Standoff and mobile fingerprint collection
First Claim
Patent Images
1. A method, comprising:
- determining that a digital image contains a biometric identifier;
dividing the digital image into a grid of blocks;
computing a ridge orientation for each block containing a portion of the biometric identifier in the grid of blocks;
determining a bad block in the grid of blocks by applying a bad block heuristic, the bad block heuristic comparing the computed ridge orientation for each block containing the portion of the biometric identifier in the grid of blocks as a target block to the ridge orientation for each block directly adjacent to the target block and identifying the target block as a bad block if a deviation between the ridge orientation of the target block and ridge orientations of the directly adjacent blocks exceeds a certain threshold;
executing lighting compensation to remove a lighting effect from the biometric identifier, the lighting compensation being a piece-wise linear transformation of a light intensity for each block of the digital image that calculates an intensity height field of the each block in the grid of blocks and fits a separate plane to the calculated intensity height field for the each block;
processing the biometric identifier ignoring the identified bad blocks and after the lighting compensation is executed to create an identification profile; and
outputting the created identification profile in a format usable by a user.
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Abstract
A method, a biometric identifier collection device, and a set of instructions are disclosed. A memory 208 may store a digital image having a biometric identifier. A processor 204 may execute a lighting compensation to remove a lighting effect from the biometric identifier. The processor 204 may process the biometric identifier to create an identification profile.
23 Citations
17 Claims
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1. A method, comprising:
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determining that a digital image contains a biometric identifier; dividing the digital image into a grid of blocks; computing a ridge orientation for each block containing a portion of the biometric identifier in the grid of blocks; determining a bad block in the grid of blocks by applying a bad block heuristic, the bad block heuristic comparing the computed ridge orientation for each block containing the portion of the biometric identifier in the grid of blocks as a target block to the ridge orientation for each block directly adjacent to the target block and identifying the target block as a bad block if a deviation between the ridge orientation of the target block and ridge orientations of the directly adjacent blocks exceeds a certain threshold; executing lighting compensation to remove a lighting effect from the biometric identifier, the lighting compensation being a piece-wise linear transformation of a light intensity for each block of the digital image that calculates an intensity height field of the each block in the grid of blocks and fits a separate plane to the calculated intensity height field for the each block; processing the biometric identifier ignoring the identified bad blocks and after the lighting compensation is executed to create an identification profile; and outputting the created identification profile in a format usable by a user. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A biometric identifier collection device, comprising:
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a memory that stores a digital image having a biometric identifier; a processor that is programmed to; divide the digital image into a grid of blocks, compute a ridge orientation for each block containing a portion of the biometric identifier in the grid of blocks, determine a bad block in the grid of blocks by applying a bad block heuristic, the bad block heuristic comparing the computed ridge orientation for each block containing the portion of the biometric identifier in the grid of blocks as a target block to the ridge orientation for each block directly adjacent to the target block and identifying the target block as a bad block if a deviation between the ridge orientation of the target block and ridge orientations of the directly adjacent blocks exceeds a certain threshold, execute a lighting compensation to remove a lighting effect from the biometric identifier, the lighting compensation being a piece-wise linear transformation of a light intensity for each block of the digital image that calculates an intensity height field of the each block in the grid of blocks and fits a separate plane to the calculated intensity height field for the each block, and process the biometric identifier ignoring the identified bad blocks and after the lighting compensation is executed to create an identification profile; and an output device that outputs the created identification profile in a format usable by a user. - View Dependent Claims (10, 11, 12, 13)
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14. A non-transitory storage medium on which is recorded a set of instructions executable by a processor to implement a method for processing digital images, the method comprising:
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determining that a digital image contains a biometric identifier; dividing the digital image into a grid of blocks; computing a ridge orientation for each block containing a portion of the biometric identifier in the grid of blocks; determining a bad block in the grid of blocks by applying a bad block heuristic, the bad block heuristic comparing the computed ridge orientation for each block containing the portion of the biometric identifier in the grid of blocks as a target block to the ridge orientation for each block directly adjacent to the target block and identifying the target block as a bad block if a deviation between the ridge orientation of the target block and ridge orientations of the directly adjacent blocks exceeds a certain threshold; executing lighting compensation to remove a lighting effect from the biometric identifier, the lighting compensation being a piece-wise linear transformation of a light intensity for each block of the digital image that calculates an intensity height field of the each block in the grid of blocks and fits a separate plane to the calculated intensity height field for the each block; and processing the biometric identifier ignoring the identified bad blocks and after the lighting compensation is executed to create an identification profile; and outputting the created identification profile in a format usable by a user. - View Dependent Claims (15, 16, 17)
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Specification