Video signal processing circuit

• US 6,243,083 B1
• Filed: 07/21/1998
• Issued: 06/05/2001
• Est. Priority Date: 07/23/1997
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Inoue, Toshiaki, Mitarai, Shozo, Arimizu, Akira
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Osorio, Ricardo
• Application Number:
  US09/119,623
• Time in Patent Office: 1,050 Days
• Field of Search: 345/154, 345/204, 345/429, 348/659, 348/661
• US Class Current: 345/204
• CPC Class Codes: H04N 5/208 for compensating for attenuation of high frequency components, e.g. crispening, aperture distortion correction
• CPC Class Codes: H04N 9/646 for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters

Abstract

To obtain a clear-cut picture image by correcting a contour of a video signal of a natural picture image and the like from a computer.

Video signals of, for example, three primary colors (R, G, B), including a natural picture image and the like produced by, for example, a computer from input terminals 1 are supplied to a mixing circuit (2) and mixed at a ratio of, for example, 0.6G+0.3R+0.1B to produce a signal corresponding to a luminance (Y). This signal is supplied to differentiation circuits 3A and 3B having different time constants each other and predetermined high frequency components are extracted therefrom, respectively, and these output signals are selected by a switch (4), and then supplied to an amplifying circuit 5. The gain of the amplifying circuit 5 is arbitrarily controlled by a signal from a control terminal (6). Then, a signal from the amplifying circuit (5) is supplied to adding circuits 7R, 7G and 7B and added therein to respective video signals of R, G and B to then be derived from output terminals 8R, 8G and 8B.

Claims

1. A video signal processing circuit, comprising:

means for inputting or producing a plurality of primary color signals;

means for mixing said plurality of said inputted primary color signals at a predetermined ratio to produce a signal corresponding to a luminance; and

means for extracting a high frequency component of said signal corresponding to the luminance and adding the high frequency component to each of said plurality of primary color signals.

2. A video signal processing circuit as claimed in claim 1, wherein said plurality of primary color signals are produced by a computer and wherein processed video signals are displayed on a display.

3. A video signal processing circuit according to claim 1, comprising:

a mixing circuit for mixing said plurality of inputted or produced primary color signals at a predetermined ratio;

a differentiation circuit for extracting a high frequency component of the signal corresponding to said luminance;

an amplifying circuit for amplifying a signal from said differentiation circuit; and

an adding circuit for adding a signal from the amplifying circuit to each of said to plurality of primary color signals.

4. A video signal processing circuit as claimed in claim 3, wherein said circuit further comprises a second differentiation circuit, wherein said differentiation circuit and second differentiation circuit have different time constants, and wherein said circuit further comprises means for controlling a gain of said amplifying circuit.