| 摘要 |
PURPOSE:To obtain a copy having good quality, which is free from black frame, by specifying a threshold value for discriminating a frame and an image in an image having a frame. CONSTITUTION:When the maximum output value the minimum output value of photodetecters, and a constant are denoted as Smax, Smin, and (k), respectively, a threshold value Sh is determined as Sh=k(Smax-Smin), and based on this threshold value, a black frame is erased. It is also allowed that the maximum value (Smax) is not taken from the whole image but calculated from a part of the image or data of the peripheral part. That is to say, Smin and Smax can be calculated from different areas. In this way, even in case of an information recording medium of any density, and also, even in case of an information recording medium having no contrast, there is no possibility that an image area lacks, a frame erasion is executed, and a copy having good quality can be obtained. |
