| 摘要 |
PURPOSE:To prevent erroneous decision by spurious resolution by disposing photodetector arrays on the focal plane of an image-forming lens and before and behind the same or in the positions conjugate with the same, applying reference potentials for compensation to the signals for sharpness of images and processing the signals. CONSTITUTION:A film F is disposed on the focal plane of an image-forming lens L, and a photodetector array MA is disposed in the position conjugate with the position thereof. Photodetector arrays FA, BA are disposed in the positions before and behind said position. Sfa, Sma, Sba denote signal processing circuits, which are connected to the arrays FA, MA, BA. These circuits receive the signals converted photoelectrically from the projected light images, operate the same arithmetically according to evaluation functions, and outputs the evaluation values thereof as analog electrical signals to terminals Tf, Tm, Tb. The evaluation values attain the max. values when the image-forming point of the lens L is just on a certain photodetector array and decrease as the imaging point deviates. When the imaging point deviates considerably, again the small peak of the evaluation values is made by the spurious resolution. |
