JPS57202192A - Color picture signal processing circuit - Google Patents

Abstract

PURPOSE:To eliminate the sense of incompatibility through the print of white background for black background, by providing each circuit of detectiong of background color, designated color and edge of a color TV screen and switching an output of an edge detection circuit with the output of the designated color detection circuit. CONSTITUTION:A color TV input of RGB is sequentially switched and converted into Y, M, C at a color signal converting circuit 10. On the other hand, the white or black of the background is discriminated for the RGB input at a background color detection circuit, and an output of an OR gate 20a is reduced to L at black background. Simultaneously, a designated color detection circuit 30 outputs H from an AND gate 30a when the background is white. An edge detection circuit 40 detects the boundary, between the white and black backgrounds and converts the white boundary into black. Through the constitution like this, when the background is black and white characters are given, and when the background is black and white graphs are given, the print of screen is made so as to obtain the black characters on the white background, and black edged graphs on the white background respectively. Thus, the TV screen print without the feeling of incompatibility can be obtained.