| 摘要 |
<p>PURPOSE:To prevent erroneous discrimination of motion detection by comparing picture element signals having one field period between them to detect the difference signal and comparing picture element signals having one frame period between them to detect the sum signal and checking amplitude relations between sample points in the preceding field and the preceding frame. CONSTITUTION:Output signals of threshold circuits 116 and 120 are inputted to an OR circuit 121. The output of this circuit 121 is inputted to an AND circuit 123 together with the outputs of threshold circuits 110 and 112. If an input signal consists of only color signals for a still picture, the output of the threshold circuit 110 is '1' because of the same picture, and the output signal of the threshold circuit 112 is '1' because color signals have opposite phases. One of outputs of threshold circuits 116 and 120 is '1', and the output of the OR circuit 121 goes to '1'. Consequently, all inputs of the AND circuit 123 are '1', and the output is '1', and the output of an OR circuit 124 is '1', thus indicating the still picture.</p> |
