| 摘要 |
PURPOSE:To read an image having intermediate tone such as a photograph by providing a random number generating circuit and a D/A converter to change a reference value binary-coding a signal read by a sensor into two colors (white/ black) at random. CONSTITUTION:A signal read by an image sensor IS is inputted to a noninverting terminal of a comparator 14 and a reference voltage Vcc or an output from a reader 13 is inputted to an inverting terminal via a switch 9. In this case, an output from a terminal 10 is inputted to the comparator 14 normally and when a signal is given from a comparator circuit 8 to the switch 9, the output of the amplifier 13 is inputted in place of the Vcc as the reference voltage for binary-coding. That is, when the scanning of the sensor IS enters an area representing an intermediate tone, a signal is inputted from the circuit 8 to the switch 9 and a voltage signal in response to a random value generated by a random number generating circuit 11 is inputted to the comparator 14 via a D/A converter 12 and the amplifier 13. Thus, the picture having intermediate tone such as a photograph is read. |
