PURPOSE: To set an optimum binary-coded threshold level, and to obtain a good reproducing picture, by deciding a classification of the picture by the first density signal which executes image pickup of an area to be discriminated, by a unit read spot of a prescribed area or more, and deriving a picture density range by the second density signal which executes image pickup by a spot of the prescribed area or less.
CONSTITUTION: The first density signal Se1 which executes image pickup of an area to be discriminated, by a unit read spot of a prescribed area or more, and the second density signal Se2 which executes image pickup of its area by a unit read spot of the prescribed area or less are detected and outputted by a density detecting circuit 36. These respective signals Se1, Se2 are sampled by sampling circuits 371, 372, and A/D- converted by A/D converters 373, 374, and its picture density signals Sd1, Sd2 are read to a CPU375. Also, a histogram relative to the signals Se1, Se2 is generated in an RAM376. Subsequently, a threshold level group having a prescribed density distribution is set in accordance with the signal Sd1, and a new threshold level group is calculated from said threshold level group by an operating part 380 in accordance with the signal Sd2, and the binary-coding is executed by a comparator 383 by using its calculated threshold level group.
| JPH07266614 | IMAGE RECORDING APPARATUS |
| JPS6299777 | COPYING DEVICE |
| JPH0486885 | IMAGE FORMATION DEVICE |
ABE YOSHINORI
SHIYOUJI HISAFUMI
