JPS58175379A - Converting circuit of color television signal - Google Patents

Abstract

PURPOSE:To obtain a high-precision color picture which is free from the quality deterioration of a dynamic picture, by picking up the pictures of both the 1st and 2nd fields at the same time point. CONSTITUTION:When the signal supplied to an input terminal 1 is under the 4th scan, the output of a field memory 2 is equal to a signal of the 3rd scanning line. The output of a subtractor circuit 3 passes through a 1/2 coefficient circuit 4 and a BPF5 and is turned into carrier color signals corresponding to the 3rd and 4th scanning lines. These color signals are demodulated by a color demodulating circuit 10 to obtain two types of color difference signals IQ34. Then the color difference signals IQ2 and IQ3 underwent the linear interpolation and corresponding to the 2nd and 3rd scanning signals are obtained between the signal TQ34 and a color difference signals IQ12 which is delayed by a delay line 12. At the same time, luminance signal Y3, Y4 and Y2 are obtained from the carrier color signals supplied from the BPF5. These obtained signals Y2, Y3, IQ2 and IQ3 are supplied to a time axis compressing circuit 15 to receive the 1/2 compression. This output of compression is switched by a switching circuit 18 and in a field period and then delivered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color revision signal processing circuit, and more particularly to a color revision signal processing circuit that doubles the number of scans (481) and reproduces a high-definition single image.

The NTSC color television signals that are currently in practical use use 2:1 interlaced scanning, and in order to obtain high-definition reproduced images, the so-called scanning system that simultaneously displays the signals of the scanning lines of the previous field is used. When the doubling process is performed,
When the subject moves, the edge portion becomes double-sided, resulting in deterioration in image quality. To improve this, there is a method that switches the signal processing method for scanning at 412 times by determining the presence or absence of movement of the subject, but this has problems such as the processing circuit becomes complex9 and there is some deterioration in image quality. There is.

One way to solve this problem is to perform sequential scanning without interlace on the camera side, and scan one frame with odd numbers 1.
A scanning line doubling method is known in which the field image is divided into several 4A scanning edges and transmitted as a field image gIA format, and the scanning line tube of adjacent fields within the same frame is simultaneously displayed on the receiving side.

In case of color television signal, accurate brightness 1 at J receiving side
If the color signal tIIA1j- is not performed, the mixing of both signals will generate rolls, dot crawls, false color signals, etc., which will offset the image quality improvement effect of the scanning line doubling process.

When scanning @ doubling, which is performed sequentially on the camera side, is applied to a color television signal, the above-mentioned The effect of improving image quality will be canceled out. On the other hand, if the luminance signal and chrominance signal are separated using the difference signal between adjacent frames, ideal luminance and one color separation can be performed.
Deterioration occurs when the subject moves. Therefore, motion-adaptive luminance two-color separation processing is required, which complicates the circuit and leaves some image quality deterioration.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a signal processing circuit with a simple configuration that provides high-definition color 1IIII images without deterioration in image quality.

In order to achieve the above object, in the signal processing circuit of the present invention,
The difference between the scanning lines of the first field and the second field (adjacent scanning lines M on the screen in which the polarities of the carrier color signals are reversed to each other) of the NTSC system color television signal input and forming the frame. NT
An interpolated scanning line signal is created over one frame period in the SC format, and its time axis is compressed to 1/2, so that the number of scanning lines whose horizontal scanning period is y1/2 in the NTSC format is It is characterized by converting into a doubled color television signal. That is, the color television signal is captured by a camera using a progressive scanning method without interlacing, and the next color television signal is
The first scan line is divided into odd scan lines and even scan lines. The second field is constructed and then converted into an interlaced television signal, and converted into a signal format that conforms to the NTSC system, which is the current television broadcasting standard. In the fcNT8C signal processed in this way, the images of the first field and the second field constituting the frame are iii+* taken at the same time, and even if careful processing is performed between the fields, the image of the subject will be No changes in characteristics occur due to movement. Therefore, by inputting all of this NTSC signal to the above-mentioned conversion circuit, it is possible to obtain a high quality color television signal in which the problems of the conventional system are solved.

