JPH0495479A - Tv display device for clear vision system - Google Patents

Abstract

PURPOSE:To reduce the apparent deterioration of the contrast of detailed information on a actual scanning line caused by the insertion of an interpolating picture element by, attenuating the luminance level of an interpolating scanning period when jump scanning is changed to progressive scanning. CONSTITUTION:Luminance data of an interpolating period from a mixer circuit 6 are written in a line memory 7 for double speed conversion after their amplitude is limited by means of an amplitude control circuit 12. The written luminance data are read out and given to a change-over switch 9 at a period 2fs and the luminance data of actual scanning lines time-compressed by a line memory 8 for double speed conversion and the luminance signals of an interpolating scanning period time-compressed by the memory 7 are alternately sent to a D/A converter 10. Converted luminance signals are outputted after quantization noise is removed by means of a low-pass filter 11 and a scanning line interpolated picture is displayed. When a small section of the picture is not clear, the viewer of this television display device turns on the key switch of a key switch group 13 while the viewer watches the picture displayed on the screen. A microcomputer CPU 14a reads out control data from a memory 14b and gives the data to the amplitude control circuit 12.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a clear vision television display device that performs scanning line interpolation on an interlaced scanning image signal to convert it into a progressive scanning format and display it. The present invention relates to a clear vision television display device with improved signal processing for moving parts.

[Prior Art] Recently, so-called clear vision television display devices have been actively developed that double the number of scanning lines to improve the quality of images.

FIG. 2 is a block diagram showing a conventional clear vision television receiver. In the figure, this television receiver includes a low-pass filter 1, an analog/digital converter 2 with a sampling frequency fs,
A luminance data/chrominance signal separation circuit 3, an intra-field scanning line interpolation circuit 4, an inter-field scanning line interpolation circuit 5, and a mixing circuit 6 for mixing the intra-field interpolated signal and the inter-field interpolated signal. , a line memory 7 for interpolation scanning lines for compressing the horizontal scanning period in half, a line memory 8 for actual scanning lines for compressing the horizontal scanning period in half, and a line for interpolation scanning lines. The actual scanning lines and interpolated scanning lines compressed by the memory 7 and the actual scanning line line memory 8 are processed by a clock 2 having a frequency twice the horizontal scanning frequency fH included in the NTSC composite signal.
A switching circuit 9 that performs time division multiplexing using fH, a digital/analog converter 10 that uses a period of 2 fs that is twice the sampling frequency f5, and a low frequency circuit that passes the analog signal converted by the digital/analog converter 10. filter 11.

The operation of the clear vision television receiver shown in FIG. 2 will be explained. The NTSC composite video signal is given to an analog/digital converter 2 after its frequency band is limited by a low-pass filter 1 . The analog/digital converter 2 converts the video signal into a digital signal using a sampling clock having a frequency f. The digital signal from analog/digital converter 2 is
The color signal component is removed by the luminance signal/color signal separation circuit 3. As a result, only the luminance signal component is extracted. The luminance signal extracted by the luminance signal/chrominance signal separation circuit 3 is applied to a field scanning line interpolation circuit 4, an interfield scanning line storage circuit 5, and a double speed conversion line memory 8.

The intra-field scanning line interpolation circuit 4 supplied with the luminance signal synthesizes interpolated scanning lines to be inserted between vertically adjacent actual scanning lines based on image information of scanning lines within the same field. Further, the interfield scanning line interpolation circuit 5
An interpolated scanning line to be inserted between vertically adjacent actual scanning lines in the current field is synthesized based on the image information of the scanning line one field before. The interpolated scanning line synthesized by the intrafield scanning line interpolation circuit 4 and the interpolated scanning line synthesized by the interfield scanning line interpolation circuit 5 are supplied to a pixel mixing circuit 6, and the pixel mixing circuit 6 performs intrafield scanning line interpolation. The interpolated pixels from the circuit 4 and the interpolated pixels from the interfield scanning line interpolation circuit 5 are mixed while changing the allocation according to the amount of movement of the current (current) pixel. Generally, the proportion of intra-field scanning line interpolation is increased in areas with a large amount of movement. The interpolated pixels mixed by the pixel mixing circuit 6 are input to the line memory 7 for double speed conversion.

The double speed conversion line memory 7 writes the input pixel data at a sampling frequency fs, and uses this written pixel data at a clock rate 2f which is twice the sampling clock fs.
By reading the input pixel information at s, the input pixel information is time-compressed and sent to the changeover switch 9.

The double-speed conversion line memory 8 that has received the brightness signal from the brightness signal/chrominance signal separation circuit 3 performs the same process as the double-speed conversion line memory 7 to read out the pixel data of the actual scanning line at a clock rate of 2 fs. Send it to changeover switch 9. In this way, by reading at twice the frequency of the analog-to-digital converter 2, the input image information can be time-compressed. This time-compressed image information is given to the changeover switch 9. Changeover switch 9 is NT
The time-compressed luminance signal of the actual scanning line and the time-compressed luminance signal of the interpolated scanning line are alternately sent to the digital/analog converter 10 at a period 2fH, which is twice the horizontal scanning period fH according to the SC method. A low-pass filter 11 removes quantization noise from the luminance signal converted into an analog signal at a clock cycle of 2 fs by the digital/analog converter 10 .

