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Electronically operating automatic focussing system - uses multielement photosensitive sensor which scans optical field and results of successive scans are compared
Electronically operating automatic focussing system - uses multielement photosensitive sensor which scans optical field and results of successive scans are compared
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机译:电子操作自动聚焦系统-使用多元素光敏传感器,可扫描光场并比较连续扫描的结果
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摘要
An automatic focussing device for cameras or projectors based on the use of electronics and light-sensitive elements. A sensor containing a number of light sensitive elements generates signals according to the intensity of light received, and it can be controlled in its distance from a point in the optical system by a control sginal. A circuit derives a mean signal value from all the individual sensor elements, whilst a second circuit determines the difference between each individual signal and this mean value. A third circuit forms the sum of all the positive or negative difference generated in the second circuit over a scanning cycle covering all the individual elements. The output signal from the third circuit over one cycle is compared in a fourth circuit for successive scanning cycles and according as the result is greater or smaller, generates a control signal to shift the focus in one sense or the other.
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