JP2809726B2 - Video signal converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention converts a high-definition television signal having a larger number of scanning lines and an aspect ratio than a standard television signal into a standard television signal. To a video signal conversion device.

(Prior Art) TC as a high-definition television signal having a larger number of scanning lines and an aspect ratio than a standard television signal, and two color difference signals being line-sequential by a dot interlace method.
Some are encoded in the I method.

FIG. 7 shows a television signal converter for converting the high-definition television signal into a standard television signal.

A high-definition television signal is input to an analog-to-digital (hereinafter referred to as A / D) converter 11 via an input terminal 10,
It is converted to a digital signal. The input pattern of the luminance signal is dot-interlaced, for example, as shown in FIG. The solid line is the scanning line of the first field, and the position of the mark is the sub-sample phase position of the luminance signal. The dotted line is the second field, and the position of the triangle is the sub-sample phase position of the luminance signal. This signal is input to the input processing device 12, where processing such as de-emphasis processing is performed. The output signal of the input processing device 12 is input to the time axis conversion device 13. The time axis conversion device 13 is, for example, 11
25 lines / 60Hz, 1 horizontal scanning time of 2: 1 signal is 525 lines / 60Hz,
Since this is converted into one horizontal scanning time of a 1: 1 signal, this processing is performed commonly for the luminance signal and the color difference signal. Further, this output signal is supplied to a field interpolation and scanning line number conversion device 14.
, An interpolation process using the upper, lower, left and right data is performed, and the number of scanning lines is converted from 1125 to 525.

Here, the luminance signal Y and the chrominance signal C are further separated and input to the luminance signal D / A converter 16 to be converted into an analog signal. On the other hand, the chrominance signal C is input to the chrominance signal multiprocessor 17, where TCI decoding and time axis expansion are performed. That is, the chrominance signal is time-compressed during the horizontal blanking period of the luminance signal, is compressed to, for example, 1/4, and is multiplexed.
Since the (RY) signal and the (BY) signal are line-sequential, they are decoded.

The color difference signal C is expanded four times by the expansion device 17a,
Further, the (RY) signal and the (B-
Y) Interpolation is performed using upper and lower lines that are not present in the signal, and two color difference signals are synchronized. And (R-
The Y) signal and the (BY) signal are D / A converters 18a and 18 respectively.
Input to b and converted to analog signal.

According to the above method, as shown in FIG.
Lines / 60Hz Aspect ratio For example, remove the top and bottom lines and left and right signals from a 16: 9 high-definition
Conversion to a standard television signal with a 60Hz 4: 3 aspect ratio can be easily realized. Reference numeral 51 denotes a display screen, and a hatched portion is a truncated line.

(Problems to be Solved by the Invention) According to the above-mentioned conventional conversion device, the high-definition television signal 1125 lines / 60 Hz, the spectral ratio 16: 9, the fifth
As shown in the figure (B), the upper, lower, left and right are cut out and converted to a standard television signal of 525 lines / 60 Hz and an aspect ratio of 4: 3.
Therefore, according to this method, if important information is generally present in the peripheral portion of the screen, this is lost. Also, if important information is added to the center of the screen on the transmission side in consideration of this conversion and transmitted, a viewer watching a high-definition television signal may feel very unnatural. Further, converting a movie or the like by this method may cause a copyright problem.

Therefore, the present invention provides a video signal conversion device capable of performing conversion to a standard television signal without losing important information of a high-definition television signal and with a minimum hardware scale. Aim.

[Constitution of the Invention] (Means for Solving the Problems) The present invention relates to a high-definition television system which has a larger number of scanning lines than a standard television signal and in which two color difference signals are line-sequentially encoded by a time axis compression method. In a converter for converting a television signal into a standard television signal, an input signal processing means for performing a certain signal folding such as an interpolation process on a high-definition television signal, and an output signal of the input signal processing means for at least one horizontal signal A first delay unit for delaying a scanning time, an output signal of the input signal processing unit, an output signal of the input signal processing unit, and a color difference signal among the output signals of the first delay unit. A signal selection means for selecting and outputting an output signal, and for a luminance signal, selecting and outputting an output signal of the input signal processing procedure; and controlling the signal selection means. Control signal generating means for outputting a control signal for causing the signal selecting means to select a color difference signal from the delay means every n (n ≧ 1) horizontal scanning times, and a scanning line for an output signal from the signal selecting means Video signal converting means for converting the number into the number of scanning lines of the standard television signal by thinning out, and converting one horizontal scanning time into one horizontal scanning time of the standard television signal.

(Operation) By the above means, the line-sequential relationship of the color difference signals can be maintained by the control signal generating means and the signal selecting means even if the scanning line conversion processing device thins out the lines. , Compression can be performed without losing important information, and a luminance signal and a chrominance signal can be processed in common.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In this embodiment, the aspect ratio differs with a larger number of scanning lines than a standard television signal (for example, an NTSC television signal). In a dot interlaced system, two color removal signals {for example, a (RY) signal and a (B) signal are used. −Y) The signal｝ becomes line sequential,
A description will be given of an example of converting a high-definition television signal (for example, a MUSE television signal) encoded by the TCI method into a standard television signal. Also,
The display state after the conversion is as shown in FIG. 3 (A).

