JPH0225599B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to an improvement in an apparatus for converting a composite video signal based on interlaced scanning such as the NTSC system into a progressive scanning system video signal. Background technology Standard television system (NTSC system, SECAM system)
(PAL, PAL, etc.), the luminance signal and chrominance signal are composite signals that overlap on the frequency axis.
The resolution of the luminance signal decreases in the horizontal and vertical directions, making it impossible to obtain sufficiently good image quality. Also,
Interlaced scanning is used, which causes phenomena such as line flicker interference, pairing interference, and deterioration of image quality due to scanning lines being viewed separately. As a countermeasure, the luminance signal and the color signal are separated based on the correlation between frames and between scanning lines, and an interpolated signal is obtained by line interpolation and field interpolation.
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 the luminance signal and color signal from the interlaced scanning composite video signal based on the correlation between frames. When obtaining the scanning line interpolation signal for each color, a delay of 1V 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. In addition, there are 4 memories each with a capacity of 1V.
A method has also been proposed in which only one element is used, but this is a slight reduction of one element compared to five, and in practice this has the drawback that the simplification of the configuration and the reduction in cost are still insufficient. . DISCLOSURE OF THE INVENTION The present invention has an object of fundamentally eliminating such drawbacks of the conventional art, and in the above-mentioned apparatus, each of the devices is sequentially connected in series from the input side giving a delay of 1 V to the composite video signal. The input of the first delay element and the output of the second delay element are added, the summed output is provided to the interpolation signal generator, and the interframe signal is output from each similar output. The amount of change in the video is determined and fed to the motion detector, while the luminance signal and color signal are separated from the output of the first delay element based on the correlation between scanning lines, and the delay is 1V. The present invention provides an extremely effective progressive scan conversion device that uses only two delay elements, simplifies the configuration, and reduces manufacturing costs. Therefore, according to the present invention, the required number of delay elements providing a 1V delay is significantly reduced, and
The overall configuration is simplified, the device cost can be easily reduced, and a remarkable effect can be obtained in conversion to a progressive scanning method. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be explained in detail 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.
A/D)1 converts it into a digital signal,
It is applied to the first and second feed memories 2a and 2b connected in series sequentially from the input side each having a capacity of 1V, and in each, 1V
Since writing and reading are performed with a time _difference of At the same time, the second field _F2 is sent to the output, and the result of the third field _F3 is obtained to the input of the same memory 2a, resulting in the state shown in FIG. 2 as an example of the situation of each field. The input/output of the field memory 2a and the output of the field memory 2b are given to a luminance signal separation circuit consisting of subtracters 4, 5 and a bandpass filter (hereinafter referred to as BPF) 6. In the case of the NTSC system,
Since the phase of the color subcarrier is reversed for each frame, if the composite video signal of field F ₁ and the composite video signal of field F ₃ belonging to the next frame are fed to the subtracter 4, there will be no change in the video. When the luminance signal is canceled out, the chrominance signal is added as a result, and the chrominance signal appears at the output of the subtracter 4, which has a passing frequency of 3.58 MHz for the purpose of noise removal etc. BPF6
After the signal becomes only the exact signal, it is sent to the subtracter 5, where the color signal is canceled against the composite video signal of field _F2 . A separate luminance signal Y _RF is generated from the composite video signal of field F ₂ based on the correlation. In addition, the output of the field memory 2a is given to a Y/C separator 7 which separates the luminance signal _YRL based on the correlation between scanning lines, where the coefficients are separated from the luminance signal YRF together with the separated luminance signal _YRF . Coefficient that is given to adder 8 and increases when the video is a moving image
K _YC (0≦K _YC ≦1) is multiplied to the luminance signal Y _RL , while the coefficient 1 - which increases when the video is a still image
K _YC is multiplied by the luminance signal Y _RF , and both are added and sent out as a luminance signal Y _R for sequential scanning. Therefore, in the case of a still image, each scanning line Sa ₁ to F 3 of fields F ₁ and F ₃ is
Based on the correlation between Sa ₄ and Sb ₁ to _{Sb 4} , a color signal component is extracted, and the color signal component is subtracted from the information of this scanning line using scanning lines Sa ₂₆₃ to _{Sa 266} as a reference, thereby obtaining a signal for sequential scanning. A luminance signal Y _R indicating the scanning lines J ₁ , J ₃ , J ₅ , and J ₇ is obtained. Note that the scanning lines Sa ₁ to Sa ₄ , Sb ₁ to _{Sb 4} and Sa ₂₆₃ to
There is a difference of 0.5H (H is the period of one scanning line in the interlaced scanning method) from Sa ₂₆₆ , which results in an error of one scanning line of information when converted to sequential scanning, but it is approximate Since the conditions are considered to be essentially the same, there is no problem in practical use even with the above-mentioned processing. On the other hand, the input of the field memory 2a and the output of the field memory 2b are added by an adder 9, and are given to the interpolation signal generator 11 as an addition output containing a luminance signal 2Y of twice the value.
