JPH0228957B2 - TEREBIJONSHINGOHENKANHOSHIKI - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to an improvement in a method for converting a composite video signal using interlaced scanning such as the NTSC method into a progressive scanning video signal. [Background technology] In standard television systems such as the NTSC system, SECAM system, and PAL system, the luminance signal and chrominance signal are overlapping signals on the frequency axis. Separation means for separating both signals using a separation method produces cross colors or lowers the resolution of the luminance signal in the horizontal and vertical directions, making it impossible to obtain sufficient image quality, and because an interlaced scanning method is used. Based on this, phenomena such as line flicker interference, pairing interference, and the fact that scanning lines are viewed separately have resulted in deterioration of video quality. As a countermeasure for this, the luminance signal and color signal are separated based on the correlation between frames and scanning lines, and an interpolated signal is obtained by line interpolation and field interpolation, and one field period of interlaced scanning (hereinafter referred to as
In V), it was proposed to perform sequential scanning corresponding to one frame of interlaced scanning after supplementing the interpolated signal, and a progressive scanning conversion device was proposed to convert an interlaced scanning composite video signal into a progressive scanning video signal. It is about to be developed. However, the conventional method requires a delay of 2V when separating a luminance signal and a chrominance signal from an interlaced scanning composite video signal based on the correlation between frames, and also requires a delay of 2V. , B, a delay of IV is required for each color, and when digital processing is used, the delay is 1V.
It is necessary to provide as many as five memories each having the same capacity as the conventional one, which makes the configuration complicated and expensive. As a countermeasure for this, the present applicant has separately applied for a ``television signal converter'' (patent application filed in 1983-
164322), which proposes a means for realizing equivalent functionality using only two field memories each having a capacity of 1V. In addition, in this means, the first and second field memories are provided in series from the input side, and the luminance signal and the color signal are separated from the output of the first field memory based on the correlation of the scanning lines. together with the input of the first field memory and the input of the second field memory.
A luminance signal is separated from the output of the field memory based on the correlation between frames, an interpolated luminance signal is generated according to each separated luminance signal, and the correlation between the interpolated luminance signal and the scanning line is generated. The luminance signals separated based on the relationship are applied to a time-base compressor, and these signals are sequentially sent out from the time-base compressor as luminance signals for sequential scanning. Therefore, in this configuration, the field in which luminance signals are separated based on the correlation between scanning lines is different from the field in which the luminance signals are separated based on the correlation between frames. If the degree of correlation is low, the states of the respective fields do not match, and the luminance signal separated based on the correlation between scanning lines and the interpolated luminance signal do not necessarily correspond, resulting in double image disturbance. Additionally, if the color signals between scanning lines have a low degree of correlation, the color signal components will mix into the luminance signal, and the luminance signals separated based on the correlation between the scanning lines will cause dot-like interference on the image plane. arise. [Disclosure of the Invention] The present invention has been made in view of the above drawbacks of the conventional technology, and provides a television signal conversion method that reduces each of the above-mentioned interferences even when the above-mentioned respective degrees of correlation are low. The purpose is to provide In order to achieve this objective, in the present invention,
A first and a second delay element each giving a delay of 1V to the composite video signal are sequentially connected in series from the input side, and a first Y/C separator is connected to the input of the first delay element. The luminance signal and the chrominance signal are separated based on the correlation between scanning lines, and the second Y/C separator separates the input of the first delay element and the output of the second delay element between frames. Separating a color signal based on the correlation, and separating a luminance signal from the input of the first delay element using the color signal, and extracting it from the input of the first delay element and the output of the second delay element. The movement of the image is detected by a motion detector based on the brightness signal and the amount of change thereof, and then the coefficient adder detects the first
and the respective luminance signals from the second Y/C separator are multiplied by complementary coefficients and then summed, the output of which is sent to a time base compressor for the luminance signal, while the detection output of the motion detector is control the switch according to the
The color signal from the first Y/C separator is switched to the color signal from the first Y/C separator, and this output is sent to a time axis compressor for color signals. Therefore, according to the present invention, the first and second
In both Y/C separators, the luminance signal is separated from the input of the first delay element, and
Since the luminance signals from the first and second Y/C separators are added complementarily according to the movement of the image, the field where the luminance signals from the first and second Y/C separators were present is At the same time, the luminance signals from the first and second Y/C separators are used together, so that the dot-shaped disturbance does not occur when the image is stationary, and the occurrence of double image disturbance is reduced. Significant effects can be obtained in conversion to scanning mode. [BEST MODE FOR CARRYING OUT THE INVENTION] The details of the present invention will be explained below with reference to figures showing examples. FIG. 1 is a block diagram of the entire configuration, showing a case where an NTSC composite video signal is given as an interlaced scanning composite video signal ICS. D) converted into a digital signal by 1,
It is applied to the first and second field memories 2a and 2b connected in series sequentially from the input side each having a capacity of 1V.