[Problems to be Solved by the Invention] However, conventional clear vision television display devices generate brightness signals for moving parts by mixing the scanning line of one field before and the scanning line of the current field. In principle, it is difficult to generate perfect interpolation pixels for moving parts. As a result, moving parts on the screen become unclear,
Making this moving part clearer has been a challenge for a long time.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a clear vision type television display device that can sharpen the contrast of moving parts.

[Means for Solving the Problems] A clear vision type television display device according to the present invention for achieving the above object is an analog/digital converter that converts an interlaced scanning image signal with a specified horizontal scanning frequency into an analog/digital format. digital conversion means; interpolation scanning line generation means for generating an interpolation scanning line based on an analog/digital converted current image signal and an image signal preceding the image signal; and generation by the interpolation scanning line generation means. amplitude suppression means for suppressing the luminance amplitude level of the interpolation scanning period during which the amplitude is suppressed; control means for controlling the amount of suppression of the amplitude suppression means; and luminance data included in the analog/digital converted image signal. , a first memory means written at the sampling frequency of the analog/digital conversion means and read out at a frequency twice the sampling frequency; and luminance data of the interpolation scanning period whose amplitude is controlled by the amplitude control means, a second memory means written at a sampling frequency of the analog/digital conversion means and read out at a frequency twice the sampling frequency; and luminance data read from the first memory means and the second memory. a selection means for alternately selecting the luminance data read from the means at a frequency twice the prescribed horizontal scanning frequency; and a selection means for alternately selecting the luminance data read from the selection means at a sampling frequency twice the analog/digital conversion means. and digital/analog conversion means for converting the signal into an analog signal.

[Operation of the Invention] In the present invention, the amplitude suppressing means suppresses the amplitude of the luminance signal during the interpolation scanning period from the interpolation scanning line generating means. This suppressed luminance signal is time-compressed by the second memory means and then transmitted to the selection means. The selection means is provided with data obtained by time-compressing the luminance data of the current time, that is, the actual scanning line, from the first memory means, and the selection means selects the luminance data from the first memory means and the luminance data from the second memory means. By alternately selecting brightness data at a frequency twice the horizontal scanning frequency, a high-density image formed by interpolated pixels whose brightness level is suppressed and pixels of the actual scanning line whose brightness level is not suppressed is created. Obtainable. In this case, the brightness level of the image by the interpolated pixels is suppressed by the amplitude suppressing means, so that the contrast of the image of the actual scanning line whose brightness level is not suppressed is apparently removed by the interpolated pixels. Can be suppressed. As a result, it is possible to suppress blurring of image parts that involve movement, that is, details of the image.

[Embodiment of the Invention] FIG. 1 is a block diagram showing an embodiment of a clear vision television display device according to the present invention. In addition,
In FIG. 1, parts similar to those in FIG. 2 are given the same reference numerals. The difference between this embodiment and FIG. 2 is as follows.
In order to lower the brightness level during the interpolation scanning period, an amplitude control circuit 12, a microcomputer 14, and a key switch group 13 are added. That is, the key switch group 13 includes a plurality of key switches 13a and 13b.

...Contains 13n. Multiple key switches 13a, 13
b, . . . 13n are switches operated by the operator when detailed parts of the image are unclear.

The microcomputer 14 includes an input port 14a connected to the key switch group 13, a memory 14b storing control data for controlling the amplitude control circuit 12,
an output port 14C connected to the amplitude control circuit 12a;
Input port 14a1 memory 14b and output port 14
The CPU 14d controls the CPU 14c. Amplitude control circuit 12
responds to a control signal from the microcomputer 14 to attenuate the luminance data from the pixel mixing circuit 6 during the interpolation period. Specifically, the brightness value from the pixel mixing circuit 6 is divided by the control data from the microcomputer 14. Alternatively, the control value is subtracted from the brightness value from the mixing circuit 6.

Hereinafter, the operation of the television display device of this embodiment will be explained as follows.
The explanation will be made with reference to the figures, but the explanation of the same operations as in Fig. 2 will be omitted as appropriate. The input NTSC composite received signal is band-limited by a low-pass filter 1 and then converted into a digital signal by an analog/digital converter 2. From the digitally converted composite video signal, only the luminance component is extracted by the luminance signal/chrominance signal separation circuit 3. This extracted luminance component is applied to a double speed conversion line memory 8, an intrafield scanning line interpolation circuit 4, and an interfield scanning line interpolation circuit 5.

