JPS6470887A - Binarized threshold setting system - Google Patents

Abstract

PURPOSE:To automatically set up an optimum binarized threshold by a simple algorithm at the time of changing a condition of an optical system by providing the titled system with a histogram processing means, a statistical processing means, a density threshold acquiring processing means, and so on. CONSTITUTION:A luminance threshold setting circuit 3 consisting of a histogram circuit 4, a noise removing circuit 5, a statistical processing circuit 6, and a luminance threshold calculating circuit 7 sets up and outputs a luminance threshold Lth. By means of a prescribed formula based on input multi-gradation pattern image data PDn. The value Lth is supplied to a multivalued image processing part 11 and a multivaluing circuit 12 and the data PDn previously stored in a multivalued image memory 10 are successively supplied to the circuits 11, 12 when it is necessary. The data PDn are binarized by the circuit 12 in accordance with the value Lth, and the binary value is stored in a binary image memory 13 constituted of a RAM or the like, and if necessary, read out by a binary image processing part 1. Thus, an optimum binarized threshold can be automatically set up by the simple algorithm at the time of changing the condition of the optical system.