Writing and reading are performed according to the time difference. For this reason, each field memory 2a to 2b
A delay of 1V is given sequentially,
The first field is output from field memory 2b.
When F ₁ is sent, field memory 2
The second field F ₂ is sent to the output of memory 2a, and the third field F ₃ is sent to the input of the same memory 2a.
The state is given by Note that this state is as illustrated in FIG. 2 as an example of the situation of each field. The input of the field memory 2a is given to a first Y/C separator 3 that separates a luminance signal _YRL and a color signal _CRL based on the correlation between scanning lines, while
The input of the field memory 2a and the output of the field memory 2b are applied to a subtracter 4, where a change ΔF in the composite video signal between fields _F1 and _F3 is extracted, and this signal is applied to the second field. Frequency of color subcarrier forming Y/C separator 5
Bandpass filter (hereinafter referred to as BPF) that passes 3.58MHz
6, the color signal _CRF is separated based on the correlation between frames. Furthermore, since the color signal C _RF is given to the subtracter 7, and the composite video signal from the input of the field memory 2a is also given to the reducer 7, the color signals in the composite video signal are canceled here. , the luminance signal _YRF is separated based on the correlation between frames. Therefore, if we focus only on the luminance signal, the second
As shown in the figure, the luminance signal Y _RL is separated from the scanning lines S _b1 to S _b4 of field F ₃ , and the frame
A luminance signal Y _RF is separated from frame F ₃ based on the correlation between F ₁ and F ₃ , and these are added according to the movement of the image to produce a luminance signal Y _R. If the scanning images J ₁ , J ₃ , J ₅ , J ₇ can be displayed, and the interpolated luminance signal Y _I is generated based on the luminance signal Y _R , the scanning lines J ₂ , J ₄ , J ₆ and J ₈ can be displayed. Furthermore, frames F ₃ and F ₁ are frames of the same order in adjacent fields, and scanning lines S _a1 to S _a4 and S _b1 to _{S b4} have the same phase and the highest degree of correlation. The scanning lines S _a263 to _{S a266} of frame F ₂ , which have a different phase from these, are used as the respective luminance signals Y _R and Y _I
Since each luminance signal Y _R , Y _I
Therefore, even if the scanning lines J ₁ to J ₈ are displayed as the same frame, the possibility of double image interference is extremely reduced. However, when the video is moving rapidly, the luminance signal Y _RL separated from the scanning lines S _b1 to S _b4 is used as the luminance signal Y _R because the correlation between frames is low, and when the video is stationary, the frame It is a good idea to use the luminance signal Y _RF separated from the scanning lines S _b1 to _{S b4} based on the correlation between frames as the luminance signal Y _R , and the color signals C _RL and C _RF as well. It will be the same. Therefore, from the change ΔF from the subtractor 4, the change ΔY in the luminance signal is extracted via a low-pass filter (hereinafter referred to as LPF) 10 that passes the frequency band below 3.58 MHz, and this is sent to the motion detector. 8, and add the input of the field memory 2a and the output of the field memory 2b by the adder 9,
After extracting the luminance signal 2Y, which has doubled in value, it is also fed to the motion detector 8, which detects the motion of the image, and uses this detection power to switch the switch 1.
