JPS6149575A - Scanning converter - Google Patents

Abstract

PURPOSE:To obtain pictures of high resolution by obtaining a TV signal in the successive scanning system consisting of a video signal in the current field and an interpolating signal generated from the video signal in the current field or the preceding field in accordance with presence/absence of variation of the picture signal. CONSTITUTION:A read signal (h) from a field memory 2 is delayed by a 1/2H delay circuit 3 and is supplied as a signal (i) to one input of a selector 6. Signals (h) and (i) are added by an adder 4 and are averaged by a coefficient device 5 to obtain a signal (j), and this signal is supplied to the other input. The selector 6 is so controlled that the signal (i) is selected if absence of the variance is discriminated by a variance detecting circuit 8 and the signal (j) is selected if presence of the variance is discriminated, and a signal (k) is outputted from the selector 6. This signal (k) is subjected to D/A conversion by a D/A converter 7, and an average value signal of lines adjacent to each other in the same field is obtained as the interpolating signal, thereby improving the picture quality.

Description

[Detailed Description of the Invention] 4) Industrial Application Field The present invention converts a television signal transmitted in an interlaced scanning system into a progressive scanning television signal, and eliminates various problems of the interlaced scanning system such as line flicker. Regarding a scan conversion device for eliminating alignment and reproducing high-quality images, in particular, when there is no movement in the image of the input video signal, interpolation signals are obtained from adjacent fields, whereas when there is movement, relates to a scan converter in which an interpolated signal is obtained from a signal within the current field.

(Explanation) Conventional technology: Receiving an interlaced scanning television video signal and interpolating between the scanning lines using an interpolation signal, the field @ wave number is the same as in the interlaced scanning method, but the total number of scanning lines is doubled. High-definition television receivers are being considered.

By the way, the NTSC television currently broadcast in Japan (1) each rJ, 1/, the number of scanning lines is 2 every 60 seconds.
62.5 field signals are interlaced scanned and sent, and 2 fields constitute a frame signal with 525 scanning lines, so the video signals of 2 different fields are combined every 1760 seconds. When configuring a single frame image, a high-definition image with twice the number of scanning lines can be obtained if the image is stationary or has little movement, but if the image changes significantly over time, This is a composite of two images that moved for 1,760 seconds, which degrades the image quality. Using the information, the number of scan lines? By obtaining a doubled image, using all the scanning lines in the same field in areas with large image movements, and performing the entire process of doubling the number of scanning lines, the deterioration of image quality due to movement is suppressed. A scan converter in this manner is described in Japanese Patent Laid-Open No. 77375/1983.

The device described in this publication is equipped with two different signal sequences for obtaining interpolated signals, and selects one of the signals obtained from these two signal sequences as the image content (with or without motion).
(no movement) to obtain an interpolated signal,
The above-described processing is performed by subjecting the interpolated signal and the input signal to time-base conversion.

However, the scan conversion device described in this publication requires a separate time axis conversion circuit, which not only makes the configuration extremely complicated, but also has disadvantages in that it is disadvantageous in terms of cost and lacks practicality.

p-+ Opening Points to be Solved by the Invention As described above, the present invention provides a scan conversion device that performs all scan conversion processing in accordance with the presence or absence of image movement, with a simple configuration and at low cost. It is constructed as a means for solving all the problems, and the video signal field frequency for two fields in the interlaced scanning method is the same, but the number of lines is doubled. A/S device for converting the video signal of the progressive scanning system into a television picture signal of the interlaced scanning system, the N+ of the video signal of the interlaced scanning system
A record U["JQ having an address corresponding to one line, a control means for controlling the reading and writing of this storage device, and a motion detection means for detecting the presence or absence of an image of a predetermined level or higher are provided. , the 11 control means circulates the addresses for the N+1 lines of the device described in 1. above, and sequentially writes video signal information and sound for each line in each field of the video signal of the interlaced scanning method. With,
The motion detecting means [If no motion is detected, the control means receives the video signal information of the previous field written to the address of one line of the storage device, and then the video signal information of the previous field written at the address of one line of the storage device, The video signal information of the current field written to the address is read out at twice the writing speed,
When the motion detection means detects that there is movement,
The same video signal information of the current field written to the address of one line of the storage device by the control means is read f1 by repeating all writing speed') 2 times 0 speed Δ twice.

