US006771732B2 (12) United States Patent (10) Patent N0.: US 6,771,732 B2 Xiao et al. (45) Date of Patent: Aug. 3, 2004 (54) METHODS AND APPARATUS FOR FAST “Fast Calculation of Multiple Line Integrals”; Brandt et al; DIVERGENT BEAM TOMOGRAPHY SIAMJ. Sci. Comput, vol. 20, No. 4, pp. 1417—1429; 1999. Multi—Resolution Mixed Radix Quadtree SAR Image (75) Inventors: Shu Xiao, Sunnyvale, CA (US); Yoram Focusing Algorithms; Oh et al; Third Annual Federated Bresler, Urbana, IL (US); David C. Laboratory Symposium on Advanced Sensors; pp. 139—143; Munson, J r., Champaign, IL (US) Feb. 2—4, 1999. “Iterative Techniques for Projection and Back—Projection”; (73) Assignee: The Board of Trustees of the Per—Erik Danielsson; Institute of Technology, Linkopings University of Illinois, Urbana, IL (US) Universilet; pp. 1—39; Jun. 1997. ( * ) Notice: Subject to any disclaimer, the term of this “Three—dimensional Reconstruction from Cone—beam Data patent is extended or adjusted under 35 in O(N3log N)Time”; Axelsson et al.; Phys. Med. Biol.; 39, U.S.C. 154(b) by 64 days. pp. 477—491; 1994. “A Fast Discrete Approximation Algorithm for the Radon (21) Appl. No.: 10/190,295 Transform”; Martin Brady; SIAM J. Comput, vol. 27, No. 1, pp. 107—119; Feb. 1998. (22) Filed: Jul. 5, 2002 (65) Prior Publication Data (List continued on next page.) US 2003/0161443 A1 Aug. 28, 2003 Primary Examiner—David Bruce (74) Attorney, Agent, or Firm—Greer, Burns & Crain, Ltd. Related US. Application Data (60) Provisional application No. 60/360,390, ?led on Feb. 28, (57) ABSTRACT 2002. A fast method for divergent-beam backprojection is pro posed for generating an electronic image from a prepro (51) Int. Cl.7 ................................................ .. A61B 6/03 cessed divergent-beam sonogram, the sinogram being a collection of divergent beam projections. The method con (52) US. Cl. ............................ .. 378/4; 378/15; 378/901 sists of the following steps: subdividing the sinogram into multiple sub-sinograms; performing a Weighted backprojec (58) Field of Search ............................. .. 378/4, 15, 901 tion of said sub-sinograms, to produce multiple correspond (56) References Cited ing sub-images; and aggregating said sub-images to create the electronic image. The subdivision of the sinogram into U.S. PATENT DOCUMENTS sub-sinograms can be performed in a recursive manner. A 5,778,038 A 7/1998 Brandt et a1. ................ .. 378/4 dual of the proposed method provides a fast means for 5,805,098 A 9/1998 McCorkle .................. .. 342/25 reprojecting an electronic image, i.e., generating a divergent-beam sinogram from the image. These methods 6,151,377 A 11/2000 Nilsson . . . . . . . . . . .. 378/4 6,263,096 B1 * 7/2001 Boag et al. .. .. 382/128 are applicable to fan-beam and cone-beam tomography 6,282,257 B1 * 8/2001 Basu et al. 378/15 utilizing a variety of scanning trajectories, including spiral. 6,307,911 B1 * 10/2001 Basu et al. ................. .. 378/15 These methods do not require rebinning, and offer speedups 6,332,035 B1 * 12/2001 Basu et al. ............... .. 382/128 similar to the FFT When compared to conventional back 6,351,548 B1 * 2/2002 Basu et al. ............... .. 