Here, an interpolated luminance signal Y _I for sequential scanning is generated based on the luminance signals Y _R and 2Y,
This is used to display the scanning lines J ₀ , J ₂ , J ₄ , and J ₆ shown in FIG. Also, the output of the subtractor 4 is the field F ₁ and F ₃
It indicates the change in the image between the 3.58MHz and 3.58MHz.
LPF) 12, the luminance signal change ΔY is extracted from the output of the adder 4, and the luminance signal 2Y from the adder 9 is supplied to the differentiating circuit 14.
4 to obtain differential values DY of the luminance signal, and these are supplied to the motion detector 15. The motion detector 15 detects changes in the video between frames based on the change amount ΔY and the differential value DY, and determines whether the screen is a moving image or a still image, or
Depending on whether these intermediate states exist, the coefficient K _YC , 1
_- After determining the values _{of K YC} , 1-K For _YC , as mentioned above,
The addition ratio of the luminance signal Y _RL and Y _RF is determined, and the coefficient
Depending on K _L and K _H , the luminance signals Y _R and 2Y of the interpolated luminance signal Y _I generated by the interpolation signal generator 11
The degree of dependence on The luminance signal Y _R and the interpolated luminance signal Y _I are provided to a time axis converter 16 using a memory etc.
The color signal C _RL from the Y/C separator 7 is converted into a color signal C _R for sequential scanning in the line interpolator 17, and the interpolated color signal C _I based on the color signal C _RL is generated within the line. These data are sent to the time base converter 18 using a memory or the like, and are sequentially stored at the scanning speed of the interlaced scanning method, and sent out at twice the speed. The color signal C and the luminance signal Y of the progressive scanning system are applied to the matrix circuit 19, where they are combined into a three-color video signal for each hue, and then sent to a digital-to-analog converter (hereinafter referred to as D/A).
A) The signals are converted into analog signals by 20a to 20c and sent out as R, G, and B color video signals. A pulse generator 21 is provided to obtain clock pulses CK including ADC/A/D sampling clocks and horizontal/vertical synchronization signals HD, VD from the composite video signal ICS, and is synchronized with the color subcarrier. It generates various clock pulses CK having a frequency that is an integral multiple of the frequency, and also generates a horizontal synchronization signal HD and a vertical synchronization signal VD in synchronization with each synchronization component of the composite video signal ICS, and supplies them to each necessary part. ing. In addition, the line interpolator 17 includes a delay element with a delay of 1H, an adder, etc., and interpolates the color signal C _I based on the correlation between scanning lines.
The motion detector 15 is based on the ``Television Society Technical Report'' (TEBS83-4, Showa
It is sufficient to use the circuit disclosed in P19-P24 published on September 27, 1957, and any known circuit can be applied. FIG. 3 is a block diagram of the coefficient adder 8.
Luminance signals separated based on correlation between scan lines
For Y _RL , coefficient unit 3 such as a programmable attenuator
At the same time, _the luminance signal _YRF separated based on the correlation between frames is multiplied by a coefficient K
-K _YC is multiplied, and the outputs of each coefficient multiplier 31 and 32 are added by an adder 33 to obtain a luminance signal _YR for sequential scanning.