The line memory 8 for double speed conversion time-compresses the input luminance data and supplies it to the changeover switch 9. The intra-field interpolation scanning line interpolation circuit 4 synthesizes interpolated scanning lines to be inserted between vertically adjacent actual scanning lines from image information of scanning lines within the same field. Further, the interfield scanning line interpolation circuit 5 synthesizes interpolated scanning lines to be inserted between vertically adjacent actual scanning lines in the current field from the image information of the scanning line one field before. Pixel mixing circuit 6
The interpolation pixels synthesized by the intra-field scanning line interpolation circuit 4 and the interpolation pixels synthesized by the inter-field scanning line interpolation circuit 5 are mixed by changing the allocation according to the amount of movement of the current pixel.

The operation up to this point is the same as the conventional example. The luminance data during the interpolation period from the mixing circuit 6 is given to the amplitude control circuit 12, where the amplitude is limited.

The brightness data whose amplitude has been controlled by the amplitude control circuit 12 is
The signal is given to the double speed conversion line memory 7 and written into the double speed conversion line memory 7. The written luminance data is 2
It is read 8 at a period of fs and applied to the changeover switch 9.

The changeover switch 9 alternately switches the luminance data of the actual scanning line time-compressed by the line memory 8 for double-speed conversion and the luminance signal in the interpolation scanning period time-compressed by the line memory 7 for double-speed conversion to the digital/analog converter. 10
send to The luminance signal converted into an analog signal by the digital/analog converter 10 is outputted after removing quantization noise by a low-pass filter 11.

An image subjected to scanning line interpolation based on this output luminance signal is displayed. If the details of the displayed image are unclear, the operator turns on a desired key switch from the key switch group 13 while looking at the television screen. In response to turning on the key switch, the microcomputer's CP
U14a reads control data from memory 14b and provides it to amplitude control circuit 12 through output port 14c. The amplitude control circuit 12 attenuates the luminance data input from the pixel mixing circuit 6 during the interpolation scanning period based on control data from the microcomputer 14 . This attenuated luminance data is converted into a luminance signal through a path of double speed conversion line memory 7→changeover switch 9→digital/analog converter 10→low-pass filter 11. Screen display is performed based on this converted luminance signal. As described above, the operator can attenuate the brightness level during the interpolation scanning period by operating the key switch group while looking at the screen. As a result, it is possible to suppress details of the image from becoming unclear due to the high brightness level during the interpolation scanning period.

In the above embodiment, only the luminance signal of the interpolated scanning line is attenuated, but the color signal may also be attenuated in conjunction with this.

Furthermore, in the above embodiment, the luminance signal is output after digital/analog conversion, but in the format where RGB signals (red, green, blue) are output after digital/analog conversion, the RGB signals of the interpolated scanning lines are A method may be used in which the attenuation is performed, or a method in which the luminance component of the interpolated scanning line is attenuated.

Furthermore, a method may be used in which the luminance signal of the interpolated scanning line is set to a complete black level.

Furthermore, instead of connecting the key switch group to the microcomputer, a transmitter is provided to the key switch group,
The microcomputer may be provided with a receiver to remotely control the amplitude control circuit.

In addition, in the above embodiment, an NTSC system composite signal is used as an input signal, but instead of this system, PAL,
It is also possible to use a composite signal of other systems such as SECAM as an input signal.

[Effects of the Invention] As described above, according to the present invention, it is possible to attenuate the luminance level during the interpolation scanning period when interlaced scanning is converted to progressive scanning. Therefore, it is possible to improve the contrast of detailed information on the actual scanning line from appearing distorted due to the insertion of interpolation pixels.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing a conventional example. In the figure, 1 is a low-pass filter, 2 is an analog/digital converter, 3 is a luminance signal/chrominance signal separation circuit, 4 is an intra-field scanning line interpolation circuit, 5 is an inter-field scanning line interpolation circuit, and 6 is a pixel mixing circuit. circuit, 7 and 8 are line memories for double speed conversion, 9 is a changeover switch, 10 is a digital/
11 is a low-pass filter, 12 is an amplitude control circuit, 13 is a key switch group, and 14 is a microcomputer.

Claims (1)

[Claims] Analog/digital conversion means for converting an interlaced scanning image signal with a specified horizontal scanning frequency from analog to digital; an analog/digital converted image signal at the current moment; and an image preceding this image signal. interpolated scanning line generating means for generating an interpolated scanning line based on the signal; amplitude suppressing means for suppressing a luminance amplitude level during the interpolating scanning period generated by the interpolating scanning line generating means; and the amplitude suppressing means. control means for controlling the amount of suppression; and luminance data included in the analog/digital converted image signal are written at a sampling frequency of the analog/digital conversion means and read out at a frequency twice the sampling frequency. and the luminance data of the interpolation scanning period whose amplitude is controlled by the amplitude control means is written at a sampling frequency of the analog/digital conversion means and read out at a frequency twice the sampling frequency. a second memory means that alternately reads the luminance data read from the first memory means and the luminance data read from the second memory means at a frequency twice a prescribed horizontal scanning frequency; A clear vision television display device comprising: a selection means for selecting; and a digital/analog conversion means for converting luminance data from the selection means into an analog signal at a sampling frequency twice that of the analog/digital conversion means.