A high-definition television signal is input to the A / D
The signal is supplied to the converter 11 and converted into a digital signal. The sampling clock Φ1 here is, for example, Φ1 = 16.2 MHz.
It is.

The digitized signal is input to the input processing device 12 at the next stage, where processing such as non-linear expansion and de-enhance processing is performed. The output signal of the input processing device 12 is input to the aliasing removal / interpolation processing device 20.

In the aliasing removal / interpolation processing device 20, the input pattern of the luminance signal is dot-interlaced, for example, as shown in FIG. The solid line is the scanning line of the first field, and the position of the mark is the sub-sample phase position of the luminance signal. The dotted line is the second field, and the position indicated by the triangle is the sub-sample phase position of the luminance signal. This signal is subjected to an interpolation process using the data in the field, and is converted into a signal as shown in FIG. At the same time, aliasing components are removed by dot interlacing using a digital filter.

Next, the output signal of the aliasing removal / interpolation processing device 20 is
It is input to the pre-processing device 21.

The signal input to the preprocessing device 21 is supplied to the unit delay elements 212 and 213 via the unit delay element 211. The output signal of the unit delay element 212 is supplied to the selector 215 via the unit delay element 214. On the other hand, the output of the unit delay element 213 is supplied to the selector 215 via the unit delay element 217 after being delayed by one horizontal scanning period in the line memory 216. The selector 215 is controlled by a control signal CN1 from the synchronization control device 29, and continuously selects, for each three horizontal scanning periods, each color removal signal of the three horizontal scanning periods among the signals from the line memory 216 side, For signal, unit delay element 21
Select the one from 4 (the timing chart is shown in FIG. 2). The output of the selector 215 is the unit delay element 2
Output via 18.

FIG. 2 is a timing chart showing the operation of the pre-processing device 21.

FIG. 2A shows an output video signal of the unit delay element 214, which is supplied to one input unit of the selector 215. FIG. 11B shows a video signal output from the unit delay element 216 via the line memory 216, and is supplied to the other input section of the selector 215. There is a shift of one horizontal scanning period between the two video signals.

There is a period in which the control signal CN1 is at a low level corresponding to the position of the color-deleted signal at the timing shown in FIG. 9C. In this period, the selector 215 selects the signal on the unit delay element 216 side. Therefore, as shown in FIG. 2D, the video signal output from the selector 215 is output every 3 horizontal scanning periods.
The color difference signals in the horizontal scanning period are continuously present from the unit delay element 216 side, and the luminance signals are all selected from the unit delay element 214 side.

The output signal (FIG. 2 (D)) from the pre-processing device 21 is supplied to the scanning line number / time axis conversion device 30. The number-of-scanning-lines / time-axis conversion device 30 uses the field memory 31 to convert the number of scanning lines and the time axis. In other words, as shown in FIG. 5 (A), a portion that performs horizontal and vertical data compression so that a high-definition television signal having an aspect ratio of 16: 9 can be displayed on a display having an aspect ratio of 4: 3 without loss of information. It is.

Assuming that the number of scanning lines of a high-definition television in the vertical direction is, for example, 1032, this is thinned out at a ratio of one to three when viewed in frame units, and is reduced to 1/3, that is, a signal of 344 scanning lines. , And convert the rest to 688.

For this purpose, as shown in FIG. 2 (E), the control signal CN2 from the synchronization / control device 29 causes the 3rd horizontal scanning period.
One time at a time, the input image signal field memory 31
It is only necessary to prohibit writing to. As a result, the number of effective scanning lines is converted from 1032 lines to 688 lines. This writing process is performed simultaneously without discrimination between the luminance signal and the color loss signal.
The clock for this writing process is Φ2, and Φ2 =
32.4 MHz. This is the aliasing removal / interpolation processing device 2.
This is because, at 0, interpolation data is added as shown in FIG.

The signal written to the field memory 31 in this manner is
For example, it is read at a clock rate of 29.5 MHz. As a result, one horizontal scanning period of a high-definition television signal is converted to a time axis during one horizontal scanning period of a signal having 525 scanning lines and a 1: 1 interlace ratio (FIG. 2 (F)). Here, since the upper and lower 80 lines do not form an effective screen, there is no problem even if they are truncated at the time of memory reading.

This output signal is input to a luminance output processing device 32, where processing such as extraction of a luminance signal portion and addition of a blanking signal is performed in accordance with the specifications on the output side, and is converted into an analog video signal by a D / A converter 34. It is converted and derived to an output terminal. 2 (F) is also input to the color signal processing device 33. Here, the color removal signal is extracted. First, a color difference signal is written to the line memory and then read out with a clock having a period four times as long as the write clock. As a result, the color difference signal which has been compressed by a factor of 1/4 and which has been present in a part of one horizontal scanning period is restored to the original time (525 scanning lines, 1: 1
It is expanded during one horizontal scanning period of the interlace signal).

