Automated image detail localization method

Claims

What is claimed is:

1. A method for analyzing a cross-sectional digitized image of the internal structure of a body having digitized image pixels with intensities that vary in accordance with the physical characteristics of the body, said digitized image being provided by a medical imaging system, so as to measure the physical characteristics of a particular portion of the body structure, comprising the steps of:

(a) positioning a calibration phantom proximate to the body so that a representation of a cross-section of said calibration phantom is included as part of said digitized image, said calibration phantom having at least first and second calibration portions, each having known, calibrated physical characteristics, said digitized image further including first and second calibration portion images, each having a respective intensity corresponding to the physical characteristics of said first and second calibration portions, respectively;

(b) automatically comparing the intensities of the digitized image pixels on a first axis with a predetermined range of intensities corresponding to the intensity of said first calibration portion image to locate image pixels having intensities within said predetermined range of intensities;

(c) automatically geometrically locating a first center pixel on said first axis;

(d) automatically comparing the intensities of the digitized image pixels on a second axis with a predetermined range of intensities corresponding to the intensity of said first calibration portion image to locate image pixels having intensities within said predetermined range of intensities;

(e) automatically geometrically locating a second center pixel of said second axis;

(f) repeating steps (b)-(e) a selected number of times using said first and second axes so as to automatically locate the center of said first calibration portion image;

(g) automatically defining a region of interest centered on said center of said first calibration portion image upon location of said center of said first calibration image;

(h) calculating an intensity representative of the pixels within the region of interest of said first calibration portion image;

(i) repeating steps (b)-(h) for said second calibration portion image to automatically locate the center of said second calibration image, to automatically define a region of interest centered on said center of said second calibration portion image, and to calculate an intensity representative of the pixels within the region of interest of said second calibration portion image;

(j) calculating a calibration factor that relates the intensity of the pixels representative of said first and second calibration portion images with the known, calibrated physical characteristics of said first and second calibration portions of said calibration phantom;

(k) calculating an intensity representative of an image of a portion of said body structure; and

(1) applying said calibration factor to said calculated intensity of said image of said portion of said body structure to calculate the physical characteristics of said body portion.

2. The method as defined in claim 1, wherein said steps (b)-(e) are performed using the horizontal axis as the first axis and the vertical axis as the second axis.

3. A method for analyzing a cross-sectional digitized image of the internal of a body having digitized image pixels with intensities that vary in accordance with the physical characteristics of the body, said digitized image being provided by a medical imaging system, so as to measure the physical characteristics of a particular portion of the body structure, comprising the steps of:

positioning a calibration phantom proximate to the body so that a representation of a cross-section of said calibration phantom is included as part of said digitized image, said calibration phantom having at least first and second calibration portions, each having known, calibrated physical characteristics, said digitized image further including at least first and second calibration portion images, each having an intensity corresponding to the physical characteristics of said first and second calibration portions, respectively;

for each of said first and second calibration portion images, automatically comparing the intensities of the digitized image pixels with a respective predetermined range of intensities corresponding to the respective intensity of said calibration portion image to locate image pixels having intensities within said respective predetermined range of intensities, said step of automatically comparing the intensities of said digitized image pixels comprising the steps of:

finding a first digitized image pixel having an intensity within said respective predetermined range of intensities;

comparing the intensities of digitized image pixels proximate to said first digitized image pixel with said respective predetermined range of intensities;

counting the number of said proximate image pixels having intensities within said respective predetermined range of intensities; and

comparing said number of said proximate image pixels to a predetermined number and selecting one of said proximate image pixels as a starting location;

automatically locating a respective center of each of said first and second calibration portion images using said starting location selected for each of said first and second calibration portion images;

automatically defining first and second regions of interest centered on said centers of said first and second calibration portion images, respectively;

calculating intensities representative of the pixels within the regions of intensity of said first and second calibration portion images;

calculating a calibration factor that relates the intensities of the pixels representative of said first and second calibration portion images with the known, calibrated physical characteristics of said first and second calibration portions of said calibration phantom;

calculating an average intensity representative of an image of a portion of said body structure; and

applying said calibration factor to said calculated average intensity of said image of said portion of said body structure to calculate the physical characteristics of said body portion.

4. The method as defined in claim 3 wherein for each of said first and second calibration portion images, said step of automatically locating said respective center of said calibration portion image comprises the steps of:

starting with said selected proximate image pixel and comparing the intensities of image pixels in the same row on a first axis to the left and to the right of said selected proximate image pixel with said respective predetermined range of intensities and selecting the leftmost and rightmost pixels having intensities within said respective predetermined range of intensities;

selecting an image pixel substantially equidistant from said selected leftmost and said selected rightmost image pixels as a first selected center pixel;

comparing image pixels in the same column on a second axis as said first selected center pixel with said respective predetermined range of intensities and selecting the uppermost and lowermost image pixels in said column having intensities within said respective predetermined range of intensities; and

selecting an image pixel substantially equidistant from said selected uppermost and said selected lowermost image pixels as a second selected center pixel, said second selected center pixel substantially corresponding to said respective center of said calibration portion image.

5. The method as defined in claim 4, further including the steps of:

starting with said second selected center pixel and comparing the intensities of image pixels in the same row on said first axis to the left and to the right of said second selected center pixel with said predetermined range of intensities and selecting the leftmost and rightmost pixels having intensities within said predetermined range of intensities;

selecting an image pixel substantially equidistant from said selected leftmost and said selected rightmost image pixels as a third selected center pixel;

comparing image pixels in the same column on said second axis as said third selected center pixel with said predetermined range of intensities and selected the uppermost and lowermost image pixels in said column having intensities within said predetermined range of intensities; and

selecting an image pixel substantially equidistant from said selected uppermost and said selected lowermost image pixels as a fourth selected center pixel, said fourth selected center pixels substantially corresponding to said center of said calibration portion image.

6. A method for analyzing a digitized image of a portion of the internal structure of a body positioned within an imaging field of an imaging system, said image having intensities that vary in accordance with the physical characteristics of the body and that vary in accordance with variations in the operational characteristics of said imaging system, said method being designed so as to measure the intensities of said digitized image and provide calibrated quantitative information regarding said physical characteristics of said body represented by said digitized image, said method comprising the steps of:

providing an object of known physical characteristics within said imaging field so that said digitized image includes at least first and second digitized representations of said known physical characteristics of said object;

locating on said digitized image first and second calibration regions positioned totally within said first and second digitized representations of said known physical characteristics of said object, said locating step for each of said first and second calibration regions comprising the steps of:

automatically comparing the intensities of discrete portions of said digitized image with a range of intensities corresponding to said known physical characteristics of said object for said calibration region; and

selecting a plurality of said discrete portions having intensities within said range of intensities to comprise said calibration region;

calculating a respective intensity representative of said plurality of discrete portions of each of said first and second calibration regions;

generating a calibration factor that relates said intensities representative of said plurality of discrete portions of said first and second calibration regions to said known physical characteristics of said object; and

applying said calibration factor to said measured intensities of