SUCCESSIVE APPROXIMATION TYPE SHADING DISTORTION CORRECTION CIRCUIT

摘要

PURPOSE:To obtain a high speed and highly integrated shading distortion correction circuit by rewriting a correction signal depending on a difference of a fixed value of a read signal of a reference white level and storing the inverted waveform of distortion in a line memory. CONSTITUTION:An arithmetic circuit 2 receiving an output of a multiplier 1 and a correction signal and multiplying a constant to a difference between a reference white level and a correction signal and giving an output additively to the correction signal, a selector 3 outputting selectively the output of the arithmetic circuit 2 and a correction signal 7 through an external control line, and a line memory 4 in which the output of the selector 3 is written as a new correction signal are provided to the circuit. Thus, no divider is required for the correction calculation and the operation is realized by the multiplier 1, then the constitution by logic circuits is attained and no ROM is required. Thus, high speed operation is facilitated.