| 摘要 |
<p>PURPOSE:To accurately decide a dynamic level even when a noise, etc., exist in a picture signal by obtaining the difference in the picture signal with a frame memory and a subtracter, making the absolute value of the difference into dynamic quantity, and making either the center value or the average value of the absolute value into a dynamic level deciding signal. CONSTITUTION:The picture signal is delayed for one frame by a frame memory 2, and the difference between the picture signal at a current point and that delayed for one frame is obtained by a subtracter 3. Further, the absolute value of difference amplitude is obtained by an absolute value circuit 4 and made into the dynamic quantity of a picture. The output of the absolute value circuit 4 is successively outputted to a delay memory group composed of delay memories 61, 51, 52 and 62, and the outputs of the respective delay memories are inputted to an center value circuit 7. The center value circuit 7 obtains the center values of respective input signals and makes the center values into the dynamic quantity of the picture for a signal d0 at the current point as a center picture element. Consequently, the possibility of receiving the influence of a spike shaped noise, etc., becomes small, and the dynamic level decision which hardly receives the influence of the noise, etc., can be attained.</p> |