By increasing K _YC , increasing the coefficient 1 - K _YC for a still image, changing both coefficients in a complementary manner, and selecting both coefficients according to the degree of movement when the screen is in an intermediate state. , the dependence of the luminance signal Y _R on the luminance signals Y _RL and Y _RF is determined. In other words, when it is a still image, there is no change in the brightness for each frame, and the brightness signal Y _RF can be used as the brightness signal Y _R , but when it is a moving image, the brightness changes for each frame, and the brightness signal Y RF is used as the brightness signal Y _RF. If you _use
In the intermediate state between a still image and a moving image, it is necessary to mix the luminance signals Y _RL and Y _RF at a suitable ratio depending on the _degree of movement to generate the luminance signal Y _R. These operations are realized by the configuration shown in FIG. 3. FIG. 4 is a block diagram of the interpolation signal generator 11, in which the luminance signal _YR is generated by line memories 41a to 41c connected in series, each having a capacity of 1H.
Since writing and reading are performed with a time difference of 1H in each, a delay of 1H is given by each line memory 41a to 41c, and the input and output of line memory 41b are as follows. In addition to being added by an adder 42, a coefficient unit 4 such as a programmable attenuator is added.
The input of the line memory _41a and the output of the line memory 41c are added by an adder 44, and then multiplied by a coefficient _KL2 by a similar coefficient unit 45.
The outputs of 3 and 45 are added by an adder 46 and then given to an adder 47. On the other hand, the luminance signal 2Y is transmitted from the line memory 41a to
Line memory 4 connected in series similar to 41c
8a and 48b, and a delay of 1H is given to each by the same operation as described above, and the input of line memory 48a and the output of line memory 48b are added by adder 49 and then , are multiplied by the coefficient K _H1 in the same coefficient multiplier 50 as described above, and the line memory 48a
The output of is also multiplied by a coefficient K _H0 by a similar coefficient multiplier 51, and the outputs of the coefficient multipliers 50 and 51 are added together by an adder 52, and then added to the output of the adder 46 by an adder 47. , is sent out as an interpolated luminance signal Y _I. Here, the luminance signal 2Y is the field
It is the sum of F ₁ and F ₃ , and as shown in Figure 2, paying attention to these scanning lines Sa ₁ to Sa 3 and Sb ₁ to _{Sb 3 ,} Sa ₂
And if Sb ₂ is a ₀ , Sa ₁ , Sa ₃ and Sb ₁ , Sb ₃ are a ₁ , then a luminance signal of 2a ₀ , which is twice each of these luminance values, is generated at the output of the line memory 48a, and the same
A luminance signal indicating 2a ₁ will appear at the input of line memory 48a and at the output of line memory 48b. Furthermore, the luminance signal Y _RL indicates scanning lines J ₁ , J ₃ , J ₅ , and J ₇ for sequential scanning as shown in FIG.
If J ₃ and J ₅ are b ₁ and J ₁ and J ₇ are b ₂ , a luminance signal indicating b ₁ is generated at the input and output of the line memory 41b, and a luminance signal indicating b ₂ is generated at the line memory 41.
This occurs at the input of a and the output of the line memory 41c. Therefore, by adding these at a predetermined ratio, the luminance signal b 0 indicating the interpolated scanning line J ₄ can be obtained, and by continuously performing this operation, the luminance signal b ₀ indicating the interpolated scanning line J ₀ , J The luminance signals for ₂ and _J6 are obtained in the same way. However, each coefficient varies depending on whether the image screen is a moving image, a still image, or an intermediate state.
Select K _L1 , K _L2 , K _H0 , K _H1 and interpolate luminance signal Y _I
If it is necessary to control the synthesis situation of a complete still image or a complete moving image and divide it into four stages M ₁ to M ₄ , each coefficient may be determined as shown in the table below, for example.

