NOISE REDUCING APPARATUS

摘要

A noise reducing apparatus capable of controlling afterimages through Hadamard transform of the difference signal between two conscutive fields, wherein block distorsion is decreased by assuming a factor obtained for reverse Hadamard transform as only one data value for each conversion area. Specifically, the field difference signal (Ob) obtained by subtracting the output of a field memory (2) from the input image signal through a first subtracter (1) is input to a 1H delay element (3) and a Hadmard transform circuit (4). The circuit (4) determines an area for Hadamard transform by the field difference signal (Ob) from the first subtracter (1) and a signal (Oa) that is the 1H delayed (Ob) from the delay element (3). The area for Hadamard transform is shifted pixel by pixel for execution of sequential conversion. It is possible to greatly reduce the circuit size and control afterimages produced when an edge with a high contrast moves by properly determining the position of one data value obtained through reverse transfrom in the transform area. <IMAGE>