BAR CODE READING SYSTEM

摘要

PURPOSE:To read a bar code accurately without reference to the variance of a readout part by equalizing all intervals of black bars by finding and comparing the width of a space area with predetermined one, and varying a slice level on the basis of the comparison result. CONSTITUTION:Read information from a readout part is stored in a register Reg1 and inputted through a multiplexer MPX to a slicing circuit SL to be sliced at a prescribed level by the output of a slice level generating circuit REF. The sliced level infromation from this circuit SL is latched in a latch circuit LCH; and both end positions of a space area adjoining to black bars are stored in registers Reg2-Regn on the basis of the result of the slicing operation and their outputs are compared by a comparing circuit COM1. According to the comparison results of the circuit COM1, the multiplexer MPX and circuit REF vary the slice level to equalize the intervals of the black bars, thereby reading bar codes accurately.