Patent ID: 7339702

Claim:
A picture reading device for discriminating a type of a recording medium, comprising: an irradiating element that irradiates a surface of the recording medium; and a picture reading part for receiving reflection light from the recording medium, wherein said picture reading part is constructed as a monolithic semiconductor chip and includes: a reading element for reading a picture of a surface of a reading target and photoelectrically converting the picture; an A/D conversion circuit for convening information of the picture read by said reading element into a digital value; a calculation circuit for calculating a parameter concerning a smoothness characteristic for discriminating the type of the recording medium based on two-dimensional picture information having a plurality of digital values converted by the A/D conversion unit; and an output part for outputting a result of the calculation by said calculation circuit, wherein said reading element, said A/D conversion circuit, said calculation circuit and said output part are mounted in one chip, wherein said calculation circuit calculates a maximum value, a minimum value and an average value of digital values per a line in a predetermined direction of the two-dimensional picture information, and said output part outputs the maximum value, the minimum value and the average value per line in the predetermined direction of the two-dimensional picture information.