PICTURE READER

申请公布号：

JPS61224564(A)

申请号：

JP19850064796

申请日期：

1985.03.28

申请公布日期：

1986.10.06

申请人：

KONISHIROKU PHOTO IND CO LTD

发明人：

FUNAKI SHINSUKE

分类号：

H04N1/04;H04N1/19;H04N5/335;H04N5/361;H04N5/369;H04N5/372;H04N5/378

主分类号：

H04N1/04

摘要：

PURPOSE:To fix stably a black level signal over the entire page of the original by applying arithmetic a voltage of a prescribed value at an arithmetic circuit to an output signal of a solid-state image pickup element when it is discriminated that the output of the element at dark state is not within a set value. CONSTITUTION:A digital comparator 12 brings the level of output terminals 12a, 12b to H when a picture signal A and a comparison signal B are in the relation of A>B and A=B, and brings the level of an output terminal 12c to an H level when A<B, and brings it to an L in other cases. An AND gate 14 receives a count pulse in the cases other than A=B. When a dummy picture element of a CCD 1 is scanned A>B is established, and when a count pulse comes, the counter 16 counts up by a count pulse from an AND gate 13, the quantity of subtraction to a picture signal from the CCD 1 is increased at a substractor 10 and the signal A is decreased. When A<B, the signal A is increased. The operation above is repeated at each incoming of the signal A and it continues until A=B is established. So long as a decreasing voltage is given to the substractor 10 on the condition of A=B, the black level is fixed.