Further, since the (RY) signal and the (BY) signal are line-sequential as shown in FIG. 6, it is necessary to convert the color difference signal into sequential scanning. That is, for example, in line No. 2 in FIG. 6, only the (BY) signal exists,
The (RY) signal is interpolated and synthesized using the data of the upper and lower lines No. 1 and No. 3. In line No. 3,
The (RY) signal is used as it is for this line,
The (BY) signal is interpolated using signals existing in the upper and lower lines.

The color difference signal obtained in this manner is subjected to processing such as addition of a blanking signal in the same manner as the luminance signal, corrected to a signal conforming to the specifications on the output side, and output. The analog signal is output by the D / A converter 35. After that, the signal is derived to an output terminal.

The synchronization control device 29 in FIG. 1 generates the above-mentioned control signal, synchronizes the internal system clock with the input television signal according to the control signal of the high definition television signal, and outputs the same. A basic clock of the television signal is generated, and the television signal on the input side and the television signal on the output side are synchronized.

In the above description, the display mode of FIG. 5 (A) is shown. However, the present invention is not limited to this. For example, as shown in FIG. 5 (B),
It is needless to say that a display in which the upper and lower sides in the vertical direction and the left and right sides in the horizontal direction are cut can be realized.

Further, in this embodiment, when performing the interpolation processing as shown in FIG. 3, the interpolation is performed while weighting each interpolation data in the vertical direction. This is because, when the number of scanning lines is converted by thinning, the information above and below the thinned scanning lines is information of a position vertically separated,
The balance with the picture in the area where no thinning was performed will be shifted. In order to cover such a problem, vertical weighting processing is performed. Example 4
This will be described with reference to the drawings.

FIG. 4 (A) shows the arrangement position of the pixels (marked by ●) in the odd field and FIG. The X mark is the interpolated pixel. In this way, for example, the third line, the sixth line, the ninth line, etc. are weighted so that the upper and lower lines of the luminance signal of the thinned line are closer to the vertical direction (approximate the pattern of the upper and lower lines). Is performed, the picture at the time of the thinning-out processing is in a well-balanced compressed state as a whole. This can be understood by comparing the arrangement of the luminance signals in FIGS. 2 (D) and 2 (F).

According to this embodiment described above, the line-sequential relationship of the color difference signals can be maintained by the control signal generator and the signal selector even if the scanning line conversion processing device thins out the lines. In the thinning-out, when the same color difference signal exists at least between adjacent lines by the selecting means, one of the lines is thinned out. In addition, compression can be performed without losing important information by scanning line conversion processing by thinning, and the luminance signal and the chrominance signal can be processed in common.

[Effects of the Invention] As described above, the present invention can convert a high-definition television signal into a standard television signal without losing important information and with a minimum hardware scale. .

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a signal waveform diagram shown for explaining the operation of the circuit of FIG. 1,
FIGS. 3 and 4 are explanatory diagrams of a pixel arrangement for explaining the operation of the circuit of FIG. 1, FIG. 5 is a diagram showing an image display example obtained when a video signal is converted, and FIG. FIG. 7 is an explanatory diagram of a pixel arrangement for explaining the operation of the color signal processing device of the circuit of FIG. 1, and FIG. 7 is a circuit diagram showing a conventional scanning line and aspect ratio converting device. 11 A / D converter, 12 Input processing device, 20 Folding removal / interpolation processing device, 21 Preprocessing device, 30 Number of scanning lines / time axis conversion device, 31 Field Memory, 32 ...
... Luminance signal output control device, 33 ... Color signal output control device,
34, 35 ... D / A converter.

Claims (1)

(57) [Claims] 1. A converter for converting a high-definition television signal having a larger number of scanning lines than a standard television signal and encoding two color difference signals in a line-sequential manner by a time axis compression method into a standard television signal. An input signal processing means for performing a fixed signal processing such as an interpolation processing on a high definition television signal; a first delay means for delaying an output signal of the input signal processing means by at least one horizontal scanning time; The output signal of the input signal processing unit and the output signal of the first delay unit can be selectively output for the color difference signal among the output signal of the signal processing unit and the output signal of the first delay unit, and the luminance can be obtained. Signal selecting means for selecting and outputting an output signal of the input signal processing means; and controlling the signal selecting means to control the signal every n (n ≧ 1) horizontal scanning times. Control signal generating means for outputting a control signal for causing the selecting means to select a color difference signal from the delay means; and converting the number of scanning lines of the output signal from the signal selecting means into the number of scanning lines of a standard television signal by thinning. And
A video signal converting means for converting one horizontal scanning time into one horizontal scanning time of a standard television signal.