| 摘要 |
PURPOSE:To realize stable binary coding which is not affected by the level variations of illumination, the shading characteristics of an image pickup device, etc., by switching binary-coded signals when the change of signal level exceeds a fixed level. CONSTITUTION:The binary coding is carried out with a fixed threshold value T until the 1st binary coding switch point A, and the floating threshold value T' is used at and after the point A. When the binary coding level is 1, the value T' is decided to a level that is lower than the maximum value P1 by the prescribed set value V1 until the next switch point B. This value T' is not fixed and rises up with the rise of an input video signal g(t). Then the point B is used as the binary coding switch point in case the signal level drops. In such a way, the value T' is defined as the threshold value and then switched as a binary coding level. Thus a binary-coded signal that is approximate to an ideal form can be obtained as shown by the diagram. |
