Method and apparatus for rapid and precision detection of omnidirectional postnet barcode location
First Claim
1. A method for detecting an omnidirectional postnet bar code on an object by digital signal processing, comprising the steps of:
- acquiring a two-dimensional digital image of said omnidirectional postnet bar code, said two-dimensional digital image being represented by a plurality of color-coded pixels;
filtering said two-dimensional digital image with a means for filtering to remove a plurality of non-black coded pixels from said plurality of color-coded pixels and provide a filtering output;
saving said filtering output in a memory device;
dilating said two-dimensional digital image to form a block dominated by a plurality of black-colored pixels;
providing a down sampled image Gm;
match-filtering said down-sampled image Gm with a set of two-dimensional matched filters to indicate a best-matched filter;
determining a an omnidirectional postnet bar code location;
associating a plurality of matched filters with an orientation angle of said omnidirectional postnet bar code;
generating a plurality of coefficients from said match-filtering step during a feature template step;
identifying a gravity center for each of a plurality of short bar codes and connecting said gravity centers to form a straight line;
comparing said straight line with said omnidirectional postnet bar code location to generate a verification result; and
detecting a position and an orientation of said omnidirectional postnet bar code location by matching said omnidirectional postnet bar code location with said verification result.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for rapid and precise detecting of an omnidirectional postnet bar code on an object by digital signal processing is provided. In order to rapidly and accurately detect omnidirectional postnet bar codes, a two-dimensional digital image containing the postnet bar code is acquired, filtered and dilated to form a block dominated by a plurality of black-colored pixels. Then a down sampled image is provided and match filtered with a two-dimensional matched filtering output to indicate a best-matched filter, thus determining a postnet bar code location and orientation by associating matched filters with an orientation angle of the omnidirectional postnet bar code. The method further comprises the steps of identifying a gravity center for each short bar code and connecting the gravity centers to form a straight line by using a Hough transform and comparing the straight line with the postnet bar code location to generate a verification result and then detecting a position and an orientation of said postnet bar code location by matching said postnet bar code location with said verification result.
67 Citations
39 Claims
-
1. A method for detecting an omnidirectional postnet bar code on an object by digital signal processing, comprising the steps of:
-
acquiring a two-dimensional digital image of said omnidirectional postnet bar code, said two-dimensional digital image being represented by a plurality of color-coded pixels;
filtering said two-dimensional digital image with a means for filtering to remove a plurality of non-black coded pixels from said plurality of color-coded pixels and provide a filtering output;
saving said filtering output in a memory device;
dilating said two-dimensional digital image to form a block dominated by a plurality of black-colored pixels;
providing a down sampled image Gm;
match-filtering said down-sampled image Gm with a set of two-dimensional matched filters to indicate a best-matched filter;
determining a an omnidirectional postnet bar code location;
associating a plurality of matched filters with an orientation angle of said omnidirectional postnet bar code;
generating a plurality of coefficients from said match-filtering step during a feature template step;
identifying a gravity center for each of a plurality of short bar codes and connecting said gravity centers to form a straight line;
comparing said straight line with said omnidirectional postnet bar code location to generate a verification result; and
detecting a position and an orientation of said omnidirectional postnet bar code location by matching said omnidirectional postnet bar code location with said verification result. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
16. The method for detecting an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 15, further comprising the step of calculating a plurality of moments and a plurality of inertials from the plurality of short bar codes.
-
17. The method for detecting an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 16, wherein packages are rapidly sorted into zip codes.
-
18. The method for detecting an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 17, further comprising automating said steps with computer equipment.
-
19. The method for detecting an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 11, further comprising the step of acquiring said two-dirnensional digital image by photographing said object.
-
20. A computer-readable medium whose contents cause a computer system to detect an omnidirectional postnet bar code on an object by digital signal processing, comprising:
-
a means for image acquisition generates a two-dimensional digital image of said omnidirectional postnet bar code;
said digital image further comprising a plurality of color-coded pixels;
said omnidirectional postnet bar code having a plurality of short bars;
a means for filtering removes a plurality of non-black coded pixels from said plurality of color-coded pixels to provide a filtering output, said filtering output being saved to a memory device of said computer system;
a means for dilating said two-dimensional digital image forms a block dominated by a plurality of black-colored pixels;
a means for down-sampling provides a down sampled image Gm;
a means for matched filtering processes said down-sampled image Gm to provide a best-matched filter;
said best-matched filter determines said omnidirectional postnet bar code location;
said matched filtering means associates a plurality of matched filters with an orientation angle of said omnidirectional postnet bar code;
a feature template means generates a plurality of coefficients;
each of said plurality of short bar codes having a gravity center;
a means for Hugh transform connects said gravity centers to form a straight line, said straight line being compared with said omnidirectional postnet bar code location to generate said verification result; and
said verification result is matched with said omnidirectional postnet bar code location by a means for orientation to detect a position and said orientation of said omnidirectional postnet bar code location. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
28. The computer-readable medium whose contents cause a computer system to detect an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 27, wherein packages are rapidly sorted into zip codes.
-
29. The computer-readable medium whose contents cause a computer system to detect an omnidirectional postnet bar code on an object by digital signal processing, as recited in claim 24, further comprising a linear rotation after said plurality of coefficients are generated.
-
30. A storage medium encoded with machine-readable computer program code whose contents cause a computer system to detect a position and orientation of an omnidirectional postnet bar code on an object by digital signal processing to match a omnidirectional postnet bar code location with a verification result, comprising:
-
a means for image acquisition generates a two-dimensional digital image of said omnidirectional postnet bar code;
said two-dimensional digital image further comprising a plurality of color-coded pixels;
said omnidirectional postnet bar code having a plurality of short bar bars;
a means for filtering removes a plurality of non-black coded pixels from said plurality of color-coded pixels to provide a filtering output, said filtering output being saved to a memory device of said computer system;
a means for dilating said two-dimensional digital image forms a block dominated by a plurality of black-colored pixels;
a means for multi-grid image processing provides a down sampled image Gm;
a means for matched filtering match filters said down-sampled image Gm with a set of two-dimensional matched filters provides a best-matched filter;
said best-matched filter determines said omnidirectional postnet bar code location;
said matched filtering means associates a plurality of matched filters with an orientation angle of said omnidirectional postnet bar code;
a feature template means generates a plurality of coefficients;
each of said plurality of short bar codes having a gravity center;
a means for Hugh transform connects said gravity centers to form a straight line, said straight line being compared with said omnidirectional postnet bar code location to generate said verification result; and
said verification result is matched with said omnidirectional postnet bar code location to detect a position and said orientation of said omnidirectional postnet bar code location. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39)
-
-
38. The storage medium encoded with machine-readable computer program code whose contents cause a computer system to detect a position and orientation of an omnidirectional postnet bar code, as recited in claim 37, wherein packages are rapidly sorted into zip codes.
-
39. The storage medium encoded with machine-readable computer program code whose contents cause a computer system to detect a position and orientation of an omnidirectional postnet bar code, as recited in claim 34, further comprising a linear rotation after said plurality of coefficients are generated.
Specification