Adaptive thresholding for image recognition
First Claim
1. A computer-implemented method comprising:
- under control of one or more computer systems configured with executable instructions,obtaining an image captured by a camera of a portable computing device, the image including pixel values for a plurality of pixels of the camera;
identifying one or more potential edge locations within a region of the image by analyzing one or more image intensity gradients within the region;
analyzing pixel values of a set of pixels on opposing sides of the one or more potential edge locations to determine a character pixel value and a background pixel value for the region;
based at least in part on the character pixel value and the background pixel value for the region, determining a character pixel value threshold for the region; and
determining one or more character portions within the region based at least in part upon whether pixel values for pixels in the region are above or below the character pixel value threshold.
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Abstract
Various approaches for providing textual information to an application, system, or service are disclosed. In particular, various embodiments enable a user to capture an image with a camera of a portable computing device. The computing device is capable of taking the image and processing it to recognize, identify, and/or isolate the text in order to forward the text to an application or function. The application or function can then utilize the text to perform an action in substantially real-time. The text may include an email, phone number, URL, an address, and the like and the application or function may be dialing the phone number, navigating to the URL, opening an address book to save contact information, displaying a map to show the address, and so on. Adaptive thresholding can be used to account for variations across an image, in order to improve the accuracy and efficiency of text recognition processes.
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Citations
26 Claims
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1. A computer-implemented method comprising:
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under control of one or more computer systems configured with executable instructions, obtaining an image captured by a camera of a portable computing device, the image including pixel values for a plurality of pixels of the camera; identifying one or more potential edge locations within a region of the image by analyzing one or more image intensity gradients within the region; analyzing pixel values of a set of pixels on opposing sides of the one or more potential edge locations to determine a character pixel value and a background pixel value for the region; based at least in part on the character pixel value and the background pixel value for the region, determining a character pixel value threshold for the region; and determining one or more character portions within the region based at least in part upon whether pixel values for pixels in the region are above or below the character pixel value threshold. - View Dependent Claims (2, 3, 4)
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5. A computer-implemented method comprising:
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under control of one or more computer systems configured with executable instructions, analyzing one or more intensity gradients of a region in an image to identify one or more potential edge locations, the image including pixel values for a plurality of pixels; analyzing pixel values for a set of pixels within a determined distance of the one or more potential edge locations; determining a character pixel value threshold for the region based at least in part upon the pixel values within the determined distance of each of the one or more potential edge locations; and determining one or more character portions based at least in part upon a portion of the set of pixels having a pixel value at least meeting the character pixel value threshold. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A portable computing device, comprising:
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a processor; and a memory device including instructions that, when executed by the processor, cause the processor to; analyze one or more intensity gradients of a region in an image to identify one or more potential character edge locations; analyze pixel values for a set of pixels within a determined distance of the one or more potential edge locations; determine a character pixel value threshold for the region based at least in part upon the pixel values within the determined distance of each of the one or more edge locations; and determine one or more character portions based at least in part upon a portion of the set of pixels having a pixel value at least meeting the character pixel value threshold. - View Dependent Claims (16, 17, 18)
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19. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to:
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analyze one or more intensity gradients of a region in an image to identify one or more potential edge locations, the image including pixel values for a plurality of pixels; analyze pixel values for a set of pixels of the image within a determined distance of the one or more potential edge locations; determine a character pixel value threshold for the region based at least in part upon the pixel values within the determined distance of each of the one or more potential edge locations; and determine one or more character portions based at least in part upon a portion of the set of pixels having a pixel value at least meeting the character pixel value threshold. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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Specification