Television – Format conversion
Reexamination Certificate
1999-01-07
2001-12-25
Lee, Michael (Department: 2714)
Television
Format conversion
C348S445000, C348S446000, C348S714000, C345S601000, C345S602000, C345S603000, C382S300000
Reexamination Certificate
active
06333762
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a scan format converter for converting a video format, and in particular, to a method for making look-up tables of variables and interpolation values necessary for bi-sigmoid interpolation and a scan format converter for converting an input video format to another video format by using the look-up tables.
2. Description of the Related Art
With the popularization of personal computers (PCs), there are demands for a personal computer capable of displaying a video output thereof through a display unit of a home television or a projection television. In practice, however, since there is a discrepancy in the number of the scanning lines between the television set and the personal computer, it is impossible to output various formats (e.g., SVGA, XGA, VGA, etc) input from the personal computer to the display unit, as they are. Accordingly, it is necessary to convert the input video formats in conformity with the properties of the display unit. A scan format converter has been developed for that purpose.
However, the conventional scan format converter, utilizing bi-linear interpolation or zero-order interpolation, cannot display the high quality image of the personal computer to the display unit of the television set or the projection television.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a method for making look-up tables of variables and interpolation values necessary for bi-sigmoid interpolation, and a scan format converter for converting a video format by using the look-up tables.
It is another object of the present invention to provide a method for making look-up tables with which it is possible to convert a video format using bi-sigmoid interpolation, and a scan format converter for converting the video format by using the look-up tables.
It is still another object of the present invention to provide a scan format converter for a video signal processing device, which can provide fast video format conversion by using bi-sigmoid interpolation.
According to one aspect of the present invention, a method for making look-up tables for video format conversion in a video signal processing device includes the steps of calculating first and second displacement values representing that pixel points of a first video format are spaced apart from corresponding pixel points of a second video format with respect to an x-axis and a y-axis, respectively, the first video format having a different resolution from that of the second video format; tabling the calculated displacement values with respect to the respective pixel points of the second video format; and sigmoid-interpolating displacement values, in the x-axis and the y-axis, for the same pixel points between the first and second video formats and level difference values between two contiguous pixel points in the first video format, and tabling the sigmoid-interpolated level values in association with the displacement values.
According to another aspect of the present invention, a scan format converter for converting a video format by bi-sigmoid interpolation includes a memory controller having a look-up table at which first and second displacement values for pixel points of a video format to be converted are stored, for controlling transmission of color signals input from an external device, and reading the first and second displacement values for the pixel points of the color signals from the look-up table; a mode detector for detecting horizontal and vertical sync signals input from the external device and outputting a video format detection signal representing a mode of the currently input video format to the memory controller; a memory for temporarily storing the color signals; a color signal logic circuit having a plurality of bi-sigmoid interpolation tables at which sigmoid interpolation values according to a color signal level difference between two pixel points are stored, for bi-sigmoid-interpolating the color signal levels of the input pixel points with respect to an x-axis and a y-axis according to the first and second displacement values input from the memory controller; and a sync generator for generating a sync signal to the color signal logic circuit.
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Choi Jong-Chul
Hong Chang-wan
Jeong Yeon-Mo
Lee Jae-Jun
Yoo Joong-Sun
Desir Jean W.
Lee Michael
Samsung Electronics Co,. Ltd.
Sughrue & Mion, PLLC
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