Image identifying apparatus using an image sensor to extract false image data from a document image and discriminate the image by comparing the false image data to a predetermined pattern

摘要

The image sensor according to the present invention comprises a light emitting diode which irradiates light onto a document image, a phototransistor which receives the reflected light and executes photoelectric conversion, an amplifier which amplifies an analog signal from the phototransistor, a time constant circuit into which an analog signal from the amplifier is inputted and which delays the analog signal by a specified period of time, an amplifier into which the analog signal outputted from the amplifier and the analog signal delayed in the time constant circuit are inputted and which differentially amplifies the analog signals, and a knot gate into which the analog signals outputted from the amplifier are inputted and which outputs a digital signal of "0" or "1" according to whether a value for the analog signal is positive or negative.