1. It controls the coefficient adder 12 and the interpolation signal generator 13 to perform the operations described above. That is, the switch 11 includes the Y/C separator 3.
When the video is in a static state, the color signal C _{RF is} selected and sent to the time axis compressor ₁₄ for color signals. When the detection power CC of the detector 8 occurs, the color signal C _RF is switched to C _RL in response to this, and this is sent to the time axis compressor 14 . Further, the coefficient adder 12 is given luminance signals Y _RL and Y _RF from the Y/C separators 3 and 5,
According to the detected power of the motion detector 8 indicating the coefficients K _YC and 1-K _YC , the respective signals Y _RL and Y _RF are added as complementary ratios and sent to the time axis compressor 15 for the luminance signal. . Note that the addition ratio of the color signals Y _RL and Y _RF is such that the signal Y _RF is large when the image is stationary, and the signal Y _RL is large when the image is moving rapidly. On the other hand, the interpolation signal generator 13 has coefficients K _H1 , K _H2 ,
It is controlled by the detection power of the motion detector 8 indicating K _L1 and K _L2 , and generates an interpolated luminance signal Y _I based on the luminance signal Y _R , and the signal Y _I is stored in the memory etc. along with the luminance signal Y _R. It is applied to the time axis compressor 15 used. Further, the interpolated color signal C _I is generated in the interpolated signal generator 16 based on the color signal C _R , and is also provided together with the color signal C _R to the time-base compressor 14 using a memory or the like. Therefore, these signals are accumulated sequentially at the scanning speed of the interlaced scanning method, and are also sent to the matrix circuit as the color signal C and luminance signal Y of the progressive scanning method from the time axis converters 14 and 15 at twice the speed. 19, where it is synthesized into three-color video signals for each hue, and then converted into analog signals by digital-to-analog converters (hereinafter referred to as D/A) 20a to 20c, and R, G, and B signals are combined. Each color is sent out as a video signal. In addition, the clock pulse from the composite video signal ICS
A pulse generator 21 is provided to obtain CK and horizontal and vertical synchronizing signals HD and VD, and generates various clock pulses CK that are synchronized with the color subcarrier and have a frequency that is an integral multiple of this frequency.
A horizontal synchronization signal HD and a vertical synchronization signal VD are generated in synchronization with each synchronization component of the composite video signal ICS, and are supplied to each section that requires them. In addition, the motion detector 8 is equipped with a
The circuit disclosed in the Japanese publication, pages 19 to 24) may be used. FIG. 3 is a block diagram of the Y/C separator 3, and the composite video signal of field _F3 is 1H each.
(H is the period of one scanning line) is applied to the line memories 31a and 31b connected in series, and since writing and reading are performed with a time difference of 1H, each line memory 31a, 31b respectively give a delay of 1H, and these inputs and outputs are added by adders 32 and 33, and
Further, the adder 34 adds the luminance signals, and the mutually in-phase luminance signals become four times the value, while the color signals, which are in opposite phases for each adjacent scanning line, are canceled out. Only the luminance signals are extracted, and then the coefficient multiplier The signal is multiplied by a coefficient of 1/4 by 35 and sent out as a luminance signal _YRL separated based on the correlation between scanning lines. Further, the input and output of each line memory 31a, 31b are subtracted by subtracters 36, 37, and further subtracted by subtracter 38, and contrary to the above, the color signal becomes 4 times the value, After the luminance signal is canceled and only the color signal is extracted, it is multiplied by a 1/4 coefficient by the coefficient unit 39 to produce the same color signal as described above.
Sent as _CRL . FIG. 4 is a block diagram of the modulation adder 12, which multiplies the luminance signal _YRL separated based on the correlation between the scanning junctions by a coefficient _KYC using a coefficient unit 41 such as a programmable attenuator. , the luminance signal Y _RF separated based on the correlation between frames is multiplied by a coefficient 1 - K _YC by a coefficient unit 42 similar to the coefficient unit 41, and these outputs are added to the adder 4.
