EVALUATING DEVICE OF SHADING DISTORTION CORRECTING CIRCUIT

摘要

PURPOSE:To evaluate precisely the correcting performance of a shading distortion correcting circuit itself by calculating a difference signal between shading distortion correcting result signals outputted from the shading distortion correcting circuit and a correcting result operating circuit. CONSTITUTION:A digital subtractor 20 of evaluation device 11 subtracts the shading distortion correcting result signal outputted from the shading distortion correcting circuit 22 and the shading distortion correcting signal outputted from the correction result operating circuit 16 and outputs a difference signal of both the signals. After the difference signal is converted into an analog signal by a D/A converter 21, the signal is inputted to an oscilloscope 13 and deformation of the difference signal is displayed on the oscilloscope 13. The correcting error of the circuit 12 itself is measured precisely by observing the displayed waveform on the oscilloscope 13 and the correcting capability of the circuit 12 itself is evaluated quantitatively and accurately.