Picture processing apparatus

Abstract

An image processing apparatus useful in, for example, FAX machines, for processing a binary or multiple level tone data in an image including a switch for selectively outputting either a binary level or the multiple level tone pattern in accordance with a selection signal the state of which is determined by the interline reading interval times while scanning the image on an original document. The image processing apparatus includes a temporary storage register for storing a digital binary or multiple level tone pattern, and a selection switch controlled by a binary/multiple level tone selection signal for selectively coupling to the maximum voltage reference input of an analog-digital converter an output signal either from a background color compensator when the binary/multiple level tone selection signal indicates binary level tone image processing is occurring or a voltage value established by a first voltage divider whose resistor values are predetermined according to output voltage levels from the image sensor during multiple level tone image scanning. The digital-analog converter converts binary or multi-level tone pattern data output from temporary storage register into an analog signal using a minimum voltage reference established by a second voltage divider which has resistor values selected in accordance with the minimum output levels from the image sensor. The analog signal from the digital-analog converter is converted to a voltage and compared in a comparison calculator to generate digital data representing the scanned image.