Method and apparatus for automatically locating a region of interest in a radiograph
First Claim
1. A method for automatically locating a desired region of interest (ROI) in an original digital image having a plurality of pixel intensity values, comprising:
- (a) obtaining digital image intensity data representative of an original digital image;
(b) forming a histogram using said image intensity data, wherein one axis of said histogram indicates image intensity value and an orthogonal axis of said histogram indicates image pixel count;
(c) determining a threshold image intensity value from said histogram as being representative of a minimum image intensity value that can possibly be from a desired ROI by;
(c1) determining a point in said histogram representative of a noise peak in said image intensity data; and
(c2) processing said histogram so as to find as said threshold intensity value that image intensity value wherein a portion of said processed histogram that follows said noise peak first exhibits a change to a positive curvature;
(d) creating a mask image from said original digital image, said mask image having image pixels at grid coordinate positions corresponding to similarly positioned pixels in said original digital image, by setting all image pixels in the mask image grid to one of at least a maximum and a minimum intensity value, depending upon a comparison of the threshold intensity value to the image intensity value of the similarly positioned pixel in the original digital image; and
(e) processing said mask image so as to define at least one contiguous area of pixels in said mask image having a common intensity value, said at least one area comprising the desired ROI.
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Accused Products
Abstract
A method for automatically locating a desired region of interest (ROI) in an original digital image involving the use of histograms to determine a threshold that is used to generate a mask to detect the ROIs. Digital image intensity data is obtained and a histogram of the intensity data is formed. The threshold is determined by first determining a histogram point that represents the noise peak in the image intensity data and then setting the threshold to be the image intensity value following the noise peak that first exhibits a positive curvature. The threshold is used to create a mask from the original digital image, and contiguous areas of pixels are defined in the mask. At least one of these contiguous areas is determined to be a desired ROI.
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Citations
26 Claims
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1. A method for automatically locating a desired region of interest (ROI) in an original digital image having a plurality of pixel intensity values, comprising:
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(a) obtaining digital image intensity data representative of an original digital image; (b) forming a histogram using said image intensity data, wherein one axis of said histogram indicates image intensity value and an orthogonal axis of said histogram indicates image pixel count; (c) determining a threshold image intensity value from said histogram as being representative of a minimum image intensity value that can possibly be from a desired ROI by; (c1) determining a point in said histogram representative of a noise peak in said image intensity data; and (c2) processing said histogram so as to find as said threshold intensity value that image intensity value wherein a portion of said processed histogram that follows said noise peak first exhibits a change to a positive curvature; (d) creating a mask image from said original digital image, said mask image having image pixels at grid coordinate positions corresponding to similarly positioned pixels in said original digital image, by setting all image pixels in the mask image grid to one of at least a maximum and a minimum intensity value, depending upon a comparison of the threshold intensity value to the image intensity value of the similarly positioned pixel in the original digital image; and (e) processing said mask image so as to define at least one contiguous area of pixels in said mask image having a common intensity value, said at least one area comprising the desired ROI. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. Apparatus for automatically locating a desired region of interest (ROI) in an original digital image having a plurality of pixel intensity values, comprising:
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(a) means for obtaining digital image intensity data representative of an original digital image; (b) means for forming a histogram using said image intensity data, wherein one axis of said histogram indicates image intensity value and an orthogonal axis of said histogram indicates image pixel count; (c) means for determining a threshold image intensity value from said histogram as being representative of a minimum image intensity value that can possibly be from a desired ROI by; (c1) determining a point in said histogram representative of a noise peak in said image intensity data; and (c2) processing said histogram so as to find as said threshold intensity value that image intensity value wherein a portion of said processed histogram that follows said noise peak first exhibits a change to a positive curvature; (d) means for creating a mask image from said original digital image, said mask image having image pixels at grid coordinate positions corresponding to similarly positioned pixels in said original digital image, by setting all image pixels in the mask image grid to one of at least a maximum and a minimum intensity value, depending upon a comparison of the threshold intensity value to the image intensity value of the similarly positioned pixel in the original digital image; and (e) means for processing said mask image so as to define at least one contiguous area of pixels in said mask image having a common intensity value, said at least one area comprising the desired ROI. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. Apparatus for automatically locating a desired region of interest (ROI) in an original digital image having a plurality of pixel intensity values, comprising:
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(a) means for obtaining digital image intensity data representative of an original digital image; (b) means for compressing said digital image intensity data; (c) means for sampling the digital image intensity data of said original digital image so as to create a reduced digital image representative of said original digital image, said reduced digital image comprising a sub-set of the digital image intensity data of the original digital image; (d) means for forming a histogram using said sub-set of image intensity data, wherein one axis of said histogram indicates increasing image intensity value and an orthogonal axis of said histogram indicates increasing image pixel count; (e) means for determining a threshold image intensity value from said histogram as being representative of a minimum image intensity value that can possibly be from a desired ROI by; (e1) determining a point in said histogram representative of a noise peak in said image intensity data; and (e2) processing said histogram so as to find as said threshold intensity value that image intensity value wherein a portion of said processed histogram that follows said noise peak first exhibits a change to a positive curvature; and (f) means for creating a mask image from said sub-set of digital image intensity data, said mask image having image pixels at grid coordinate positions corresponding to similarly positioned pixels in said original digital image that were sampled for forming said reduced digital image, by setting all image pixels in a mask image grid to one of at least a maximum and a minimum intensity value, depending upon a comparison of the threshold intensity value to the image intensity value of a correspondingly positioned pixel in the reduced digital image, thereby defining at least one contiguous area of pixels in said mask image having a common intensity value, said at least one area comprising the desired ROI.
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Specification