| 摘要 |
PURPOSE:To prevent the generation of a false signal due to folded distortion, by providing an optical filter in which a space frequency of an objective image is an integral times of the Nyquist frequency determined with the picture element interval of an image pickup device, between the device and the objective. CONSTITUTION:An objective 1 is formed on a photoelectric plane of a solid-state image pickup device 4 with a lens 2. An optical filter 3 provided with a double refraction characteristic is inserted between the lens 2 and a solid-state image pickup device 4, and the spatial sampling interval of horizontal picture elements of the device 4 and the separation width of abnormal rays of the optical filter 3 to a normal ray can be coincident. The aperture ratio of the device 4 to the horizontal direction is taken as 1.0 and the optical filter 3 and the device 4 are selected so that the modulation of the picture signal is zero at a multiple of the Nyquist frequency, allowing to prevent the deterioration in the picture quality due to a false signal. |
