Automatic image segmentation methods and analysis
The invention provides methods and apparatus for image processing that perform image segmentation on data sets in two- and/or three-dimensions so as to resolve structures that have the same or similar grey values (and that would otherwise render with the same or similar intensity values) and that, thereby, facilitate visualization and processing of those data sets.
1. A method of processing anatomical structures present in a two-dimensional (2D) image slice using a digital data processor that labels connected components comprising:
(a) selecting a 2D image slice from a plurality of first 2D image slices spanning a three dimensional (3D) volume, using a digital data processing system configured for image processing, where each of the pixels of the selected 2D image slice have one or more of a first intensity value, a second intensity value and a third intensity value, where the second intensity value is greater than the first intensity value, where the third intensity value is greater than the second intensity value;
(b) computing with a digital data processing system a histogram of the 2D image slice;
(c) comparing the histogram of step (b) with an anatomic atlas of average histograms including computing with a digital data processing system a correlation between the histogram and the anatomic atlas of average histograms;
(d) identifying with a digital data processing system one or more pixels corresponding with a first structure of interest in the 2D image slice based on the comparison of step (c);
(e) assigning with a digital data processing system the one or more pixels identified in step (d) to one or more seed points, where the one or more pixels have an intensity value above the first intensity value or above the second intensity value;
(f) flood filling with a digital data processing system from the one or more seed points to one or more pixels connected to one of the one or more seed points to identify the first structure of interest; and
(g) labeling with a digital data processing system the first structure of interest on the selected 2D image slice.
2. The method of claim 1 , where step (e) continues until at least one of the one or more pixels ‘stair-steps’ an identified pixel, where the identified pixel does not correspond with the first structure of interest based on the identification in step (d).
3. The method of claim 1 , where the flood filling in step (f) continues where the one or more pixels connected to one or more seed points have an intensity value above the first intensity value.
4. The method of claim 1 , where a first structure of interest is resolved from a pixel not assigned to the first structure of interest based on assigning pixels at or above the first intensity value in step (f).
5. The method of claim 1 , where a first structure of interest is resolved from a pixel not assigned to the first structure of interest identified based on assigning pixels at or above the second intensity value in step (f).
6. The method of claim 1 , where step (c) includes the step of computing a cross correlation between the histogram of step (b) and the anatomic atlas of average histograms.
7. The method of claim 1 , where a first structure of interest is selected from the group consisting of a bone structure and a vessel structure.
8. The method of claim 1 , where a first structure corresponding to a bone structure is removed from the labeled 2D image slice.
9. The method of claim 1 , where a first structure corresponding to a vessel structure is displayed in the labeled 2D image slice.
10. The method of claim 1 , further comprising where pixels not assigned to the first structure of interest are automatically removed from the labeled 2D image.
11. A method of processing anatomical structures present in a two-dimensional (2D) image slice using a digital data processor that identifies using color connected components comprising:
(a) selecting a 2D image slice from a plurality of first 2D image slices spanning a three dimensional (3D) volume, using a digital data processing system configured for image processing, where each of the pixels of the selected 2D image slice have one or more of a first intensity value, and a second intensity value, where the second intensity value is greater than the first intensity value;
(b) computing with a digital data processing system a histogram of the 2D image slice;
(c) comparing the histogram of step (b) with an anatomic atlas of average histograms including computing with a digital data processing system a correlation between the histogram and the anatomic atlas of average histograms;
(d) identifying with a digital data processing system one or more pixels corresponding with a first structure of interest in the 2D image slice based on the comparison of step (c);
(e) assigning with a digital data processing system the one or more pixels identified in step (d) to one or more seed points, where the one or more pixels have an intensity value above a first intensity value;
(f) flood filling with a digital data processing system from the one or more seed points to one or more pixels connected to one of the one or more seed points to identify the first structure of interest; and
(g) coloring with a digital data processing system the first structure of interest on the selected 2D image slice.
12. The method of claim 11 , where a first structure of interest is selected from the group consisting of a bone structure and a vessel structure.
13. The method of claim 11 , where a first structure corresponding to a bone structure is removed from the colored 2D image slice.
14. The method of claim 11 , where a first structure corresponding to a vessel structure is displayed in the colored 2D image slice.
15. The method of claim 11 , further comprising where pixels not assigned to the first structure of interest are automatically removed from the colored 2D image.
16. The method of claim 11 , where step (e) is repeated with the second intensity value.
17. The method of claim 11 , where the first structure of interest is a bone structure, where a second structure of interest corresponding with a vessel structure is colored with another color.
18. A method of processing anatomical structures present in a two-dimensional (2D) image slice using a digital data processor that identifies connected components comprising:
(a) selecting a 2D image slice from a plurality of first 2D image slices spanning a three dimensional (3D) volume, using a digital data processing system configured for image processing, where each of the pixels of the selected 2D image slice have one or more of a first intensity value, a second intensity value and a third intensity value, where the second intensity value is greater than the first intensity value, where the third intensity value is greater than the second intensity value;
(b) computing with a digital data processing system a histogram of the 2D image slice;
(c) comparing the histogram of step (b) with an anatomic atlas of average histograms including computing with a digital data processing system a correlation between the histogram and the anatomic atlas of average histograms;
(d) using a digital data processing system to assign one or more seed points above the first intensity value in a first structure of interest in the 2D image slice based on the comparison of step (c);
(e) flood filling with a digital data processing system from the one or more seed points to one or more pixels connected to one of the one or more seed points to identify the first structure of interest; and
(f) coloring with a digital data processing system the first structure of interest on the selected 2D image slice.
19. The method of claim 18 , where step (d) is repeated with the second intensity value.
20. The method of claim 18 , where the first structure of interest is a bone structure, where a second structure of interest corresponding with a vessel structure is identified.