| 摘要 |
PROBLEM TO BE SOLVED: To emphasize a contour of spatial frequency components of which frequencies are higher than a frequency (1/4) fsv that is 1/4 of a vertical sampling frequency fsv being a pixel rate of a CCD. SOLUTION: A delay circuit 20 of the image pickup unit receives a full line image pickup signal read from a CCD image sensor and gives signals [H1D]-[H4D] by four consecutive lines to a 2nd vertical contour emphasis circuit 50 of a Y process circuit 40 via a pre-processing circuit 30. A subtractor 51 of the 2nd vertical contour emphasis circuit 50 sums/subtracts the signals [H1D]-[H4D] outputted from each of delay elements 21-24 to obtain a signal -[H1D]+[H2D]+[H3D]-[H4D] as an output from the subtractor 51. This output is extracted through a horizontal low pas filter 52 and an amplifier 53. The contour can be emphasized around the spatial frequency components higher than the frequency (1/4) fsv through the arithmetic operation of the four lines of the signals in the vertical direction.
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