Abstract
One of the most common methods of reading bar codes is to scan them with a laser beam and process the received optical signal. The received light is proportional to the integral of the beam profile multiplied by the region of the bar code covered by the beam. The finite spot size of the laser beam acts as a filter on the original bilevel bar code signal. This filtering can cause intersymbol interference between adjacent edges of the bar code signal. An edge detector attempts to reconstruct the original bilevel signal from this filtered signal. The edges detected in the filtered waveform are in different locations than those in the original bilevel bar code signal resulting in a distortion of the bar code signal. If this distortion is too large, it can prevent the bar code from being properly decoded. Thus, there is a limit on the spot size of the laser beam that can be used to scan a given density bar code.
Chapter PDF
References
A. Yariv, Optical Electronics. Holt, Rinehart, and Winston, 4th ed., 1991.
T. Pavlidis, J. Swartz, and Y. P. Wang, “Fundamentals of bar code information theory,” IEEE Computer, pp. 74–86, April 1990.
Uniform Code Council, Inc., UPC Symbol Specification Manual, January 1986.
E. Barkan and J. Swartz, “System design considerations in bar code laser scanning,” Optical Engineering, vol. 23, pp. 413–420, July/Aug. 1984.
S. Wolfram, Mathematica: A System for Doing Mathematics by Computer. Addison-Wesley, 2nd ed., 1991.
G. H. Golub and C. F. Van Loan, Matrix Computations. Johns Hopkins University Press, 1983.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1995 Springer Science+Business Media New York
About this chapter
Cite this chapter
Shellhammer, S.J. (1995). Distortion of Bar Code Signals in Laser Scanning. In: Lampropoulos, G.A., Chrostowski, J., Measures, R.M. (eds) Applications of Photonic Technology. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-9247-8_53
Download citation
DOI: https://doi.org/10.1007/978-1-4757-9247-8_53
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4757-9249-2
Online ISBN: 978-1-4757-9247-8
eBook Packages: Springer Book Archive