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

FIG. 1 shows the basic operation 1FrI! of the signal conversion circuit of the present invention. 5
This is a time chart that shows the results. In the figure, ■ indicates a time chart covering a 7-frame period in imaging, ■ in transmission, and ■ in image reception. When photographing, the device scans the image from top to bottom at a frame period of 1/30 seconds without interlacing 525 lines. The obtained video signal is divided into odd-numbered scanning lines and even-numbered scanning lines in order to maintain consistency with existing TV joy equipment, and is interlaced in units of frames as shown in Figure 1. When this signal is scanned and converted into a good signal form and displayed on a conventional television receiver, two identical images taken every 1/30 seconds are displayed for each field.

In the NTSC color television signal, the polarity of the color subcarrier signal is inverted every horizontal scanning period H. 1st
In Figure 3, the first scanning line and the second scanning line of the next field are separated by 263H, so the inertia of the conveyed color signal is reversed. Therefore, the lever on the image receiving side is Q both legs 31. When the difference between the lines is calculated, this difference signal includes a carrier color component and a vertical variation component of the luminance signal. By extracting the carrier color signal component t in this difference signal using a bandpass filter (BPF), the color signal component can be separated from the NTSC signal by n degrees.

If the luminance signal and chrominance signal are separated in this way and then time-compressed to 1/2 using a time-base compression circuit, 525 scanning lines will be included in one field period (1/60 second) of the NTSC signal. You can get high definition television signal format. The second field is also separated in the same way as the 5g17 frame, and then, for example, the first field. The second scanning line luminance signal and color signal are used to create a second field high-n fine television signal. Converted high-definition television signals are the first
As shown in FIG. 3, in the case of the non-internorsing progressive scanning method, the second field of the NT8C signal is converted into the same signal as the first field, and the number of frames is doubled to 60 frames/second. On the other hand, when converting to interlaced high-definition television, the second field scans the middle of the first field, so the upper and lower scans adjacent to W4 -
Find a new scanning line signal by interpolating from .

FIG. 2 shows one implementation of the conversion circuit of the present invention for converting to a non-interlaced high definition television signal. In the figure, a color television signal converted to an interlaced scanning system similar to the signal (2) in FIG. 1 is input to an input terminal 1. The input signal U263H is also input to the friend field delay memory 2 having a capacity t', and the difference with the field delay output is subtracted times w! 13. When the signal input to the input terminal is the fourth scan in FIG. 1, the output of the field memory is the signal of the third scan line. The output of the subtraction circuit 3 is passed through a 1/2 coefficient circuit 4 and a bandpass filter 5, and is then output to the third . The carrier color signal corresponds to the fourth scanning line (the polarity r'i of the subcarrier signal is the same as that of the fourth scanning line). By demodulating this with t color demodulation circuit IO, 2
A seed color difference signal IQ34 is obtained. On the other hand, the input signal, that is, the color signal conveyed from the oil field, which is the output of BrF3, is passed through the delay circuit 6.7 (the delay time is equal to the calculation delay time of BrF3), that is, the third. If the addition (subtraction) circuit 8.9 adds and subtracts the composite color television signal -1 of the fourth scanning line, the third. Luminance signal Y3°Y4 corresponding to the fourth scanning line
is obtained.

The two types of color difference signals IQ34 obtained by the color demodulation circuit IO are converted into the third color difference signal IQ34. The average value of the color difference signals of the fourth scanning line is the average value of the color difference signal of the fourth scanning line, and its center of gravity is the third. This is the middle position of the fourth scanning line. Therefore, in relation to the color difference signal IQ12 (average value of the color difference signals of the first and second scanning lines) delayed by the delay line 12 having a delay time of the horizontal scanning period (H), .1
By applying a load inversely proportional to the distance ratio by 4, the linearly interpolated color difference signal I corresponding to the second and third scanning lines is obtained.
Q2. You can get an IQ of 3. That is, IQ2=(
3XIQ12+IQ34)/4IQ3=(IQI2+3
XIQ34)/4 Fourth scanning line luminance signal Y4tLH When passed through the delay circuit 11, a second scanning line luminance signal Y2 is obtained as shown in FIG.

