METHOD AND DEVICE FOR DISCRIMINATING PICTURE QUALITY OF PICTURE READER

PURPOSE:To make high-speed input possible by discriminating whether the read results of two optical systems are a prescribed value or in a prescribed range corresponding to the density of every reference mark or not and judging that binarization densities on front and rear faces of a double sided original coincide with each other if said read results are the prescribed value or in the prescribed range. CONSTITUTION:Since reference rollers 23 and 24 are rotated before an original 13 is carried to an optical system part, optical system on the front side and the rear side read reference marks 35a-35c. Information of read reference marks 35a-35c is inputted to a binarization circuit 2 through a preamplifying circuit 1 and is converted to black-and-white binarization information by a threshold outputted from a threshold switching circuit 9. The number of black dots of this binarization information is counted at every reference marks 35a-35c by a counter 5 and is outputted to a comparing circuit 6. The comparing circuit 6 performs the comparing operation at every reference marks 35a-35c and outputs the result to a control processor 8. The similar operation is executed in the optical system and the electric system on the rear side, and the comparison result at every reference marks 35a-35c provided on the reference roll 24 is outputted to the control processor 8.