Ashvin K George

US Patent:

8121378, Feb 21, 2012

Filed:

Aug 24, 2009

Appl. No.:

12/546178

Inventors:

Ashvin K. George - Champaign IL, US
Yoram Bresler - Urbana IL, US

Assignee:

The Board of Trustees of The University of Illinois - Urbana IL

International Classification:

G06K 9/00
A61B 6/00

US Classification:

382131, 382154, 378 21

Abstract:

Pixel images {circumflex over (f)} are created from projections (q. . . q) by backprojecting selected projections to produce intermediate images (I), and performing digital image coordinate transformations and/or resampling on selected intermediate images. The digital image coordinate transformations are chosen to account for view angles of the constituent projections of the intermediate images and for their Fourier characteristics, so that the intermediate images may be accurately represented by sparse samples. The resulting intermediate images are aggregated into subsets, and this process is repeated in a recursive manner until sufficient projections and intermediate images have been processed and aggregated to form the pixel image {circumflex over (f)}. Digital image coordinate transformation can include rotation, shearing, stretching, contractions. Resampling can include up-sampling, down-sampling, and the like.

US Patent:

20060257010, Nov 16, 2006

Filed:

Sep 9, 2004

Appl. No.:

10/570020

Inventors:

Ashvin George - Champaign IL, US
Yoram Bresler - Urbana IL, US

International Classification:

G06K 9/00

US Classification:

382131000

Abstract:

Pixel images ƒ are created from projections (q. . . q) by backprojecting () selected projections to produce intermediate images (I, m), and performing digital image coordinate transformations () and/or resampling (FIG. ) on selected intermediate images. The digital image coordinate transformations () are chosen to account for view angles of the constituent projections of the intermediate images and for their Fourier characteristics, so that the intermediate images may be accurately represented by sparse samples. The resulting intermediate images are aggregated into subsets (), and this process is repeated in a recursive manner until sufficient projections and intermediate images have been processed and aggregated to form the pixel image ƒ. Digital image coordinate transformation can include rotation (FIG. ), shearing (Fig. IOB, ), stretching, contractions (), etc. Resampling can include up-sampling (), down-sampling (), and the like. Projections (FIG. pθ. . . pθ) can be created from a pixel image (f), by performing digital iamge coordinate transformation () and/or resampling () and/or decimation (FIG. FIG. ) re-projecting the final intermediate image ().