| 摘要 |
PURPOSE:To obtain a picture whose contrast is easily diagnosed by correcting a non-linear characteristic through a gamma correction circuit and reducing an influence such as an irregular illumination through a latitude correction circuit with respect to a luminance signal of a posterior step. CONSTITUTION:A picture signal of an optical image photoelectrically transferred by a solid-state image pickup element 4 is amplified by a preamplifier 14 of low noise exponent and inputted to an AGC circuit 15 and inputted to an integrator 16 in order to form a signal for a dimmer. The gamma correction circuit 21 is a circuit for correcting the photoelectric transfer characteristic of the solid-state image pickup element 4, the non-linear characteristic of a display tube (display device), the non-linear characteristic of a system or the like. After the correction is performed, the signal is inputted to an A/D converter 22 and converted to a digital quantity. The latitude correction circuit 28 compresses the inputted luminance signal to suitably set within an easily diagnosed brightness level range which is no too dark and too bright.
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