Television – Format conversion – Specified chrominance processing
Reexamination Certificate
1999-07-08
2001-10-23
Kostak, Victor R. (Department: 2711)
Television
Format conversion
Specified chrominance processing
C348S450000
Reexamination Certificate
active
06307592
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for processing a TV video signal, and more particularly, to a video signal format converting apparatus for doubling a horizontal/vertical frequency, and converting the composition ratio of a luminance signal to a color-difference signal, by which both horizontal/vertical frequency-converted and frequency-unconverted input signals can be processed.
2. Description of the Related Art
In a conventional digital TV signal processing method, flickering phenomenon or resolution is improved by converting a digital TV signal into a video signal whose vertical frequency is doubled by double scan conversion, or converting the digital TV signal into a video signal whose horizontal frequency is doubled by progressive scan conversion.
Three signals, luminance information Y and color-difference information U and V, are included in a pixel constituting a horizontal line (scanning line) of a TV screen or the like, and are represented by certain ratios according to the amount of information in the signals. That is, when the amount of color-difference information is not reduced, the three signals are represented by the ratio of 4:4:4. When the amount of color-difference information is halved in the horizontal direction, the three signals are represented by the ratio of 4:2:2. When the amount of color-difference information is reduced to one quarter in the horizontal direction, the three signals are indicated by the ratio of 4:1:1.
In particular, in the case of 4:4:4, the amount of data in each of the luminance signal and the color-difference signals is the same, and one luminance signal and two color-difference signals correspond to one pixel. Since, there is a larger amount of data in the ratio of 4:4:4 than in the other composition ratios, the quality of the image is increased.
As shown in
FIG. 1
, according to the prior art, a signal decoded by a decoder
101
has a composition ratio of 4:1:1 or 4:2:2. Thus, a horizontal/vertical frequency converter
102
is needed, which doubles the horizontal/vertical frequency of the decoded signal, using a progressive scan conversion method or a double scan conversion method.
Next, a format converter
103
converts the scanning-converted video signals having a composition ratio of 4:1:1 or 4:2:2 into signals having a composition ratio of 4:4:4 to improve the image quality of the video signals, and outputs the resultant signals to a multiplexer
104
.
R, G, and B analog input signals are converted into digital Y, U, and V signals, having the composition ratio of 4:4:4, by an analog-to-digital (A/D) converter
105
and a space converter
106
, and the digital Y, U, and V signals are output to the multiplexer
104
.
Then, the multiplexer
104
selects and outputs the converted external input signals or an internally-processed signal according to a control selection signal.
According to the prior art as described above, external R, G, and B input signals received from a personal computer or the like are progressive scan converted or double scan converted. Only a signal having a doubled horizontal or vertical frequency can be processed, whereas signals whose horizontal or vertical frequency has not been doubled cannot be processed.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide an apparatus for converting the format of a video signal, by which both a video signal having an undoubled horizontal/vertical frequency and an input video signal having a doubled horizontal/vertical frequency can be processed by determining the format of a received external video signal.
Accordingly, to achieve the above objective, there is provided an apparatus for converting decoded video signals and external input video signals R, G, and B, into signals having formats which are required by a signal processor, the apparatus comprising: an analog-to-digital (A/D) converter for converting the external input video signals into digital signals; a space converter for converting the R, G, and B digital signals output from the A/D converter into a luminance signal Y and color-difference signals U and V; a first format converter for converting the composition ratio of the Y, U, and V signals of the space converter into a Y:U:V composition ratio that is the same as the composition ratio of the decoded image signals; a first multiplexer for receiving the decoded video signals and the Y, U, and V signals output from the first format converter, and selecting and outputting one group of input signals according to a first selection control signal; a horizontal/vertical frequency converter for doubling the horizontal or vertical frequency of output signals of the first multiplexer; a second format converter for converting the composition ratio of the output signals of the horizontal/vertical frequency converter into the composition ratio of the luminance signal and the color-difference signals which is suitable for the signal processor; a second multiplexer for receiving the output signals of the second format converter and the output signals of the space converter, and selecting and outputting one group of input signals according to a second selection control signal; and a controller for generating first and second selection control signals depending on the horizontal/vertical frequency of the external input signals R, G, and B and on whether the external input signals are to be output, according to the selection of a user.
REFERENCES:
patent: 5784116 (1998-07-01), Pan et al.
patent: 5905536 (1999-05-01), Morton et al.
patent: 5982432 (1999-11-01), Uenoyama et al.
patent: 5995154 (1999-11-01), Heimburger
Kostak Victor R.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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