Image signal processing apparatus for y/c separation and for time

Abstract

An image signal processing apparatus is provided which is applicable to a motion adaptive Y/C separation of an NTSC signal and a time-domain/spatial interpolation of a high definition television signal band-compressed by sub-Nyquist sub-sampling. The apparatus includes a still image processing circuit having frame memories, a motion image processing circuit having a line memory, a mixing circuit for mixing outputs of these processing circuits, a circuit for detecting image motion of an input image signal and applying a resultant control signal to the mixing circuit, and a signal mode control circuit for selectively adapting the image processing circuits for the processing of the NTSC signal or the high definition television signal. The motion detecting circuit includes a narrow band detecting circuit for producing a one-frame interval difference signal of a signal spectrum of a pure low frequency component from the NTSC signal or the high definition television signal respectively, a wide band detecting circuit for a two-frame interval difference signal and a composition circuit for composing outputs of these detecting circuits. The still image processing circuit, motion image processing circuit and mixing circuit are adapted to operate for the Y/C separation with the NTSC signal and for the interpolation of the high definition television signal, respectively.