[Table] Note that the line memories 41a to 41c to the adder 46 are
It forms an LPF and is involved in the generation of an interpolated luminance signal Y _I to reduce the resolution and reduce double image interference occurring in the moving area of the screen. Further, the line memories 48a, 48b to the adder 52 form a similar HPF (high frequency filter), and are involved in the generation of the interpolated luminance signal _YI to improve the resolution in the static area of the screen. There is. FIG. 5 is a block diagram of the Y/C separator 7, in which a well-known Y/C separator 61 such as a 1H delay element type or a 2H delay element type generates a luminance signal Y _RL based on the correlation between scanning lines. The color signal _CRL is separated from the color signal CRL, and each of them is sent out via a switch 62, while a color signal detection circuit 63 monitors whether or not a color signal is included in the composite video signal of field _F2 . This detects the color width carrier wave component, and operates the switch 62 to the Y/C separation circuit 61 side based on the detection output. However, when the color subcarrier wave disappears due to a black and white composite video signal, this Accordingly, the detection power also disappears, the switch 62 is restored to the input side, and the composite video signal of the field _F2 is sent out as it is as the luminance signal _YRL . 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. Since only two memories 2a and 2b are required and the overall configuration is simplified, the device can be manufactured at low cost. 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.
a, 2b, line memories 41a to 41c, 48
The same effect can be obtained by replacing a, 48b, etc. with various delay elements such as an ultrasonic delay line or a CCD.
It is also optional to configure the entire circuit with an analog circuit without using the D/A 20a to 20c. In addition, the color signal C _R and the interpolated color signal C _I are extracted based on the correlation between frames, as well as the luminance signal Y _R and the interpolated luminance signal Y _I. A coefficient adder adds the color signal C _R as a ratio according to the movement of the screen.
At the same time, an interpolated color signal C _I may be determined using an interpolation signal generator. In addition, in FIG. 4, the number of line memories 41a to 41c, 48a, and 48b is determined according to the number of used scanning lines a ₀ , a ₁ , b ₁ , b _{2 ,} etc. shown in FIG. Therefore, all you have to do is select the surrounding configuration. Figure 5 shows a _YC separator to maintain the vertical resolution when inputting black and white signals. The present invention can be modified in various ways, such as using only the /C separation circuit 61.

[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 a coefficient adder, and Fig. 4 is an interpolation signal generation. FIG. 5 is a block diagram of a Y/C separator. 2a, 2b...field memory (delay element),
4, 5...Subtractor, 6...BPF (bandwidth filter),
7... Y/C separator, 9... Adder, 11... Interpolation signal generator, 15... Motion detector, ICS... Composite video signal, R, G, B... Each color video signal.

Claims (1)

[Claims] 1. In a device for converting an interlaced scanning composite video signal into a progressive scanning video signal based on correlations between frames and between scanning lines, each input side provides a delay of one field to the composite video signal. A first delay element 2a and a second delay element 2b are sequentially connected in series from 1st
a subtracter 4, a bandpass filter 6 that extracts a color signal from the output of the first subtracter, and an addition signal obtained by adding the input of the first delay element and the output of the second delay element. an adder 9 that outputs, a separation circuit 7 that separates a first luminance signal and a color signal from the output of the first delay element based on the correlation between scanning lines, and a separation circuit 7 that separates a first luminance signal and a color signal from the output of the first delay element. a second subtracter 5 that subtracts the color signal extracted by the bandpass filter and outputs a second luminance signal; and a second subtracter 5 that inputs the change in the video and the differential value of the added signal to generate a moving image portion of the video. A motion detector 1 outputs video information for luminance signal separation and video information for luminance signal interpolation that increase according to the amount of motion.
5, a coefficient adder 8 which inputs the first and second luminance signals and the video information for luminance signal separation and outputs a luminance signal for progressive scanning, and the luminance signal for progressive scanning, the addition signal, and the luminance signal. an interpolation signal generator 11 that inputs interpolation video information and outputs an interpolation luminance signal; a line interpolator 17 that inputs the color signal and outputs a progressive scanning color signal and an interpolation color signal;
A luminance signal time axis converter 16 that inputs the progressive scanning luminance signal and the interpolated luminance signal and sends out a progressive scanning luminance signal in which the progressive scanning luminance signal and the interpolated luminance signal are alternately horizontally scanned. and a color signal time axis conversion which inputs the progressive scanning color signal and the interpolated color signal and outputs a progressive scanning color signal in which the progressive scanning color signal and the interpolated color signal are alternately horizontally scanned. 1. A progressive scan conversion device characterized in that a converter 18 is provided.