Laser scanner for reading two dimensional bar codes

Claim 1

A system for reading a bar code symbol, said symbol having at least one group of elements, comprising a hand-held scanning unit in a lightweight, portable housing comprising: (a) a light source for generating light beam directed toward a target area including a symbol to be read; (b) means for optically modifying and directing the light beam along an optical path toward said symbol located in the vicinity of a reference plane exterior to said scanning unit and for scanning spatially adjacent portions of said reference plane; (c) a photo detector component having a field of view and operative for detecting light of variable intensity reflected off said target area and for generating electrical signals indicative of the detected intensity; (d) means for converting said electrical signals into digital representations thereof, the digital representations embodying a bit map image of said target area; (e) means for storing said digital representations in addressable storage medium; (f) means for accessing said storage medium in an address sequence corresponding to a linear scan through the bit map image and processing each pixel in such linear scan to determine the presence in the bit map image of at least one group of elements of said symbol included within the field of view of said photo detector component; and (g) means for automatically changing said address sequence to a second linear scan if said linear scan results in recognizing only a portion of a group of elements of said symbol.

Claim 2

A system for reading a bar code symbol, said symbol having at least one group of elements, comprising a hand-held scanning unit in a lightweight, portable housing comprising: (a) a light source for generating light beam directed toward a target area including a symbol to be read; (b) means for optically modifying and directing the light beam along an optical path toward said symbol located in the vicinity of a reference plane exterior to said scanning unit and for scanning spatially adjacent portions of said reference plane; (c) a photo detector component having a field of view and operative for detecting light of variable intensity reflected off said target area and for generating electrical signals indicative of the detected intensity; (d) means for converting said electrical signals into digital representations thereof, the digital representations embodying a bit map image of said target area; (e) means for storing said digital representations in addressable storage medium; (f) means for accessing said storage medium in an address sequence corresponding to a linear scan through the bit map image and processing each pixel in such linear scan to determine the presence in the bit map image of at least one group of elements of said symbol included within the field of view of said photo detector component; and (g) means for automatically changing said address sequence to a second linear scan if said linear scan results in recognizing only a portion of a group of elements of said symbol.

Claim 6

An apparatus for detecting indicia including a plurality of groups of elements of different light reflectivity, comprising: (a) a light source for emitting a light beam; (b) an optical component disposed in the path of said beam for optically modifying and directing the light beam along an optical path toward a target located in the vicinity of a reference plane lying in said optical path so as to scan spatially adjacent elements of groups in said reference plane in a first scan direction; (c) sensor means having a field of view operative for detecting light of variable intensity reflected off said target, and for generating an electrical image of said field of view of said sensor means; (d) means for storing said electrical image in an addressable storage medium; (e) means for performing a linear scan of said electrical image in said addressable storage medium; and (f) means for changing said linear scan of said electrical image to a different linear scan if a partial but not complete group of elements is recognized by the linear scan of step (e).

Claim 7

An apparatus for detecting indicia including a plurality of groups of elements of different light reflectivity, comprising: (a) a light source for emitting a light beam; (b) an optical component disposed in the path of said beam for optically modifying and directing the light beam along an optical path toward a target located in the vicinity of a reference plane lying in said optical path so as to scan spatially adjacent elements of groups in said reference plane in a first scan direction; (c) sensor means having a field of view operative for detecting light of variable intensity reflected off said target, and for generating an electrical image of said field of view of said sensor means; (d) means for storing said electrical image in an addressable storage medium; (e) means for performing a linear scan of said electrical image in said addressable storage medium; and (f) means for changing said linear scan of said electrical image to a different linear scan if a partial but not complete group of elements is recognized by the linear scan of step (e).

