| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of causing many cases of out of focus because a just focus point is hardly recognized particularly from an HDTV camera in the case of focus matching of a video camera. SOLUTION: An input terminal 1 receives a luminance signal Y, a high pass filter 21 in a high frequency signal level detection circuit 2 extracts only a high frequency component of the luminance signal Y, an absolute value voltage 22 detects the absolute value of the component, and an integral circuit 23 integrates the entire image or part of the image and provides an output. A latch circuit 3 latches the output for one vertical scanning line (1V) period, a comparison circuit 4 compares an output of the high frequency signal level detection circuit 2 with an output of the latch circuit 3, and a display signal generating circuit 5 outputs the magnitude relation in a way of e.g., an upward arrow, a point indication, and a downward arrow. Whether a focusing direction or an out of focusing direction can easily be recognized depending on whether the amount of the high frequency signal is increasing or decreasing. COPYRIGHT: (C)2004,JPO&NCIPI |