3 to form the luminance signal _YR . In addition, when the image is in a moving state, the coefficient K _YC is set large,
When the image is in a stationary state, the coefficient 1 - K _YC is set large, and both coefficients are changed complementary to each other. When the image is in an intermediate state, both coefficients are selected according to the degree of movement, and the luminance signal Y _R is changed. The degree of dependence on each signal Y _RL and Y _RF is determined. FIG. 5 is a block diagram of the interpolation signal generator 13, in which the luminance signal Y _R is sent to a field memory 51 which provides a delay of 1V, a half line memory 52 which provides a delay of 0.5H, and a field memory 52 which provides a delay of 0.5H, and a field memory 52 which provides a delay of 0.5H, and a field memory 52 which provides a delay of 1H, respectively. It is applied to a series circuit of line memories 53a and 53b that provide a delay, and is also applied to a series circuit of line memories 54a to 54c that each provide a delay of 1H, and as shown in FIG. 6 showing the waveforms of each part, the current field When a is given as the luminance signal Y _R , the immediately preceding field b is generated at the output of the field memory 51, and field c, which is delayed by 0.5H, is generated at the output of the half line memory 52. Therefore, when scanning line J _a1 of field c occurs at the output of line memory 53b, scanning lines J _a3 and J _a5 of field c occur at the output and input of line memory 53a, while line memory 54
A scanning line J _b1 of field a is generated at the output of field a, and correspondingly, each output of the line memories 54b and 54a and the input of the same memory 54a are output from the field a.
The scanning lines J _b3 , J _b5 , and J _b7 are generated. Here, since the luminance signal Y _R is extracted from the interlaced scanning composite video signal, there is a phase difference of 0.5H between fields a and b.
By inserting the half line memory 52, the phases of fields a and b match, and these scanning lines J _a1 , J _a3 ,
If a composite value is calculated from the luminance signal values of J _a5 and J _b1 , J _b3 , J _b5 , and J _b7 , each scanning line can be converted to the scanning line J ₁ ,
When corresponding to J ₃ , J ₅ , J ₇ , scanning line J ₄
An interpolated luminance signal Y ₁ indicating . Therefore, the input of the line memory 53a and the output of the line memory 54b are added by an adder 55, multiplied by a coefficient K _H2 by a coefficient unit 56 such as a programmable subtracter, and the same is applied to the output of the line memory 53a. A coefficient K _H1 is multiplied by a coefficient multiplier 57, and these outputs are added by an adder 58, while an input and an output of the line memory 54b are added by an adder 59, and a coefficient K _L1 is multiplied by a similar coefficient multiplier 60. At the same time, the input of the line memory 54a and the output of the line memory 54c are added to the adder 61.
and the coefficient K _L2 is added by a similar coefficient unit 62.
After multiplying by , these outputs are added by an adder 63, and the output of this and the output of the adder 58 are added by an adder 64, and the result is sent out as an interpolated luminance signal _YI . However, each coefficient K _H1 ,
It is necessary to select K _H2 , K _L1 , and K _L2 and control the synthesis situation of the interpolated luminance signal Y _I. When a completely stationary to moving state is divided into four stages M ₁ to M ₄ , for example, It is sufficient to set each coefficient as shown in the table below.

[Table] Note that the line memories 54a to 54c to the adder 63 are
It forms an LPF and is involved in the generation of the interpolated luminance signal _Y1 , thereby reducing the resolution and reducing double image interference occurring in the moving area of the screen. Furthermore, the line memories 53a, 53b to the adder 58 form a similar HPF (high frequency filter), and are involved in the generation of the interpolated luminance signal _Y1 to improve the resolution in the static area of the screen. There is. Therefore, by continuously performing the above operations, interpolated luminance signals indicating scanning lines J ₂ , J ₆ , J ₈ , etc.
Y _I can be found in the same way. FIG. 7 is a block diagram of the interpolation signal generator 16. The color signal C _R is applied to a line memory 71 which provides a delay of 1H, and its input and output are interlaced scanning type. Color signals of adjacent scanning lines are generated, and these are added to the adder 72.
