CT dose reduction filter with a computationally efficient implementation
First Claim
1. A method for reducing noise in a discrete pixel image, the method comprising the steps of:
- (a) shrinking an initial image by a given factor to produce a shrunken image;
(b) reducing image noise by selectively processing one or more selected regions of the shrunken image and differentially processing one or more non-selected regions of the shrunken image such that a processed image results;
(c) expanding the processed image by the given factor to produce an expanded image;
(d) blending one or more selected regions of the expanded image with one or more corresponding regions of the initial image to produce a blended image; and
(e) correcting a plurality of intensity values of the blended image by differentially processing two or more regions.
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Abstract
A technique for reducing noise in pixel images includes modifying initial image data to prevent subsequent image data loss, shrinking the modified image, processing the shrunken image with known segmentation-based filtering techniques which identify and differentially processing structures within the image. After processing, the shrunken image is enlarged to the dimensions of the initial data and subsequently processed to correct intensity irregularities and to preserve CT numbers. The resulting technique is versatile and provides greatly improved computational efficiency while maintaining image quality, allowing for dose reduction during imaging.
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Citations
94 Claims
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1. A method for reducing noise in a discrete pixel image, the method comprising the steps of:
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(a) shrinking an initial image by a given factor to produce a shrunken image;
(b) reducing image noise by selectively processing one or more selected regions of the shrunken image and differentially processing one or more non-selected regions of the shrunken image such that a processed image results;
(c) expanding the processed image by the given factor to produce an expanded image;
(d) blending one or more selected regions of the expanded image with one or more corresponding regions of the initial image to produce a blended image; and
(e) correcting a plurality of intensity values of the blended image by differentially processing two or more regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for reducing noise in a discrete pixel image, the method comprising the steps of:
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(a) sub-sampling an initial image containing image data representative of pixels of a reconstructed image such that a shrunken image results and such that the initial image is shrunk by a factor greater than one;
(b) identifying one or more structural features from the image data represented in the shrunken image;
(c) smoothing the structural features to enhance a dominant orientation of the structural features;
(d) smoothing non-structural region to enhance a homogenization of the non-structural region;
(e) sharpening the structural features to enhance the dominant orientation associated with the structural features;
(f) expanding the shrunken image by the factor such that an expanded image results which has the same dimensions as the initial image;
(g) blending a fraction of the expanded image with image data from the first initial image to form a blended image; and
(h) correcting intensity values of the blended image by identifying two or more regions within the blended image and modifying each region differentially to form a corrected image. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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52. A system for reducing noise in a discrete pixel image, the system comprising:
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an output device for producing a reconstructed image based upon processed image data; and
a signal processing circuit configured to provide processed image data by sub-sampling an initial image to produce a shrunken image, identifying one or more selected regions of the shrunken image using one or more selection criteria, differentially processing the selected regions and one or more non-selected regions to create a processed image, expanding the processed image to the same dimensions as the initial image, blending a fraction of the expanded image data with the initial image data, and differentially correcting intensity values in two or more regions of the blended image using an image mask. - View Dependent Claims (53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A system for reducing noise in a discrete pixel image, the system comprising:
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an output device for producing a reconstructed image based upon processed image data; and
a signal processing circuit configured to provide processed image data by sub-sampling an initial image to produce a shrunken image, smoothing image data representative of pixels of the shrunken image, identifying one or more structural features from the smoothed image data, orientation smoothing the structural features, homogenization smoothing non-structural regions, orientation sharpening the structural features, expanding the shrunken image to the same dimensions as the initial image to form an expanded image, blending of the initial image data into the expanded image data, and differentially correcting intensity values in two or more regions of the blended image using an image mask. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94)
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Specification