ACCELERATION-CORRECTED BARCODE VERIFICATION
In one embodiment, barcode widths and barcode space widths are estimated using a first light source separated by a known distance from a second light source. The estimations are determined by scanning the first and second light sources over a barcode while detecting a corresponding first reflected light beam and a second reflected light beam from the scanned barcode; processing the first reflected light beam to determine first barcode edge detections; processing the second reflected light beam to determine second barcode edge detections; estimating a first acceleration for the scanning; estimating a second acceleration for the scanning, wherein the second acceleration is substantially orthogonal to the first acceleration; deriving an overall velocity for the scanning by integrating the first and second accelerations; and comparing the first edge detections to the second edge detections using the overall velocity to derive the barcode widths and spaces.
1 . A method of estimating barcode widths and barcode space widths using a first light source separated by a known distance from a second light source, comprising:
scanning the first and second light sources over a barcode while detecting a corresponding first, reflected light beam and a second reflected light beam from the scanned barcode;
processing the first reflected light beam to determine first barcode edge detections;
processing the second reflected light beam to determine second barcode edge detections;
estimating a first acceleration for the scanning;
estimating a second acceleration for the scanning, wherein the second acceleration is substantially orthogonal to the first acceleration;
deriving an overall velocity for the scanning using first and second accelerations; and
comparing the first edge detections to the second edge detections using the overall velocity to derive the barcode widths and barcode space widths.
2 . The method of claim 1 , wherein the first and second accelerations are estimated using orthogonally-arranged accelerometers.
3 . The method of claim 1 , wherein deriving the overall velocity comprises:
integrating the first acceleration to provide a first velocity;
integrating the second acceleration to provide a second velocity;
squaring the first velocity to provide a first square;
squaring the second velocity to provide a second square;
summing the first and second squares to provide a sum; and
taking the square root of the sum to provide the overall velocity.
4 . The method of claim 1 , wherein the scanning comprises manual scanning.
5 . The method of claim 1 , wherein the scanning comprises machine scanning.
6 . A barcode verifier apparatus, comprising;
a first photodetector;
a second photodetector separated from the first photodetector by a known distance along a first axis;
a first accelerometer arranged to detect an acceleration along the first axis; and a
a second accelerometer arranged to detect an acceleration along a second axis substantially orthogonal to the first axis.
7 . The barcode verifier apparatus of claim 6 , further comprising: a first light source arranged to direct a light beam at a scanned barcode such that a first reflected light may be detected by the first photodetector; and a second light source arranged to direct a light beam at the scanned barcode such that a second reflected light may be detected by the second photodetector.
8 . The barcode verifier apparatus of claim 6 , further comprising a processor adapted to integrate an acceleration from each of the accelerometers so as to determine a first velocity along the first axis and a second velocity along the second axis.
9 . The barcode verifier apparatus of claim 8 , wherein the processor is further adapted to determine an overall velocity from the first and second velocities.
10 . The barcode verifier apparatus of claim 9 , wherein the processor is further adapted to determine barcode widths and barcode space widths using the overall velocity.
11 . The barcode verifier apparatus of claim 6 , wherein the first and second light sources comprise laser sources.
12 . The barcode verifier apparatus of claim 6 , wherein the first and second light sources comprise LED sources.
13 . A barcode verifier, comprising;
means for determining accelerations during a barcode scan; and
means for using the determined accelerations and detected barcode edges from the barcode scan for determining barcode widths and barcode space widths for a scanned barcode.
14 . The barcode verifier of claim 13 , wherein the means for determining accelerations during a barcode scan comprises an accelerometer.
15 . The barcode verifier of claim 14 , wherein the means for determining accelerations comprises a first accelerometer and a second accelerometer.
16 . The barcode verifier of claim 15 , wherein the first accelerometer and the second accelerometer are arranged to detect substantially orthogonal accelerations.
17 . The barcode verifier of claim 16 , further comprising:
a first photodetector; and
a second photodetector separated from the first photodetector by a known distance along a first axis, wherein the first accelerometer is arranged to determine an acceleration along the first axis.
18 . The barcode verifier of claim 17 , further comprising; a first light source adapted to provide a reflected light from the barcode to the first photodetector and a second light source adapted to provide a reflected light from the barcode to the second photodetector.
19 . The barcode verifier of claim 18 , wherein the first and second light sources comprise laser sources.
20 . The barcode verifier of claim 18 , wherein the first and second light sources comprise LED sources.