After adding the value to double the value, the coefficient unit 7
It is multiplied by a coefficient of 1/2 by 3 and sent out as an interpolated color signal C _I. Therefore, the interlaced scanning composite video signal ICS
is converted into sequential scanning color video signals R, G, B corresponding to one frame of this, and sent to a video display circuit etc. with 1V of the composite video signal ICS corresponding to one frame. From _F3 , the luminance signal _YRL is separated based on the correlation between scanning lines, and the luminance signal _YRF is separated based on the correlation between frames, and these are sent to the coefficient adder 12.
is added as a ratio according to the movement of the image to obtain the luminance signal Y _R for sequential scanning, and based on this, the interpolated luminance signal Y _I is generated, reducing double image interference. At the same time, dot-shaped disturbances do not occur except when the video is in motion. In addition, the color signal C _RL separated based on the correlation between scanning lines and the color signal C _RF separated based on the correlation between frames are obtained, and these are selected according to the movement of the image. Therefore, the fidelity of color display is improved. However, the composite video signal ICS is not limited to the NTSC format, but any other format can be applied as long as one frame is composed of two fields. In addition, field memories 2a, 2b, 51, line memories 31a, 31b, 53a, 53b, 5
4a to 54c, 71 and the half line memory 52, etc., can be replaced with various delay line elements such as ultrasonic delay lines or CCDs.
It is also optional to configure the entire circuit by an analog circuit without using a to 20c. Note that the interpolated color signal _C1 may also be obtained using an interpolated signal generator that performs the same processing as the interpolated luminance signal _Y1 . In addition, in FIG. 5, the number of line memories 53a, 53b, 54a to 54c is determined according to the number of used scanning lines _J1 , _J3 , _J5 , _J7, etc. shown in FIG. Therefore, it is only necessary to select the peripheral configuration, and the configurations shown in FIGS. 3 and 7 can be arbitrarily selected as long as they have equivalent functions, and various modifications can be made.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, Fig. 1 is a block diagram of the entire configuration, Fig. 2 is a diagram showing the status of each field, Fig. 3 is a block diagram of the Y/C separator, and Fig. 4 is a coefficient diagram. A block diagram of the adder, FIG. 5 is a block diagram showing an interpolation signal generator for luminance signals, FIG. 6 is a diagram showing waveforms of each part in FIG. 5, and FIG. 7 is an interpolation signal generator for chrominance signals. FIG. 2a, 2b...field memory (delay element),
3, 5... Y/C separator, 4, 7... Subtractor, 6
...BPF (bandwidth filter), 8...Motion detector, 9
... Adder, 10 ... LPF (low frequency filter), 11
...Switch, 12...Coefficient adder, 13, 16
...Interpolation signal generator, 14, 15...Time axis compressor, ICS...Composite video signal, Y _RL , Y _RF , Y _R , 2
Y... Luminance signal, ΔY... Variation, Y _I ... Interpolated luminance signal, C _RL , C _RF , _CR ... Color signal, C _I ... Interpolated color signal.

Claims (1)

[Claims] By supplying color signals and luminance signals extracted based on correlations between frames and between scanning lines to a time-base compressor equipped with an interpolation signal generator, the interlaced scanning method is realized. In a television signal conversion method for converting a composite video signal of 1 to a video signal of a progressive scanning method, first and second a second delay element; a first V/C separator that separates a luminance signal and a chrominance signal based on the correlation between scanning lines from the input of the first delay element; and the first delay element and a second delay element for separating a chrominance signal from the input of the first delay element and the output of the second delay element based on the inter-frame correlation, and separating a luminance signal from the input of the first delay element by the chrominance signal. a C separator; a motion detector that detects motion of an image based on a luminance signal extracted from the input of the first delay element and the output of the second delay element and a change in the luminance signal; a coefficient adder that multiplies each luminance signal from the first and second Y/C separators by complementary coefficients according to the detection power of the detector, adds them together, and sends the result to a time axis compressor for luminance signals; , Switching the color signal from the second Y/C separator to the color signal from the first Y/C separator according to the detection power of the motion detector and sending it to a time axis compressor for color signals. A television signal conversion system characterized by comprising a switch for