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US 8,571,346 B2Granted
Methods and devices for defective pixel detection
AssigneeNVIDIA Corporation
InventorShang-Hung Lin
Life of this patent
Estimating the term…
Abstract
In a method of image signal processing, defective pixels are determined on-the-fly in a digital image representation based on a comparison of a pixel under evaluation with its surrounding pixels, with reference to a known resolving capability of a lens-sensor arrangement that captured the digital image representation. In response to the determination of defective pixels, the defective pixels are corrected.
Claims21
A method of image signal processing for a digital imaging device comprising:
- determining, in an electronic system, defective pixels on-the-fly in a digital image representation based on a comparison of a contrast of a pixel under evaluation with a contrast of its surrounding pixels, with reference to a known resolving capability of a lens-sensor arrangement that captured said digital image representation, wherein said determining includes:
- if said pixel under evaluation is in a flat image region, increasing said known resolving capability by a first percentage,
- if said pixel under evaluation is in an edge image region, increasing said known resolving capability by a second percentage greater than said first percentage, and
- if said digital image representation is captured in a low light level condition, decreasing said known resolving capability by a third percentage greater than said second percentage;
- and
- in response to said determination correcting said defective pixels.
3 more elements
An image signal processor device for a digital imaging device comprising:
- a surrounding pixel interpolator for calculating an average value of same colored pixels surrounding a pixel under evaluation in a portion of a digital image representation;
- a pixel evaluator coupled to said surrounding pixel interpolator, said pixel evaluator for determining if said pixel under evaluation is defective based on a comparison of a contrast of said pixel under evaluation with a contrast of its surrounding pixels, with reference to a known resolving capability of a lens-sensor arrangement that captured said digital image representation, if said pixel under evaluation is in a flat image region, said known resolving capability is increased by a first percentage, if said pixel under evaluation is in an edge image region, said known resolving capability is increased by a second percentage greater than said first percentage, and if said digital image representation is captured in a low light level condition, said known resolving capability is decreased by a third percentage greater than said second percentage;
- and
- a pixel replacer coupled to said pixel evaluator, wherein said pixel replacer is configured for replacing each defective pixel with a replacement pixel comprising said average value calculated by said surrounding pixel interpolator, and wherein said pixel replacer is coupled to a memory component.
1 more element
A digital imaging device comprising:
- an optical lens;
- an image sensor coupled to said lens, said image sensor for capturing a digital image representation;
- and
- an image signal processor coupled to said image sensor, said image signal processor comprising:
- a surrounding pixel interpolator for calculating an average value of same colored pixels surrounding a pixel under evaluation in a portion of said digital image representation;
- a pixel evaluator coupled to said surrounding pixel interpolator, said pixel evaluator for determining if said pixel under evaluation is defective based on a comparison of a contrast of said pixel under evaluation with a contrast of its surrounding pixels, with reference to a known resolving capability of a lens-sensor arrangement that captured said digital image representation, if said pixel under evaluation is in a flat image region, said known resolving capability is increased by a first percentage, if said pixel under evaluation is in an edge image region, said known resolving capability is increased by a second percentage greater than said first percentage, and if said digital image representation is captured in a low light level condition, said known resolving capability is decreased by a third percentage greater than said second percentage;
- and
- a pixel replacer coupled to said pixel evaluator, wherein said pixel replacer is configured for replacing each defective pixel with a replacement pixel comprising said average value calculated by said surrounding pixel interpolator.
5 more elements
Dependencies are inferred from the claim text.