10 is obtained from the output terminal 6.

As described above, according to the second embodiment, in motion detection of an image, motion detection is performed not only between frames but also between fields, and both motion signals are combined to detect motion. Since it is a signal, it is possible to determine that a slow-moving vertical edge portion is a still image. This allows the motion adaptive interpolation circuit to perform inter-field interpolation on the above portion, thereby preventing deterioration in vertical resolution that is likely to be recognized in slow-moving images.

Further, in the case where there is an edge, the inter-field motion signal and the inter-frame motion signal, whichever has a smaller signal level, is output as the motion signal. This has the effect of preventing deterioration in vertical resolution caused by performing intra-field interpolation on still images due to noise and the like.

In the first and second embodiments described above, the selection circuit 13 in the inter-field motion detection means 1 has the following configuration:
Although the minimum value selection circuit has been described as an example, the present invention is not limited to this. Depending on the special image, by configuring the selection circuit 13 with a minimum value selection circuit, a fast-moving vertical edge portion may be determined to be a still image, and image quality deterioration such as double images may occur. In this case, if the selection circuit 13 is configured with an average value calculation circuit or the like, the above-described image quality deterioration can be alleviated, and the resolution of slow-moving vertical edge portions can be sufficiently improved.

Furthermore, in each of the above embodiments, the explanation was given using an example of an edge signal in which a control signal for controlling the operation of the mixing circuit 4 is created from a 1H difference signal, but this is not limited to this configuration either. do not have. Basically, any configuration may be used as long as the mixing process of the inter-field motion signal and the inter-frame motion signal in the mixing circuit 4 can be controlled using some information in the image. For example, even if a horizontal edge signal is detected in addition to a vertical edge signal and a control signal generated from both edge signals is used, the effects of the invention will not change.

Furthermore, in each of the above embodiments, an NTSC television signal, which is an interlaced signal with 525 scanning lines, was used as an example of the television signal input from the input terminal 5. However, the present invention is not limited to this. The input signal of the present invention may be any television signal that performs interlaced scanning. For example, it is possible to handle the case where an interlaced scanning television signal with 625 scanning lines, such as the PAL system, is input. In this case, the present invention can be applied by changing the delay period of the field memory and frame memory.

Further, in each of the above embodiments, only the scanning method for the television signal inputted from the input terminal 5 has been mentioned, but the present invention is not limited to this, and the present invention can be applied to, for example, the NTSC method. It is also possible to input television signals including color signal components such as composite color television signals. In this case, it goes without saying that the present invention can be applied by removing color signal components present in the high frequency range of the television signal using an LPF or the like.

[0068]

According to the present invention, in image motion detection, motion detection is performed not only between frames but also between fields, and both motion signals are combined to form a motion signal. It is possible to determine that the signal at the edge portion is a still image. As a result, if the motion detection circuit of the present invention is applied to a motion adaptive interpolation circuit, interfield interpolation can be performed for the above portion, thereby preventing deterioration of vertical resolution that is likely to be recognized in slow-moving images. It has the effect of being able to

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional motion detection circuit.

FIG. 3 is a block diagram showing a motion adaptive interpolation circuit.

FIG. 4 is a scan line structure diagram showing the operating principle of motion adaptive interpolation.

FIG. 5 is a scanning line structure diagram showing a motion detection and interpolation operation of a vertical edge portion of a moving image by a conventional motion detection circuit.

FIG. 6 is a scanning line structure diagram showing the operation of inter-field motion detection.

FIG. 7 is a scanning line structure diagram showing the operation of interframe motion detection.

FIG. 8 is a scanning line structure diagram illustrating motion detection and interpolation of a vertical edge portion of a moving image by the motion detection circuit of the present invention.

FIG. 9 is a block diagram showing one embodiment of a motion adaptive interpolation circuit using the present invention.

FIG. 10 is a block diagram showing one embodiment of the mixing circuit 4. FIG.

FIG. 11 is a block diagram showing one embodiment of the mixing circuit 4. FIG.

FIG. 12 is a scan line structure diagram showing motion detection and interpolation operations.

FIG. 13 is a scan line structure diagram showing motion detection and interpolation operations.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Inter-field motion detection means, 2... Inter-frame motion detection means, 3... Edge detection means, 4... Mixing circuit.

Claims (6)

[Claims] 1. An inter-field motion detection means (1) for inputting a television signal and detecting the motion of an image therein using an inter-field difference signal; An inter-frame motion detection means (2) detects using an inter-frame difference signal, and outputs a mixture of the output signal of the inter-frame motion detection means (2) and the output signal of the inter-field motion detection means (1). Mixed circuit (4)
and a control signal generating means for generating a control signal for controlling the mixing process in the mixing circuit (4) from the television signal by detecting a vertical edge portion of an image. circuit. 2. The motion detection circuit according to claim 1, wherein the inter-field motion detection means (1) includes a line memory (8) for delaying and outputting the television signal, and a line memory (8) for delaying and outputting the television signal. a field memory (7) that outputs a signal from the field memory (7), and a first subtraction circuit that subtracts the output signal of the field memory (7) from the television signal
9), a second subtraction circuit (10) for subtracting the output signal of the field memory (7) and the output signal of the line memory (8), and the output signal of the first subtraction circuit (9). a first absolute value circuit (11) that takes the absolute value of the output signal of the second subtraction circuit (10); a second absolute value circuit (12) that takes the absolute value of the output signal of the second subtraction circuit (10); It is characterized by comprising a selection circuit (13) which inputs the output signal of the circuit (12) and the output signal of the first absolute value circuit (11) and selects and outputs one of them. Motion detection circuit. 3. The motion detection circuit according to claim 2, wherein the selection circuit (13) comprises a motion detection circuit (13) that is connected to the first absolute value circuit (11).
and the output signal of the second absolute value circuit (12) as inputs, and selects and outputs the one having a smaller signal level. 4. The motion detection circuit according to claim 1, wherein said mixing circuit (4) comprises said inter-field motion detection means (
The output signal of 1), the output signal of the interframe motion detection means (2), and the output signal of the control signal generation means are input, and when the output signal of the control signal generation means has a significant signal component, is the inter-field motion detection means (1
) and the output signal of the interframe motion detection means (2), whichever has a smaller signal level is selected and output. 5. For an interlaced television signal that is an input signal, signal processing between fields and signal processing within the same field is performed in accordance with the movement of an image in the interlaced television signal. A motion adaptive scanning line interpolation circuit for creating a double speed converted progressive scanning television signal, characterized in that the motion detection circuit according to any one of claims 1 to 4 is applied thereto. interpolation circuit. 6. A line memory (36) which receives a television signal as an input, a first field memory (37) which receives the output of the line memory (36), and a second field memory (37) which receives the output of the first field memory as an input. a field memory (38), a motion adaptive interpolation circuit (35) receiving the television signal, the output signals of the line memory (36) and the first field memory (37), and inter-field motion detection means (
1), interframe motion detection means (2) which receives the television signal and the output signal of the second field memory (38), and receives the television signal and the output signal of the line memory (36) as input. and mixes the output signals of the inter-field motion detection means (1) and the inter-frame motion detection means (2) according to the control signal from the control signal generation means, and outputs the output from the motion adaptive interpolation circuit. (35) A motion adaptive scanning line interpolation circuit, comprising: a mixing circuit (4) that supplies a signal to a motion-adaptive scanning line interpolation circuit.