(E) Effect If configured as above, when it is determined that there is no movement in the image, the first half of the first line of the current field will be skipped to the One line of information in the previous field is read out during one horizontal period of scanning, and the second half M! (The operation of reading out one line of information of the current field being written during the period is repeated. Then, if it is determined that there is movement of the image, one line of the current field is read out.
While writing information for a line, the first half of the line
During the H-off period, the information for one line immediately before this line is read, and during the latter %'H period, the information of the current field being written is read.
The operation of reading information is repeated for each line □ (f) Example The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a block diagram showing an embodiment of the scan conversion device of the present invention, and U+ represents a signal obtained by demodulating a television signal transmitted in an interlaced scanning method (for example, a Y signal, An A/D converter 121 converts the output signal into a digital signal 1g+, and 121 is a field memory for writing or reading the output signal from the A/D converter+11, and as described later, it is a field memory for approximately one field. It is configured to have storage capacity.

+31 is the output signal (hl
%H delay memory for delaying 4H (one horizontal period in interlaced scanning to H); (4) C. Adds the output signal 1hl of the field memory 12+ and the output signal (1) of the %H delay memory (31). an adder (51 is the adder (4)
), which has the function of multiplying the addition result obtained from the coefficient multiplier bt- by a coefficient bt-; , selector (7) is the output signal of the selector (6) (01B, which is a D/A converter' that converts it into an analog signal mark and outputs it to a display device (not shown)).
A motion detection circuit that detects the presence or absence of movement of an image by a predetermined amount or more by obtaining an interframe difference signal from the A/D converter force signal 1gl! Yes, the corresponding test tj3 circuit +81
Depending on the output of the field memory (2), the control circuit (91) that controls the operation of the field memory (2) and the selector +61 are controlled as will be described later.

Next, the above field memory (operation of 21?Table/wasu 2nd
The operation of this embodiment will be explained with reference to the timing chart shown in the figure and FIG. 3 showing the output signal waveform diagram of each part in FIG. 1.

In FIG. 2, (A) is a schematic diagram showing the waveform of a video signal on a television layer that performs 2:19H1g over-scanning,
For convenience of explanation, the ratio of the vertical scanning period to the horizontal scanning period is set to 7.5.
:1, and each line of the first and second fields is given a code such as the item number. Also, the same figure -
2 is a timing chart showing the operation of the field memory (27) in relation to the above signal waveform, the vertical axis represents the address of the field memory, the horizontal axis represents the time, and the solid line represents writing, and the broken line represents Each readout is shown.

2N+1 In the present invention, each field a has a total field frequency of one line (N is a natural number, in the case of this example (CN = 7J), and the video signal for two fields in an interlaced scanning relationship with each other). The field memory (2) is provided with addresses for lcN+1 lines (in this example, 8 lines λ) for a fixed-scan television signal with the same number of lines and twice the number of lines. The circuit A9 cycles through all the 8247 addresses and writes the video signal information for each line in each field.This write operation is performed by the motion detection circuit (8). Regardless of the detection output of ff1J, there is no difference between the case of no movement and the case of movement, but the read operation is different between the cases of movement and no movement.

During the T1 period in FIG. 2(b), the motion detection circuit (81
The read state of the field memory when motion is detected by the T1 period. If no excitation is detected in (8), read operation vi-period T of the memory 121 controlled by control means (9). t″
To explain using an example, this period T. LK, while writing to the address of one line of video signal sound a' of the existing second field, the video signal a of the previous field (first field) that has already been written to the address of this one line is written in the first half. It is first read out at AH, and then the corresponding period T is read out.

The video signal a' written in is controlled to be read out in the second half QH. The read speed at this time is 2 times the write speed.
It is controlled by the surface control circuit 191 so that it is doubled.

By doing so, the signals of each line of the two fields are read out alternately between 3-MHM and time-base compressed.

