Methods and systems for document-image correction
AssigneeSharp Laboratories of America, Inc.
InventorsLawrence Shao-hsien Chen, Richard John Campbell
Life of this patent
Estimating the term…
Abstract
Aspects of the present invention are related to systems and methods for correcting illumination and vignette in a camera-captured document image. A background type may be detected from down-sampled luminance image associated with the camera-captured image, and model parameters may be estimated for a morphologically filtered version of the down-sampled luminance image, wherein the morphological filter may be based on the detected background type. The model parameters may be verified and if deemed acceptable, a rectified image may be formed.
Claims20
A method for removing artifacts from a digital image, said method comprising:
- down-sampling a luminance image associated with a digital image;
- detecting a background type associated with said down-sampled luminance image;
- estimating model parameters associated with a morphologically filtered version of said down-sampled luminance image;
- verifying said estimated model parameters, wherein said verifying comprises:
- calculating a difference between said filtered image and an image generated using said estimated parameters and a document region-of-interest;
- comparing said calculated difference to an acceptance threshold;
- and
- indicating said estimated model parameters are acceptable when said calculated difference meets a first criterion in relation to said acceptance threshold;
- and
- generating a rectified image associated with said luminance image when said verifying indicates said estimated model parameters are acceptable.
A non-transitory computer-readable medium encoded with a computer program code for implementing a method for removing artifacts from a digital image, said method comprising:
- down-sampling a luminance image associated with a digital image;
- detecting a background type associated with said down-sampled luminance image;
- estimating model parameters associated with a morphologically filtered version of said down-sampled luminance image;
- verifying said estimated model parameters, wherein said verifying comprises:
- calculating a difference between said filtered image and an image generated using said estimated parameters and a document region-of-interest;
- comparing said calculated difference to an acceptance threshold;
- and
- indicating said estimated model parameters are acceptable when said calculated difference meets a first criterion in relation to said acceptance threshold;
- and
- generating a rectified image associated with said luminance image when said verifying indicates said estimated model parameters are acceptable.
Dependencies are inferred from the claim text.