| 摘要 |
PURPOSE:To detect the volume of defocus of photographic lens in a short time by calculating the corelation between two figure patterns read by a sensor in time series at a CCD corelation meter and obtaining a phase shift extent from the time giving the maximum value of calculated result. CONSTITUTION:A CCD corelation meter 13 and a peak position detecting circuit 17 are driven by the output signal of a line sensor driving circuit 19 which drives based on the control signal outputted from a CPU18 which is a control circuit. Through the CPU18, short forcus, long focus and just focus is displayed to display circuit 20 by the value of (m) including a sign in case of focus aide, or the defocus extent is drived to output a signal to a photographic lens driving circuit 21 in case of auto-focus, then the photographic lens is driven to the right focal position. In such a focus determination device, the time necessary for the calculation of detection of focus is the charge transfer time inside the CCD corelation meter, therefore, the time is substantially shorter compared with the normal calculating operation. |
