Imaging auto shutter ROI
View Patent ↗A method to identify a Region Of Interest (ROI) within an image includes the steps of: reading a digital image; finding predetermined brightness values; analyzing lines near a plurality of outer edges of the digital image; identifying an entire area of the digital image as the ROI if the found brightness values are also found in lines near the plurality of outer edges of the digital image; computing Radon transforms to generate one dimensional (1D) projections of the digital image if the found brightness values are not found in the lines; detecting a set of edges within the 1D projections; selecting edges from the set of edges; validating the selected edges to identify a set of validated edges; computing the ROI from the set of validated edges of the 1D projections; and saving the computed ROI to memory. A system to perform the method is also described.
1. A method to identify a Region Of Interest (ROI) within an image, said method comprising the steps of:
providing a digital image;
reading said digital image;
finding one or more predetermined brightness values in said digital image;
analyzing one or more lines near a plurality of outer edges of said digital image to test for values statistically close in brightness to said one or more found brightness values;
identifying an entire area of said digital image as said ROI if said found brightness values are also found in said one or more lines near said plurality of outer edges of said digital image;
computing two or more Radon transforms to generate two or more one dimensional (1D) projections of said digital image if said found brightness values are not found in said one or more lines near the outer edges of said digital image;
detecting a set of edges within said two or more 1D projections;
selecting edges from said set of edges;
validating said selected edges to identify a set of validated edges;
computing said ROI from said set of validated edges of said two or more 1D projections; and
saving said computed ROI to memory.
2. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises at least one Radon transform having a projection.
3. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises at least one Radon transform having a maximum projection.
4. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises computing a Radon transform projection of each column and each row of said digital image.
5. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises computing at least one Radon transform having a mean projection.
6. The method of claim 1 , wherein the step of computing two or more Radon transforms further comprises computing a Radon transformation off-axis from each row and column of said digital image.
7. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises computing a Radon transformation having a projection at an angle.
8. The method of claim 1 , wherein the step of computing two or more Radon transforms comprises computing a Radon transformation having horizontal and vertical mean projections.
9. The method of claim 8 , wherein the step of computing two or more Radon transforms comprises computing one or more mean projections.
10. The method of claim 1 , wherein the step of validating said selected edges to identify a set of validated edges further comprises excluding one or more of said selected edges.
11. The method of claim 1 , wherein the step of computing said ROI from said set of validated edges further comprises excluding one or more of said detected edges within a pre-determined region of said digital image.
12. The method of claim 1 , further comprising a step setting starting ROI values to zeros, between said step of reading said digital image and said step of finding one or more predetermined brightness values.
13. The method of claim 12 , wherein if said ROI values are not successfully computed from said validated edges of said two or more ID projections of said digital image, said ROI values are set to final values which include an entire area of said digital image and said digital image is saved to memory in its entirety.
14. The method of claim 1 , wherein said step of saving said computed ROI to memory further comprises setting values of said digital image outside of said ROI, as computed in the step of computing said ROI from said set of edges, to zero or a prespecified value and saving said ROI.
15. An imaging system comprising:
a source of imaging radiation having a shutter configured by one or more adjustable blades;
a detector for detecting an absorbed, transmitted, or projection of said imaging radiation in a plane; and
an imaging computer component communicatively coupled to said detector and configured to run an auto shutter ROI algorithm to find a region of interest (ROI);
wherein said autoshutter ROI algorithm is configured to read a digital image electronically from said detector following a medical image acquisition, find one or more maximum brightness values within said digital image, analyze one or more lines near the outer edges of said digital image to look for values at or near said maximum brightness values, set said ROI to an entire area of said digital image if said maximum brightness values are found in said one or more lines near the outer edges of said digital image indicating that said shutter was substantially fully open during an exposure that created said digital image; and
wherein if said maximum brightness values are not found by using said one or more lines near the outer edges of said digital image indicating that said shutter was not in a substantially fully opened position during an exposure that created said digital image, said autoshutter ROI algorithm configured to calculate two or more Radon transforms to generate two or more 1D projections of said digital image to detect edges in said 1D projections, wherein one or more of said detected edges are selected, and said selected edges are validated to compute said ROI from said detected edges of said two or more ID projections of said digital image, and to save said ROI as computed to memory.
16. The imaging system of claim 15 , wherein said source of imaging radiation comprises an X-ray source.
17. The imaging system of claim 15 , wherein said two or more Radon transforms comprise projections of each column and each row of said digital image.
18. The imaging system of claim 15 , wherein at least one Radon transform comprises a mean projection.
19. The imaging system of claim 15 , wherein said autoshutter ROI algorithm is further configured to calculate at least one Radon transformation off-axis from each row and column of said digital image.
20. The imaging system of 19 , wherein said at least one Radon transformation off-axis from said rows and columns comprises a mean projection.
21. The imaging system of claim 15 , wherein said autoshutter ROI algorithm is further configured to reject one or more computed edges within a pre-determined region of said digital image.
22. The imaging system of claim 15 , wherein said autoshutter ROI algorithm is further configured to set a set of starting ROI values to zeros after said digital image is read.
23. The imaging system of claim 22 , wherein if said ROI values are not successfully computed from said detected edges of said two or more ID projections of said digital image, said ROI values are set to final values which include an entire area of said digital image and said digital image is saved to memory in its entirety.
24. The imaging system of claim 15 , further comprising setting values of said digital image outside of said ROI to zero or a prespecified value and saving the ROI as an extracted image.