CORRELATOR AND PICTURE CORRELATOR, SIGNAL ADDER, PICTURE PROCESSING CIRCUIT AND AUTOMATIC FOCUSING CAMERA USING THEM

摘要

PROBLEM TO BE SOLVED: To reduce a circuit scale and to realize a highly accurate correlation calculation by comparing calculated results obtained according to combinations of cell signals with a reference signal. ;SOLUTION: A multiplexer (MPX) selector 4 as a changing means (selection switch) outputs the picture signal of one side while shifting elements one element (one cell) at a time or two elements (two cell) at a time in the horizontal direction and outputs the picture signal of the specific part of a frame by shifting a signal one frame at a time in the case of obtaining the correlation of the vertical direction. A peak detecting circuit 5 outputs a peak signal for every outputting of the objective pixel of the MPX selector 4. Then, an adjacent difference detecting circuit 9 detects the difference between peak outputs of adjacent pixels among peak outputs for every objective pixel of the peak detecting circuit 5. Moreover, an adding circuit 6 as an arithmetic and logic circuit adds the outputs of the adjacent difference detecting circuit 9 and outputs results. Further, an amplifier 7 performs the level shifting of the added outputs of the adding circuit 6 and a zero-cross detecting circuit 8 detects the maximum correlation point.;COPYRIGHT: (C)1997,JPO