The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 2007
Filed:
May. 09, 2003
Mark Lucera, Pine Hill, NJ (US);
Frank Check, San Jose, CA (US);
C. Harry Knowles, Moorestown, NJ (US);
Xiaoxun Zhu, Philadelphia, PA (US);
Leroy Dickson, Morgan Hill, CA (US);
Mark Lucera, Pine Hill, NJ (US);
Frank Check, San Jose, CA (US);
C. Harry Knowles, Moorestown, NJ (US);
Xiaoxun Zhu, Philadelphia, PA (US);
LeRoy Dickson, Morgan Hill, CA (US);
Metrologic Instruments, Inc., Blackwood, NJ (US);
Abstract
The effects of paper/substrate noise are significantly reduced in multi-focal zone laser scanning systems by processing analog scan data signals with a scan data signal processor having a plurality of pass-band filters and amplifiers that are automatically selected for passing only the spectral components of an analog scan data signal produced when a bar code symbol is scanned at a particular focal zone in the laser scanning system. Two or more different pass-band filter structures can be provided for use in the scan data signal processor, wherein each pass-band filter structure is tuned to the spectral band associated with a particular focal zone in the laser scanning system. When a bar code symbol is scanned by a laser beam focused within the first focal zone or scanning range of the system, the pass-band filter structure associated with this focal zone or scanning range is automatically switched into operation. Only spectral components associated with the produced analog scan data signal and noise existing over this pass-band are allowed within the analog signal processor. By virtue of the present invention, first and second derivative signals can be generated and processed to produce a corresponding digital scan data signal for use in subsequent digitizing and decoe processing operations, without compromising system performance due to the destructive effects of thermal and substrate noise outside the spectral pass-band of interest for the bar code symbol being scanned.