A high-density ternary barcode detection system with a fixed-period delay method

Abstract

A fixed-period delay method is proposed to increase the detection range and detection stability of a ternary barcode detection system. The system combines an envelope differential detection technique containing nonlinear filtering and a fixed-period delay to detect the barcode over a longer range and at higher scanning speeds while being simple and capable of handling a large amount of information. The system was demonstrated with its miniaturized circuit and it was established that the detection range of the system for a minimum bar width W=0.25mm was 1.8 times that of the conventional count-latch envelope differential technique because of the stable delay achieved by a shift register and the noise suppression by a nonlinear filter. In addition, the system operated at a maximum scanning speed of 8.3 times that of conventional charge-coupled device (CCD) cameras under the practical detection range for W=0.3mm. This system is expected to enable the real-time identification of goods on production lines and in automated warehouses.