Hitachi, Ltd.

Kohji Minabe

Hideo Nishijima

Hitoaki Owashi

Michio Masuda

Hiroyasu Ohtsubo

Masataka Sekiya

Morito Rokuda

This invention relates to a method and apparatus for processing a color video signal. The processing method separates an input composite color video signal into a luminance signal and chrominance signal, demodulates the separated chrominance signal into color difference signals, stores the separated luminance signal and color difference signals in a memory, reads out the luminance signal and color differnece signals in units of 1-field period from the memory, implements the extension or reduction of the field period length alternately for every certain number of fields in reading out the luminance signal and color difference signals from the memory thereby to fix the phase relation between a residual chrominance signal component in the luminance signal read out of the memory and a chrominance signal produced by modulating the color subcarrier with the color difference signals read out of the memory, implements an intended signal processing for the readout signals, modulates the color subcarrier with processed color difference signals to produce a chrominance signal, and mixes the chrominance signal with processed luminance signal to produce a composite color video signal.

Method and apparatus for processing a color video signal

A digital noise reducer includes an addition circuit for adding a digital input video signal supplied at one input thereof and a signal supplied at the other input thereof and for outputting a resultant sum signal, a delay circuit for delaying the output signal of the addition circuit by an input unit period of the digital input video signal, a subtraction circuit supplied with the digital input video signal and an output signal of the delay circuit, the subtraction circuit forming and outputting a difference component signal for the digital input video signal and the output signal of the delay circuit, and a characteristic adjustment circuit for manipulating a signal characteristic of the difference component output of the subtraction circuit in accordance with the characteristic of the difference component signal outputted from the subtraction circuit and/or a characteristic of a digital output video signal outputted from the addition circuit and for outputting a resultant manipulated signal to the other input of the addition circuit.

Digital noise reducer

Growing community of inventors

Katsuta, Japan

Kohji Minabe