| 摘要 |
PURPOSE: To perform the autofocus control of a television camera with high accuracy and inexpensively. CONSTITUTION: The evaluation value processing circuit in a vertical direction is composed by including a horizontal direction average value calculation filter 1 controlled by a timing generator 2, a digital high-pass filter 3 provided with a flip-flop 4 as a delay circuit, an absolute value processing circuit 5, an integration circuit 6 controlled by a frame control signal 7 and a horizontal synchronizing signal 8 further controlling the digital high-pass filter 3, the absolute value processing circuit 5 and the integration circuit 6. After a luminance signal Y is inputted in a horizontal direction average value calcultion filter 1, the average number of arbitrary number of picture element of a horizontal line is calculated, the signal is synchronized with the horizontal synchronizing signal 8 in the digital high-pass filter 3, a high frequency component is extracted and an absolute value processing is performed, the high frequency components of all the horizontal lines are integrated in the range controlled by the frame control signal 7 and the evaluation value for autofocus is calculated. |