Claim 13

A system for reading a bar code symbol, said symbol having at least one row, comprising: a hand-held scanning unit in a lightweight, portable housing including (i) a light source for generating a light beam directed toward a symbol to be read; (ii) means for optically modifying and directing the light beam along an optical path toward said symbol located in the vicinity of a reference plane exteriorly of the scanning trait and for scanning spatially adjacent portions of said reference plane; (iii) a photodetector component having a field of view and operative for detecting at least a portion of light of variable intensity reflected off the symbol and for generating electrical signals indicative of the detected intensity; (iv) means for converting said electrical signals into digital representations thereof, the digital representations embodying a bit-map image of the field of view of said photodetector component; (v) means for storing said digital representations in an addressable storage medium; and (vi) means for accessing said storage means in an address sequence corresponding to a linear scan through the bit-map image and determining if a row of the bit-map image corresponds to a row of the symbol; and (vii) means responsive to said determining for automatically changing said accessing to a second address sequence if said linear scan recognizes a partial row of said symbol.

Claim 14

A system for reading a bar code symbol, said symbol having at least one row, comprising: a hand-held scanning unit in a lightweight, portable housing including (i) a light source for generating a light beam directed toward a symbol to be read; (ii) means for optically modifying and directing the light beam along an optical path toward said symbol located in the vicinity of a reference plane exteriorly of the scanning trait and for scanning spatially adjacent portions of said reference plane; (iii) a photodetector component having a field of view and operative for detecting at least a portion of light of variable intensity reflected off the symbol and for generating electrical signals indicative of the detected intensity; (iv) means for converting said electrical signals into digital representations thereof, the digital representations embodying a bit-map image of the field of view of said photodetector component; (v) means for storing said digital representations in an addressable storage medium; and (vi) means for accessing said storage means in an address sequence corresponding to a linear scan through the bit-map image and determining if a row of the bit-map image corresponds to a row of the symbol; and (vii) means responsive to said determining for automatically changing said accessing to a second address sequence if said linear scan recognizes a partial row of said symbol.

Claim 18

A method for reading a symbol, the symbol comprising at least one recognizable code pattern, comprising the steps of: (a) directing a light beam from a light source in a scanning pattern over a symbol to be read; (b) detecting at least a portion of light of variable intensity reflected off the symbol over a field of view and generating digital data representative of the detected light intensity; (c) transferring the digital data to a memory array such that a digital bitmapped image of the field of view is obtained; (d) outputting a portion of the digital bitmapped image data from the memory array in such a manner that a scan of the bitmapped image of at least a portion of a scan line is obtained; (e) processing said outputted portion of said digital bitmapped image data to determine if a code pattern of an entire row of a bar code symbol was scanned; and (f) changing said outputting of a portion of the digital bitmapped image data if it is determined that a code pattern of a partial row of a bar code symbol was obtained in the output from the memory array.

Claim 19

A method for reading a symbol, the symbol comprising at least one recognizable code pattern, comprising the steps of: (a) directing a light beam from a light source in a scanning pattern over a symbol to be read; (b) detecting at least a portion of light of variable intensity reflected off the symbol over a field of view and generating digital data representative of the detected light intensity; (c) transferring the digital data to a memory array such that a digital bitmapped image of the field of view is obtained; (d) outputting a portion of the digital bitmapped image data from the memory array in such a manner that a scan of the bitmapped image of at least a portion of a scan line is obtained; (e) processing said outputted portion of said digital bitmapped image data to determine if a code pattern of an entire row of a bar code symbol was scanned; and (f) changing said outputting of a portion of the digital bitmapped image data if it is determined that a code pattern of a partial row of a bar code symbol was obtained in the output from the memory array.

Claim 22

A method of reading a symbol containing light variable elements arranged in multiple rows comprising the steps of: (a) directing a light beam across a target area containing said symbol in a pattern sufficient to capture all elements contained in said target area; (b) creating an electrical image of reflected light of varying intensity from said target area; (c) storing said electrical image in an addressable storage medium; (d) processing said electrical image by performing a linear scan of said addressable storage medium in an effort to read said symbol; (e) manipulating said linear scan of said addressable storage medium until the entire row of said symbol is recognized; and (f) continuing the linear scan for which an entire row of said symbol was recognized, until the entire symbol is read.

