Television – Image signal processing circuitry specific to television – Transition or edge sharpeners
Reexamination Certificate
1998-12-09
2001-02-06
Hsia, Sherrie (Department: 2714)
Television
Image signal processing circuitry specific to television
Transition or edge sharpeners
C348S537000, C348S665000
Reexamination Certificate
active
06184939
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to apparatus for processing video signals and and more particularly to an apparatus which employs phase-locked loop and analog to digital conversion to obtain high quality static image.
BACKGROUND OF THE INVENTION
Video signals processed by a conventional apparatus, when redisplay on a monitor connected to a computer system, suffer several problems, such as false color at the edge of an image. Additionally, too high hardware cost inevitably lower the competitiveness of the apparatus. Another drawback of a conventional video signal processing apparatus lies in its comb filter. Conventional comb filters process video signals which are sampled on two adjacent horizontal scanning lines, without considering the resolution of vertical direction. The resolution of processed images is thus scarified.
H. Hagino, etc. in U.S. Pat. No. 5,523,798 describe a circuit for adjusting signal separation in Y/C separation comb filter by hardware connecting a phase-locked loop to a burst gate pulse generation circuit and multipliers. This greatly increases hardware costs. In addition, in separating a luminance signal and a chrominance signal, the comb filter of U.S. Pat. No. 5,523,798 takes only two dimensions into consideration. As a result of such two dimensional processing, the image processed suffers from false color and low resolution. Stuart S. Perlnan in U.S. Pat. No. 4,961,108 describes a circuit for comb filtering PAL and NTSC video signals. The comb filter of U.S. Pat. No. 4,961,108 also takes only two dimensions into consideration in processing video signals. Therefore, the problems of false color and low resolution can not be avoided.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an apparatus for processing video signals by means of employing phase-locked loop in combination of the technology of analog to digital conversion.
It is another object of the invention to provide an apparatus for processing video signals which can effectively increase the quality of captured static images without increasing costs.
It is yet another object of the present invention to provide an apparatus for processing video signals which can effectively lower hardware costs and increase competitiveness of the product.
It is still another object of the present invention to provide an apparatus for processing video signals and apparatus thereof, which double samples the captured static images and therefore increases the overall resolution of the captured images.
REFERENCES:
patent: 4415918 (1983-11-01), Lewis, Jr.
patent: 4506291 (1985-03-01), Lewis, Jr.
patent: 5175619 (1992-12-01), Willis
patent: 5870153 (1999-02-01), Murray
patent: 6-261224 (1994-09-01), None
Cheng Wen-Chin
Lin Shih-Hsun
Wang Shin-Su
Dougherty & Troxell
Hsia Sherrie
Umax Data Systems Inc.
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