The second person attended. 3rd scan - luminance signal 1 color difference signal Y2.
Y3. IQ2. Input IQ3 to the time axis compression circuit 15,
The time axis is compressed to 1/2, multiplexed in units of scanning lines, and signals Y and IQK are sequentially converted. This is converted into three primary color signals R1G and BK by the Marx circuit 16, and 525H (
7) Delayed with 7V-4 memory 17 with capacity 7t3m
The color signal and the 1NT8c signal are switched in field period units by the switching circuit 18, and the output screen 19 has 525 scanning lines as shown in Figure 1C, 3 primary colors at 60 frames/sec. The f6 signal is output twice over the 17-nom period of the original NT8C signal. - FIG. 3 shows another embodiment with the same No. 18 conversion output t as in FIG. 2. In this figure, circuits with the same symbols as those in FIG. 2 have the same functions.

The configuration shown in FIG. 2 requires a field memory 2 for storing a composite color television signal having a capacity t of 263H and a frame memory 17 for storing 525H of three primary color signals g. The arrangement of FIG. 3 reduces this memory requirement, t, by providing field memories 2 and 20, which store 263H of composite color television signals, to perform all desired signal conversions over one frame period. The operation will be described below.

In FIG. 3, the field memory 20 with a capacity of 263H is divided into two memories 201 and 202 with a delay capacity of 2625H and 0.5H. For the delayed nine signals and seven n et al.
6Z5H) Prepare the delayed signal. By switching these with the changeover switches 21 and 22 every field period, the signals of the next scanning line pair 263H111 within the same frame are obtained every two field periods. Therefore, with the same circuit configuration as in Fig. 2, the power supply circuit 8°9,
As the output of the color demodulation circuit 10, the third. Luminance signal Y3 corresponding to the fourth scanning embroidery. Y4 and two types of color difference signals IQ34 are obtained. In addition, an IHM extension circuit 11 having the same configuration as in FIG.
12, Coefficient product-sum circuit j1813゜14, Time axis compression circuit 1
5. The time axis is compressed to 1/2 by the matrix circuit 16 to the p output terminal 19, and the number of scanning lines is doubled to 525.
A progressively scanned, 60 frames/second television signal is obtained.

In addition, in FIGS. 2 and 3, the output I of the color demodulation circuit lO
Q34'i 3rd. 2nd line color difference signal IQ3 of the fourth scanning line.
By using IQ4, the lH delay circuits 12 and 13 and the coefficient product-sum circuits 13 and 14 can be omitted, and the circuit configuration can be simplified.

Second. In the example shown in Fig. 3, we have described the case where the signal is scanned in a progressive scanning mode at 60 frames per second.In the second field, for example, the average between the scanning edges of the converted RlG and To output the value with a delay of 174 times the horizontal scanning period H of the NTSC signal, it is possible to output 1049 lines of interlaced scanning, 60 fields/second, 30 frames/second of interlaced scanning television. I can get a signal. In this case, the first field ri26175H
By adjusting the delay of the p1 vertical synchronizing signal by H/4 in this manner, the interlaced 1iII image can be displayed correctly on the monitor. Also, if you change it, 1. Interlaced signal 't- with equal second field synchronization
Obtainable. By adjusting this variable axis, it is possible to convert the signal into an interlaced television signal with n scanning lines.

According to the present invention, by using the signals of the scanning lines of the same frame shot at the same time,
- and scanning line correction rlI11t - are performed, so that not only a still image but also a moving image can be obtained with a high ffa color image without image quality deterioration due to movement. In addition, as mentioned in the embodiment, a conversion circuit can be realized on the same scale as a conventional still image processing circuit, which eliminates the need for complex processing circuits such as motion determination and processing mode switching based on motion. This can be very effective in reducing the cost of conversion circuits.

[Brief explanation of the drawing]

FIG. 1 is a time chart diagram explaining the present invention in detail, and FIG. FIG. 3 each shows a configuration diagram of an embodiment of the signal conversion circuit of the present invention.

Claims (1)

[Claims] Using the signal of one frame of NT8C color television signal, the luminance signal and carrier color corresponding to the inner rectangular scanning line are determined from the difference signal of the scanning edges of adjacent fields in the same frame from nine adjacent scanning lines on the display screen. The time axis t is compressed to y1/2 by a time compression circuit, and the signals 1f-, i! of the inner rectangle f# are separated from the signals 1f-, i! Convert to f41 signal sequentially and convert to NTS
1. A color television signal conversion circuit characterized in that the circuit converts a C signal into a television signal having twice the number of scanning lines over one frame period.