Claim 23

A method of reading a symbol containing light variable elements arranged in multiple rows comprising the steps of: (a) directing a light beam across a target area containing said symbol in a pattern sufficient to capture all elements contained in said target area; (b) creating an electrical image of reflected light of varying intensity from said target area; (c) storing said electrical image in an addressable storage medium; (d) processing said electrical image by performing a linear scan of said addressable storage medium in an effort to read said symbol; (e) manipulating said linear scan of said addressable storage medium until the entire row of said symbol is recognized; and (f) continuing the linear scan for which an entire row of said symbol was recognized, until the entire symbol is read.

Claim 26

A method for scanning a bar code symbol having a plurality of discrete groups of information containing elements of different light reflectivity on a target, comprising the steps of: (a) directing a light beam in a scanning pattern over a target area containing a symbol to be read; (b) detecting reflected light of variable intensity reflected off said target area; (c) generating electrical signals indicative of said detected light of variable intensity; (d) converting said electrical signals into digital representations thereof, said digital representations comprising a bit map image of said target area; (e) storing said digital representations in an addressable storage medium; (f) accessing said addressable storage medium in a first address sequence corresponding to a first linear scan through said bit map image; (g) processing each pixel in said linear scan to determine the presence in said bit map image of at least a portion of one group of elements of said symbol; (h) changing said address sequence to create a different linear scan through said bit map image if less than all of a group of elements of said symbol was determined to be present; (i) processing each pixel in said different linear scan to determine the presence in said bit map image of at least a portion of one group of elements of said symbol; (j) repeating steps (g) and (h) until an entire group of elements of said symbol is recognized; and (k) continuing the linear scan for which an entire group of elements of said symbol was recognized.

Claim 27

A method for scanning a bar code symbol having a plurality of discrete groups of information containing elements of different light reflectivity on a target, comprising the steps of: (a) directing a light beam in a scanning pattern over a target area containing a symbol to be read; (b) detecting reflected light of variable intensity reflected off said target area; (c) generating electrical signals indicative of said detected light of variable intensity; (d) converting said electrical signals into digital representations thereof, said digital representations comprising a bit map image of said target area; (e) storing said digital representations in an addressable storage medium; (f) accessing said addressable storage medium in a first address sequence corresponding to a first linear scan through said bit map image; (g) processing each pixel in said linear scan to determine the presence in said bit map image of at least a portion of one group of elements of said symbol; (h) changing said address sequence to create a different linear scan through said bit map image if less than all of a group of elements of said symbol was determined to be present; (i) processing each pixel in said different linear scan to determine the presence in said bit map image of at least a portion of one group of elements of said symbol; (j) repeating steps (g) and (h) until an entire group of elements of said symbol is recognized; and (k) continuing the linear scan for which an entire group of elements of said symbol was recognized.

Claim 31

A method for scanning a bar code symbol having a plurality of rows of data comprising the steps of: (a) scanning a light beam over a target area containing a symbol to be read; (b) creating a digital representation of reflected light from said target area; (c) storing said digital representation in memory; (d) accessing said memory in a linear scan; (e) determining for each scan line whether a portion of a row of said symbol has been recognized; (f) changing said linear scan of said memory to a different scan path if only a portion of a row of said symbol was recognized in step (e); (g) repeating steps (d)-(f) until an entire row of said symbol is recognized; and continuing said linear scan with which an entire row was recognized.

Claim 32

A method for scanning a bar code symbol having a plurality of rows of data comprising the steps of: (a) scanning a light beam over a target area containing a symbol to be read; (b) creating a digital representation of reflected light from said target area; (c) storing said digital representation in memory; (d) accessing said memory in a linear scan; (e) determining for each scan line whether a portion of a row of said symbol has been recognized; (f) changing said linear scan of said memory to a different scan path if only a portion of a row of said symbol was recognized in step (e); (g) repeating steps (d)-(f) until an entire row of said symbol is recognized; and continuing said linear scan with which an entire row was recognized.