Image transformation for indicia reading
First Claim
1. A method for reading an indicium, the method comprising:
- capturing an image of an object using a digital imager;
computing in real-time, using a dimensioning system, three-dimensional (3D) information corresponding to the object;
selecting an image-region-of-interest (image-ROI) in the image, the image-ROI containing at least a portion of the object;
creating an ideal-region-of-interest (ideal-ROI) using the 3D information corresponding to the portion of the object within the image-ROI, wherein dimensions of the ideal-ROI correspond to physical dimensions of the portion of the object contained in the image-ROI, and wherein the physical dimensions are determined using the 3D information;
transforming the portion of the image within the image-ROI into a corrected image within the ideal-ROI;
searching for an indicium in the corrected image; and
if an indicium can be found, then reading the indicium in the corrected image.
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Abstract
Obtaining a good image is important for reading indicia. Often, however, objects are not well aligned with an indicia reader'"'"'s digital imager. This misalignment may lead to images in which an indicium may appear distorted due to perspective. This perspective distortion makes indicia reading difficult. In general, perspective distortion of an imaged object may be corrected using knowledge of the true size, shape, and/or orientation of the physical object. The present invention embraces the use of a dimensioning system to obtain the 3D information necessary to provide this knowledge. Then, using this knowledge, to transform a distorted image of an indicium into a corrected image of the indicium without distortion. This corrected image may then be processed to read the undistorted indicium.
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Citations
19 Claims
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1. A method for reading an indicium, the method comprising:
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capturing an image of an object using a digital imager; computing in real-time, using a dimensioning system, three-dimensional (3D) information corresponding to the object; selecting an image-region-of-interest (image-ROI) in the image, the image-ROI containing at least a portion of the object; creating an ideal-region-of-interest (ideal-ROI) using the 3D information corresponding to the portion of the object within the image-ROI, wherein dimensions of the ideal-ROI correspond to physical dimensions of the portion of the object contained in the image-ROI, and wherein the physical dimensions are determined using the 3D information; transforming the portion of the image within the image-ROI into a corrected image within the ideal-ROI; searching for an indicium in the corrected image; and if an indicium can be found, then reading the indicium in the corrected image. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for removing perspective distortion from an image using three-dimensional (3D) information, the method comprising:
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capturing, using a digital imager, an image of a scene; computing in real time, using a dimensioning system, 3D information corresponding to the scene; selecting an image-region-of-interest (image-ROI) in the image; creating, using the 3D information corresponding to the portion of the scene within the image-ROI, an ideal-region-of-interest (ideal-ROI), wherein dimensions of the ideal-ROI correspond to physical dimensions of the portion of the scene within the image-ROI, and wherein the physical dimensions are determined using the 3D information; and transforming, the image in the image-ROI into a corrected image in the ideal-ROI to remove the perspective distortion. - View Dependent Claims (11, 12, 13)
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14. An indicia-reading system comprising:
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a dimensioning system to compute in real time 3D information about a scene, the dimensioning system comprising a pattern projector and a range camera; a digital imager to capture an image of the scene; and a processor communicatively coupled to the dimensioning system and the digital imager, the processor configured by software to; select an image-region-of-interest (image-ROI) within the image of the scene, the image-ROI containing a distorted indicium, transform the portion of the image within the image-ROI into a corrected image using 3D information corresponding to the portion of the scene within the image-ROI, the corrected image containing an undistorted indicium, and read the undistorted indicium in the corrected image. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification