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AssigneeSpectra-Physics Scanning Systems, Inc.
InventorsBryan L. Olmstead, Michael J. Ahten, Bruce E. Paris, Jorge L. Acosta, James W. Ring, Paul R. Huss, Jon P. C. Williams, Alexander M. McQueen, Randy L. Person
Estimating the term…
A method and apparatus for reading bar codes or other images while reducing or eliminating the need for self-generated illumination. An image reader is preferably embodied as a handheld unit and comprises an efficient optical collection system including an aperture with a high aspect ratio and/or a multi-focal lens or lenses. An optically transmissive spacer affixed to the front of the handheld unit allows ambient light to be collected at close range, and a diffuser may be used to reflect ambient light from the handheld unit to provide additional illumination at close range. A masked CCD detector with rectangular pixels receives collected light and is coupled to an adaptive exposure circuit for preventing saturation of the CCD detector at high illumination levels. A correlated double sampling circuit coupled to the adaptive exposure circuit rejects common mode noise and allows operation in lower light levels. The correlated double sampling circuit is connected to a signal processor which uses a derivative based technique for detecting edges of the image. A decoder uses the edge detection information to decode encoded information from the image.
An optical reader comprising:
An optical reader comprising:
An optical reader comprising:
A handheld bar code reader comprising:
A bar code reader comprising:
Dependencies are inferred from the claim text.