382/128 projection and reprojection algorithms. Substantial compu OTHER PUBLICATIONS tational savings are obtained Without perceptible degrada “Cone—Beam Reconstruction Using Filtered Backprojec tion or signi?cant loss of numerical accuracy. tion”; Henrik Turbell; Institute of Technology, Linkopings Universitet; pp. 1—169; Feb. 2001. 44 Claims, 35 Drawing Sheets D5 SEVUGRAM (UR SL'BSINOGRLVD WITH P PROIECITONS DB SWWOIGTRHA LMQ‘ PURROSIUEBCSITIONNOSG RAM DB SUB-SINDGRAM WITH P/L PROIECHONS US 6,771,732 B2 Page 2 OTHER PUBLICATIONS “Error Analysis and Perforarnnce Optimization of Fast Hier archical Backprojection Algorithrns”; Basu et al; ; IEEE “Fast Feldkarnp Reconstruction”; Turbell, et al,; Linkopings Transactions on Image Processing; vol. 10, No. 7; pp. Universitel; Dec. 15, 1998. 1103—1117; Jul. 2001. “The PI—FAST Method for Approximate Helical Cone—bearn Reconstruction”; Turbell et al.; Proc. Sixth Int. “O(N3log N) Backprojection Algorithm for the 3—D Radon Meeting on Fully Three—Dirnensional Image Reconstruction Transforrn”; Basu et al. .; IEEE Transactions on Medical in Radiology and Nuclear Med.; Asilornar, Paci?c Grove, Imaging; vol. 21, No. 2; pp. 76—88; Feb. 2002. CA; Oct. 30—Nov. 2, 2001. “Multifrequential Algorithm for Fast 3D Reconstruction”; Seger et al.; “Real Time SAR Processing of LoW Frequency Rodet et al.; Proc. Sixth Int. Meeting on Fully Three—Di Ultra Wide Band Radar Data”; European Conference on rnensional Irnage Reconstr. In Radiology and Nuclear Med., Synthetic Aperture Radar; Friedrichshafen, Gerrnany; pp. Asilornar, Paci?c Grove, CA; Oct. 30—Nov. 2, 2001. 489—492; May 1998. “A Multilevel Dornain Decornposition Algorithm for Fast 0(N2 log N ) Reprojection of Tornographic Irnages”; Boag Hellsten et al; Synthetic—Aperture Radar Processing Using et al.; IEEE Transactions on Image Processing; vol. 9, No. Fast Factorised Backprojection; European Conference on 9; pp. 1573—1582; Sep. 2000. Synthetic Aperture Radar; Friedrichshafen, Gerrnany; pp. “O(N2log2N) Filtered Backprojection Reconstruction Algo 753—756; 2000. rithrn for Tornography”;Basu et al.; IEEE Transactions on Image Processing: vol. 9, No. 10:pp. 1760—1773; Oct. 2000. * cited by exarniner U.S. Patent Aug. 3, 2004 Sheet 1 0f35 US 6,771,732 B2 SCANNER $11 14*"; ------- -----»ns PROJECTIONS PROJECTION PREPROCESSOR 7" ‘6 13% ------- ------DB SINOGRAM1 SINOGRAM 2° DB swam/13"" UPDATE _ ~---DB SH‘IOGRAh/IZ PROCESSOR 22 N w 34 v 24'» FAST FAST wag BACKPROIECTION REPROJEC'I'ION PROCESSOR PROCESSOR 28”“ IMAGE 30 ELEC mama! - (IONDHIONLN’G ----ELEC IMAGE; PROCESSOR 36”“, ------- --—--~Euzc IMAGE3 STORAGE! /’ ANALYSIS! M38 10 DISPLAY FIG. 1 U.S. Patent Aug. 3, 2004 Sheet 2 0f35 US 6,771,732 B2 SOURCE ORBIT ' ...... , FIG. 2 U.S. Patent Aug. 3, 2004 Sheet 3 0f35 US 6,771,732 B2 FIG. 3 U.S. Patent Aug. 3, 2004 Sheet 4 0f35 US 6,771,732 B2 FIG. 4 U.S. Patent Aug. 3, 2004 Sheet 5 0f35 US 6,771,732 B2 ,/ F a T(9. F) 5 0 D " EQUALLY SPACED DETECTORS FIG. 5 U.S. Patent Aug. 3, 2004 Sheet 6 0f35 US 6,771,732 B2 FIG. 6 U.S. Patent Aug. 3, 2004 Sheet 7 0f 35 US 6,771,732 B2 t= 116,1‘) FIG. 7 U.S. Patent Aug. 3, 2004 Sheet 8 0f 35 US 6,771,732 B2 Ay 73 B \ m T(e,5) 0 FIG. 8
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