Next, when the motion detection circuit IFII I/c↓ detects that there is movement, the reading operation of the memory (2) controlled by the control circuit (91vc) will be explained by taking the period T2 as an example. C of the second field present in
A video signal? While writing to an address for one line, the current field written to the address for one line immediately before the address for one line (b' of the second field)
The video signal is read in the first half of the glaze H period at twice the writing speed, and then the video signal C' written in the period T2 is read out in the second half of the %m period at twice the writing speed of '4F. Control to read. By doing this, when there is movement, an interpolation signal is created using only the video signal information of the current field (second field in the illustrated embodiment), and is read out after being time-base compressed.

By controlling the field memo 2) in this way, the video signal information (hl) read from the field memory 12) during the period T3 in FIG. 2 becomes as shown in FIG. T if there is movement.

Since the interpolation signal is created by fully using only the video signal of the current field, deterioration in image quality due to image movement is reduced. Therefore, it may be configured such that the signal is directly supplied to the D'/A converter (7) as shown in FIG. In other words, the signal read from the field memory 121 (FIG. 3 [C]) is processed by the H delay memory + 31 VC to convert the signal to H (H plus one horizontal period in the interlaced scanning method). In other words, it becomes a delayed signal Lit (51st EIt port) corresponding to one line of the signal read out from the field memory 12?, and is supplied to one input and 1- of the selector (6). The other input of (6) is supplied with the signal 1hl, the signal 111, and the signal 1jl [FIG. 3 (c)] averaged by the full adder (4) and the coefficient unit (51).
The selector 161 selects VCf so that the motion detection circuit (8) selects the signal (il from 1 to 1) when it is determined that there is no movement, and selects the signal +jlk when it is determined that there is movement.
As a result, the selector +61 outputs a signal (kl c in Figure 3), which is supplied to the D/A converter (7), ), the signal 111 converted to an analog video signal is deflected at a horizontal deflection frequency that is twice that of the interlaced scanning method and a vertical deflection frequency that is the same as that of the interlaced scanning method. A sequential scanning screen is formed.In this way, the interpolation signal created during the TiC period can already be obtained as an average value signal of adjacent lines in the same field, so the image quality can be further improved. □In addition, in Fig. 5, for example, the signal b'+c' indicates the average value of the signal C. Also, in this device, the signal b'+c' is treated as a digital signal converted from A/D. Therefore, it is not possible to display the waveform in the video signal information as shown in Fig. 2 and Fig. 6, but for convenience of explanation, it is expressed as an analog 1 gray image signal. According to the invention, when the movement of an image grows, as shown in period T in FIG. If a scanning television signal is obtained and there is no image motion force 1, a progressive scanning television signal consisting of an interpolated signal consisting of the video signal in the current field and the video signal of the previous field is obtained. As a result, it is possible to configure a high-resolution image with little deterioration in image quality, and at the same time @B/fEm
Since the k-field memory is controlled by 4nVc, the configuration as a scan conversion station can be simplified and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the scan conversion device of the present invention, FIG. 2 is an explanatory diagram of its operation, and FIG. 3 (inside the signal waveforms of each part in the block diagram of FIG. (storage device), (81...Motion detection circuit, f9+...1; Control circuit.

Claims (1)

[Claims] (1) Progressive scanning television video in which each field consists of (2N+1)/2 fins, and two fields of video signals in an interlaced scanning relationship have the same field frequency and double the number of lines. A device for converting into a signal, comprising: a storage device having addresses corresponding to N+1 lines of the interlaced scanning video signal; a control means for controlling writing and reading of the storage device; A motion detection means for detecting the presence or absence of motion is provided, and the control means cycles through the addresses of the N+1 lines in the storage device, and detects video signal information for each line in each field of the interlaced scanning video signal. are sequentially written, and if no motion is detected by the motion detection means, the video signal information of the previous field written to the address of one line in the storage device by the control means, and the following The video signal information of the current field written to the address for one line is read out at twice the writing speed, and if the motion detection means detects that there is movement, the control means reads out the video signal information of the current field written to the address for one line. The same video signal information of the current field written to the address of the line is read out twice at twice the writing speed, and the video signal information of each line obtained one after another by each reading is sequentially read out. A scan conversion device characterized in that it obtains a television signal.