US6263091B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method for identifying foreground and background portions of digitized images
Assignee: Uniloc 2017 LLC
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Filing: 1998-02-25
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Granted: 2001-07-17
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Expires: 2018-02-25
Abstract
Abstract Disclosed in a system and method for segmenting foreground pixel from background pixels in a digital image, specifically a fingerprint image. First the image is divided into blocks of optimal size. Then, for a given block, an overall gradient magnitude and a projected gradient magnitude is determined. The overall gradient magnitude is a measure of the amount of intensity variation in the current block. If a large number (or all) of the pixels have a direction that is the same as the overall gradient direction, the projected gradient magnitude will be nearly equal (will be equal) to the overall gradient magnitude. This indicates that the current block is a block in the foreground of the image. A relationship, e.g., a ratio, of the over gradient magnitude to the overall projected gradient magnitude is taken certainty level that the current block is in the foreground or background of the image. Connected blocks making up the largest region of foreground blocks are considered the foreground region, the rest of the blocks/regions are discarded (considered as background).
Inventors
- 👤 Anil K. Jain
- 👤 Lin Hong
- 👤 Rudolf Maarten Bolle
- 👤 Sharathchandra Umapathirao Pankanti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:05
CPC Classifications
G; G06; G06V; G06V40/00; G06V40/10; G06V40/12; G06V40/1347; G06V40/1365
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
152 words
A method for segmenting a foreground and background region in a digital image in a computer system, said image including a plurality of image pixels, comprising the steps of: dividing the image into a plurality of blocks; estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, and further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient direction; determining an overall intensity gradient magnitude for said selected block; determining a vector component of the overall intensity gradient magnitude for said selected block in said overall intensity gradient direction for said selected block; and comparing said overall intensity gradient magnitude for said selected block to said vector component for said selected block to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
Claim 2
Independent Claim
152 words
A method for segmenting a foreground and background region in a digital image in a computer system, said image including a plurality of image pixels, comprising the steps of: dividing the image into a plurality of blocks; estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, and further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient direction; determining an overall intensity gradient magnitude for said selected block; determining a vector component of the overall intensity gradient magnitude for said selected block in said overall intensity gradient direction for said selected block; and comparing said overall intensity gradient magnitude for said selected block to said vector component for said selected block to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
Claim 3
Independent Claim
153 words
A system for segmenting a foreground and background region in a digital image in a computer system, said image comprising a compilation of pixels, comprising: means for dividing the image into a plurality of blocks; means for estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, and further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient; means for determining an overall intensity gradient magnitude for said selected block; means for determining a vector component of the overall intensity gradient magnitude for said selected block in said overall intensity gradient direction for said selected block; and means for comparing said overall intensity gradient magnitude for said selected block to said vector component to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
Claim 4
Independent Claim
153 words
A system for segmenting a foreground and background region in a digital image in a computer system, said image comprising a compilation of pixels, comprising: means for dividing the image into a plurality of blocks; means for estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, and further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient; means for determining an overall intensity gradient magnitude for said selected block; means for determining a vector component of the overall intensity gradient magnitude for said selected block in said overall intensity gradient direction for said selected block; and means for comparing said overall intensity gradient magnitude for said selected block to said vector component to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
Claim 5
Independent Claim
237 words
A system for determining segmenting a foreground and background region in a digital image in computer system, comprising: a computer with a memory, a central processing unit, and a database of one or more images, the images having a plurality of pixels, the image partitioned into one or more blocks of one or more of the pixels, each of the blocks having a size; a block direction process, executed by the central processing unit, that determines a line orientation of one or more lines within one or more of the blocks, the block direction process determining a block orientation of the block based on the line orientations within the block, the block direction process further determining an overall gradient direction; a segmentation process, executed by the central processing unit, that determines an overall gradient magnitude that is a measure of the amount of intensity variation in the current block and an overall projected gradient magnitude being a vector component of the overall gradient magnitude on the overall gradient direction, the segmentation process using a relationship between the overall gradient magnitude and the overall projected gradient magnitude in a respective block to determine whether or not the respective block is in the foreground of the digital image; and wherein the relationship is a certainty level based on the ratio of a monotonic function of the overall projected gradient magnitude to a monotonic function of the overall gradient magnitude.
Claim 6
Independent Claim
237 words
A system for determining segmenting a foreground and background region in a digital image in computer system, comprising: a computer with a memory, a central processing unit, and a database of one or more images, the images having a plurality of pixels, the image partitioned into one or more blocks of one or more of the pixels, each of the blocks having a size; a block direction process, executed by the central processing unit, that determines a line orientation of one or more lines within one or more of the blocks, the block direction process determining a block orientation of the block based on the line orientations within the block, the block direction process further determining an overall gradient direction; a segmentation process, executed by the central processing unit, that determines an overall gradient magnitude that is a measure of the amount of intensity variation in the current block and an overall projected gradient magnitude being a vector component of the overall gradient magnitude on the overall gradient direction, the segmentation process using a relationship between the overall gradient magnitude and the overall projected gradient magnitude in a respective block to determine whether or not the respective block is in the foreground of the digital image; and wherein the relationship is a certainty level based on the ratio of a monotonic function of the overall projected gradient magnitude to a monotonic function of the overall gradient magnitude.
Claim 7
Dependent Claim
190 words
A computer system for segmenting a foreground region in a digital image, comprising: a memory, for storing a database of one or more images, the images having a plurality of pixels, each of said images partitioned into one or more blocks consisting of one or more of said pixels; a block direction processing unit for estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, said block direction processing unit further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient; and a segmentation processing unit, for measuring the amount of intensity variation in said block to obtain an overall gradient magnitude for said selected block and a vector component of the overall gradient magnitude for said selected block in said overall gradient direction for said selected block, the segmentation processing unit further comparing said overall intensity gradient magnitude for said selected block to said vector component for said selected block to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
Claim 8
Dependent Claim
190 words
A computer system for segmenting a foreground region in a digital image, comprising: a memory, for storing a database of one or more images, the images having a plurality of pixels, each of said images partitioned into one or more blocks consisting of one or more of said pixels; a block direction processing unit for estimating an intensity gradient direction at each pixel in a selected one of said plurality of blocks, said block direction processing unit further determining an overall intensity gradient direction for said selected block based on said pixel intensity gradient; and a segmentation processing unit, for measuring the amount of intensity variation in said block to obtain an overall gradient magnitude for said selected block and a vector component of the overall gradient magnitude for said selected block in said overall gradient direction for said selected block, the segmentation processing unit further comparing said overall intensity gradient magnitude for said selected block to said vector component for said selected block to identify the selected block as in the foreground of the digital image, when said vector component is substantially equal to the overall intensity gradient magnitude.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-07-16 | 2005-01-15 | 2005-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-07-16 | 2009-01-15 | 2009-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-07-16 | 2013-01-15 | 2013-07-17 | $7700.00 | Window Closed / Lapsed |