ABSTRACT A dual-bias differential
method is presented for increasing the detection range of a ternary barcode detection
system. The system is provided with a second differential delay circuit with
bias control to process optimally gray signals by lowering their averaged level
using a clamping circuit. This is added to the primary conventional
differential delay circuit without bias control and a comparator to process
optimally black signals based on the envelope-differential fixed-period delay
(EDFPD) detection technique. This method enables the system to detect over a
longer range at high speeds while being capable of handling a large amount of
information. The estimate results of gray and white code widths against the
clamp bias made through the dynamic operation simulation of a differential
circuit using SPICE were nearly consistent with the experimental results.
Thereby we can conclude that the dynamic simulation is effective for estimation of an optimum clamp bias
voltage. It was confirmed that the detection range of the system with a clamp
bias voltage of ?0.4
V for a minimum bar width W = 0.25 mm was 1.4 times that of the conventional
EDFPD detection technique. In addition, the system operated at a maximum
scanning speed of 7.7 times that of conventional CCD cameras under the
practical detection range. The system with clamp bias control is expected to
enable the real-time identification of goods on production lines and in automated
Cite this paper
H. Wakaumi, "A High-Density Ternary Barcode Detection System with a Dual-Bias Differential Method," Journal of Sensor Technology, Vol. 3 No. 1, 2013, pp. 6-12. doi: 10.4236/jst.2013.31002.
 T. Kan, N. Ri, O. Shin and T. Tei, “Machine Recognizable Code and Its Encoding Decoding Method,” Japan Patent No. 3336311, August 2002.
 H. Endo and M. Takahashi, “Two-Dimensional Code and Two-Dimensional Code Reader and Program,” Japan Patent No. 4435851, January 2010.
 A. P. Gross and D. X. Rodriguez, “Color and Shape System for Encoding and Decoding Data,” US Patent No. 5869828, February 1999.
 J. Hiramoto, “Knowledge of Barcode and Two-Dimensional Code,” 5th Edition, Japan Industrial Publishing, Tokyo, 2001.
 T. Nagaya, T. Yamazaki, M. Hara and T. Nojiri, “TwoDimensional Code for High-Speed Reading,” Proceedings of the 52th Information Processing Society of Japan (IPSJ) General Conference, 6-8 March 1996, pp. 253-254.
 H. Wakaumi and C. Nagasawa, “A Ternary Barcode Detection System with a Pattern-Adaptable Dual Threshold,” Sensors and Actuators A: Physical, Vol. 130-131, 2006, pp. 176-183. doi:10.1016/j.sna.2005.12.017
 H. Wakaumi and C. Nagasawa, “A 2D Ternary Barcode Detection System with a Dual Threshold,” Proceedings of the 5th IEEE Conference on Sensors, Daegu, 22-25 October 2006, pp. 1511-1514.
 H. Wakaumi, “A Six-Line Ternary Barcode Detection System with a Dual Threshold Method,” International Journal of Mechatronics and Manufacturing Systems, Vol. 3, No. 3-4, 2010, pp. 261-273.
 H. Wakaumi, “A High-Density Ternary Barcode Detection System Employing an Envelope-Differential Composite Method,” Proceedings of the 7th IEEE Conference on Sensors, Lecce, 26-29 October 2008, pp. 1076-1079.
 H. Wakaumi, “An Envelope-Differential Composite Method for a High-Density Ternary Barcode Detection System,” The IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. J94-A, No. 2, 2011, pp. 142-144.
 H. Wakaumi, “A High-Density Ternary Barcode Detection System Employing a Stable Fixed-Period Delay Method,” Optical Review, Vol. 18, No. 5, 2011, pp. 408-413.
 H. Wakaumi, “A Ternary Barcode Detectionn System Employing a Dual-Bias Differential Method,” The 13th Mechatronics Forum International Conference, Linz, 17-19 September 2012, pp. 399-403.
 T. Negishi, H. Nakane and E. Takada, “Fundamental Electronic Circuitry,” Corona Publishing, Tokyo, 1998.
 J. Englebert, T. Nguyen and C. Thurston, “B2 Spice A/D 2000 Japanese Manual,” 3rd Edition, Sora Computer Products, Tokyo, 2001.