| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a signal processing circuit for accurately correcting a nonlinear characteristic at low illuminance. <P>SOLUTION: A luminance level detection circuit 1-17 detects the average value of luminance on the basis of an output signal from a composite circuit 1-6. A microcomputer 1-18 discriminates whether the illuminance is a regular illuminance or a low illuminance on the basis of an output from the luminance level detection circuit 1-17 and gives a control signal to a correction control circuit (1) 1-13 and a multiplier 1-19. An image signal output 1-9 is fed back to an AGC control circuit 1-8 which calculates an AGC control coefficient for a multiplier 1-7 so that the average luminance is constant. The multiplier 1-7 multiples the AGC control coefficient with the output of the multiplier 1-19 and provides the output of the image signal 1-9. A video signal is produced from the image signal 1-9. A detection circuit 1-10 detects a nonlinear distortion characteristic of image data of left and right image regions and gives detection data of the nonlinear distortion characteristic with respect to respective image data of the left/right image regions to a correction control circuit (2) 1-14 and a correction control circuit (3) 1-15. A selection circuit 1-16 selects either correction data outputted from the correction control circuit (2) 1-14 or the correction control circuit (3) 1-15 and gives the selected correction data to a nonlinear correction circuit 1-5. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
