Correction of defective pixels in a detector
AssigneeGE Medical Systems Global Technology Company, LLC
InventorsRichard Aufrichtig, Ping Xue, Kenneth Scott Kump
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Abstract
A detector imaging system having an apparatus and method for correcting defective pixels in an acquired image is disclosed herein. The system includes a correction scheme including temporarily replacing a defective pixel with a linear interpolation of the defective pixel's surrounding neighboring pixel values, determining a local gradient based in part on the acquired image and a gradient kernel, and providing a correction value based on the local gradient to correct the defective pixel. The correction scheme is repeated a plurality of times as desired to correct all the defective pixels in the acquired image.
Claims65
A method for correcting a defective pixel in an image produced by a detector, the image including an array of pixels and the array of pixels having a corresponding array of pixel values, comprising:
- (a) determining a local gradient, the local gradient comprising a plurality of local gradient matrix elements;
- and
- (b) providing a correction value based on the local gradient to correct the defective pixel;
- wherein step (b) of providing a correction value includes at least one of a linear interpolation and a weighted average of pixel values corresponding to pixels selected based on a determination that they had the highest local gradient.
A method for correcting a defective pixel in an image produced by a detector, the image including an array of pixels and the array of pixels having a corresponding array of pixel values, comprising:
- (a) determining a local gradient, the local gradient comprising a plurality of local gradient matrix elements;
- (b) providing a correction value based on the local gradient to correct the defective pixel identifying the defective pixel in the image produced by the detector before the determining step (a);
- replacing the defective pixel with a temporary value based on a linear interpolation of a surrounding neighboring pixels of the defective pixel before the determining step (a) such that determining the local gradient comprises determining the local gradient using the temporary value of the defective pixel;
- and
- replacing the defective pixel with the correction value after the providing step (b).
A system for correcting a defective pixel in an image produced by a detector, comprising:
- a processor coupled to the detector, the processor configured to determine a local gradient and to generate a correction value based on the local gradient, wherein the image includes an array of pixels, each pixel having a corresponding pixel value, and the local gradient comprising an array of local gradient matrix elements;
- wherein the at least a portion of the array of pixel values comprises a matrix, and includes the defective pixel as a center matrix element and each surrounding neighboring pixel of the defective pixel as additional matrix elements;
- and
- wherein the correction value comprises at least one of a linear interpolation and a weighted average of pixel values corresponding to pixels selected based on a determination that they had the highest local gradient.
A system for correcting a defective pixel in an image produced by a detector, the image including an array of pixels, the array of pixels having a corresponding array of pixel values, comprising:
- (a) means for determining a local gradient, the local gradient comprising an array of local gradient matrix elements;
- and
- (b) means for providing a correction value based on the local gradient to correct the defective pixel.
A method for correcting a defective pixel in an image produced by a digital x-ray detector, the image including an array of pixels and the array of pixels having a corresponding array of pixel values, the method comprising:
- acquiring an image from the digital x-ray detector;
- identifying the defective pixel in the image produced by the detector before determining a local gradient;
- determining a local gradient, the local gradient comprising an array of local gradient matrix elements;
- temporarily replacing the defective pixel with a temporary value based on a linear interpolation of a surrounding neighboring pixels of the defective pixel before determining a local gradient such that determining the local gradient comprises determining the local gradient using the temporary value of the defective pixel;
- providing a correction value, which is based on the local gradient, to correct the defective pixel;
- and
- replacing the defective pixel with the correction value;
- wherein the at least a portion of the array of pixel values comprises a matrix, and includes the defective pixel as a center matrix element and each surrounding neighboring pixel of the defective pixel as additional matrix elements.
A method for correcting a defective pixel in an image produced by an x-ray detector having a defective input at the pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- receiving the image from the x-ray detector;
- analyzing global characteristics of pixels in proximity to the defective pixel;
- and correcting the defective pixel based on the global characteristics;
- wherein the pixels in Proximity to the defective pixel whose global characteristics are analyzed include at least a few pixels that are within a three pixel radius of the defective pixel, and that do not border the defective pixel.
A method for correcting a defective pixel in an image produced by a digital detector having a defective input at the defective pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- analyzing a characteristic of each of a plurality of pixels;
- selecting a first pixel of the plurality of pixels having a first pixel value based on the analyzed characteristic of the first pixel;
- selecting a second pixel of the plurality of pixels having a second pixel value based on the analyzed characteristic of the second pixel;
- selecting a third pixel of the plurality of pixels having a third pixel value based on the analyzed characteristic of the third pixel;
- and
- providing a pixel value for the defective pixel using the first second, and third pixel values;
- wherein the analyzed characteristic comprises a gradient of the pixel being analyzed;
- and
- wherein determining the gradient for each pixel includes temporarily replacing the pixel value of the defective pixel with a calculated pixel value;
- wherein the first pixel, the second pixel, and the third pixel selected may be different for each image.
A method for correcting a defective pixel in an image produced by a digital detector having a defective input at the defective pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- analyzing a characteristic of each of a plurality of pixel, the characteristic comprising a gradient;
- selecting a first pixel of the plurality of pixels having a first pixel value based on the analyzed characteristic of the first pixel;
- selecting a second pixel of the plurality of pixels having a second pixel value based on the analyzed characteristic of the second pixel;
- selecting a third pixel of the plurality of pixels having a third pixel value based on the analyzed characteristic of the third pixel;
- and
- providing a pixel value for the defective pixel using the first, second, and third pixel values;
- wherein the gradient for each pixel is determined by
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- where A1 is a matrix of pixel values comprising the image and H is a gradient kernel matrix.
A method for correcting a defective Pixel in an image produced by a detector having a defective input pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- receiving an image from the detector;
- and
- selecting which values to use to provide a value for the defective pixel for the image based on a characteristic of the image, the characteristic of the image comprising gradient values of a plurality of pixels in the image, the plurality of pixels neighboring the defective pixel;
- and
- providing the value for the defective pixel for the image;
- wherein providing the value for the defective pixel for the image includes at least one of a linear interpolation and a weighted average of pixel values corresponding to pixels selected based on a determination that they had highest local gradients of the gradient values of the plurality of pixels in the image neighboring the defective pixel.
A method for correcting a defective pixel in an image produced by a detector having a defective input pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- receiving an image from the detector;
- and
- selecting which values to use to provide a value for the defective pixel for the image based on a characteristic of the image, the characteristic of the image comprising gradient values of a plurality of pixels in the image, the plurality of pixels neighboring the defective pixel;
- wherein the gradient values of the plurality of pixels in the image neighboring the defective pixel are determined by a process comprising replacing the defective pixel with a temporary value, the temporary value based on values of neighboring pixels of the defective pixel.
A method for correcting a defective pixel in an image produced by an x-ray detector having a detective input pixel, the image including an array of pixels and the pixels having corresponding pixel values, the method comprising:
- receiving an image from the x-ray detector;
- and
- selecting which values to use to provide a value for the defective pixel for the image based on a characteristic of the image, comprising,
- analyzing a characteristic of each of a plurality of pixels, the characteristic for each of the plurality of pixels comprising a gradient of the plurality of pixels;
- selecting a first pixel of the plurality of pixels having a first pixel value based on the analyzed characteristic of the first pixel;
- selecting a second pixel of the plurality of pixels having a second pixel value based on the analyzed characteristic of the second pixel:
- and
- providing a pixel value for the defective pixel for the first image using the first and second pixel values;
- wherein the gradient for the first and second pixels are determined by applying
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- where Ai is a matrix of pixel values comprising the image and H is a gradient kernel matrix.
Dependencies are inferred from the claim text.