| 摘要 |
PURPOSE:To obtain an inexpensive, high-performance device by converting pieces of luminous flux from positions at specific distance into time-series image signals and storing them, and amplifying a signal of a picture element which is a specific number of elements away differentially and comparing the amplified signal to a reference level. CONSTITUTION:Pieces A and B of luminous flux positions which are a specific distance apart are passed through a focal system lens 1 and luminous flux which is split by a light splitting system 2 and travels straight is passed through an image forming lens 3 to form an image on an image pickup surface 4. Luminous flux bent by the light splitting system 2 is passed through image forming lenses 5 and 6 to form a subject image on an image sensor (CCD)7, and the image shifts in position unless correct focusing is obtained on the image pickup surface 4. A CCD driving circuit 8 obtains a time series signal as to the positions of two images on the CCD7 and then codes it into a binary signal 9, which is processed by a correlator 10 to input the degree of matching to an arithmetic circuit 11; and the difference between a maximum and a reference value is calculated and used as the amount of defocusing for drive 12, controlling a lens system 1. Consequently, focusing is attained easily and accurately. |
