Omnidirectional scanning method and apparatus
AssigneeSpectra-Physics Scanning Systems, Inc.
InventorsCraig D. Cherry, Robert J. Actis
Life of this patent
Estimating the term…
Abstract
A method and apparatus for reading encoded symbols such as bar code labels at any orientation to a raster scanning device. A pattern of virtual scan lines is selected over the two-dimensional imaging region according to the specifications of the images to be read. The pattern is generated by defining a family of parallel lines of a certain spacing and rotating the family by a specified angle until the two-dimensional imaging region is covered. Only the data at selected raster locations on the virtual scan lines is stored and processed. One-dimensional signal processing methods are used to detect edges and decode the encoded symbols.
Claims12
A method for reading a symbol having lighter and darker regions, comprising the steps of:
- collecting light reflected from a symbol;
- focusing said light onto a multi-dimensional imaging array, said multi-dimensional imaging array comprising a plurality of pixels;
- storing, in a plurality of digital arrays, information corresponding to the intensity of light detected at selected ones of said pixels, each digital array corresponding to one of a plurality of scan lines;
- separately for each digital array, converting said stored information into an analog signal;
- filtering said analog signal with a low pass filter to produce a filtered signal, said filtered signal having transitions in signal level corresponding to lighter and darker regions in said symbol;
- and
- detecting said transitions in said filtered signal.
A method for reading a symbol having lighter and darker regions, comprising the steps of:
- collecting light reflected from a symbol;
- focusing said light onto a multi-dimensional imaging array, said multi-dimensional imaging array comprising a plurality of pixels;
- storing, in a plurality of digital arrays, information corresponding to the intensity of light detected at selected ones of said pixels, each digital array corresponding to one of a plurality of scan lines;
- separately for each digital array, digitally interpolating said stored information to generate a digital signal having a higher sampling density than said stored information, said digital signal having transitions in signal level corresponding to lighter and darker regions in said symbol;
- and
- detecting said transitions in said digital signal.
A method for reading a symbol having lighter and darker regions, comprising the steps of:
- collecting light reflected from a symbol;
- focusing said light onto a multi-dimensional imaging array;
- storing, in a plurality of digital arrays, signal amplitude information corresponding to the intensity of light detected at selected sampling points, each digital array corresponding to one of a plurality of scan lines and comprising a sequence of signal samples;
- separately for each digital array, generating a digital signal of a higher sample density than said stored information by estimating a value of signal amplitude at points between said signal samples;
- and
- detecting transitions between relatively higher and relatively lower signal levels in said digital signal.
Dependencies are inferred from the claim text.