US 7,526,130 B2
Signal processing in barcode reading with a wavelet transformation
Hiroshi Hayakawa, Saitamai (Japan); Susumu Nakano, Hamura (Japan); and Kentaro Takahashi, Tokoroza (Japan)
Assigned to Optoelectronics Co., Ltd., Warabi, Saitama Pref. (Japan)
Filed on Oct. 18, 2005, as Appl. No. 11/253,013.
Prior Publication US 2007/0086670 A1, Apr. 19, 2007
Int. Cl. G06K 9/18 (2006.01)
U.S. Cl. 382—183  [382/260; 382/275; 382/276] 8 Claims
OG exemplary drawing
 
1. A method for processing a digital signal obtained in a barcode reading operation, comprising the steps of applying a wavelet transformation to said digital signal; determining a threshold for coefficients for each level in said wavelet transformation, and setting said coefficients as zero if lower than said threshold
wherein said digital signal is obtained by analogue-to-digital conversion of an analogue signal obtained in said barcode reading operation, and said threshold is calculated based on a total transfer function H(ω) of a analogue processing stage for processing said analogue signal.