Method and means of correcting for a shift in the center of rota

Details Method and means of correcting for a shift in the center of rota Method and means of correcting for a shift in the center of rota

1986-07-31

1989-03-14

Smith, Jerry

Boots, shoes, and leggings

378901, 364581, 36441321, G06F 1542

Patent

active

048129836

ABSTRACT:
Method and means for determining and compensating for a shift in the center of rotation of a fan beam CT reconstruction apparatus. Known reconstruction algorithms for fan beam computed tomography are based on the assumption that the center of rotation of the source or detector is on the midline of the fan. In certain cases due, for example, to machine inaccuracies, the center of rotation can be shifted from the assumed center, and such shift can cause artifacts in the reconstruction. The present invention provides a procedure for estimating the magnitude of the shift and also accommodates for the shift by applying a series of weighting factors to the projection information which are dependent on the magnitude of the shift. The weighted projections are then processed by the usual convolution operation, and the convolved projection sets back projected using a geometry modified to account for the shift. Efficiencies are achieved in that all projection sets can be weighted and convolved before back projection, and existing back projection hardware or software can be used to map the modified projection sets into the pixelized image space.

REFERENCES:
Michael J. Dennis, "Preprocessing X-Ray Transmission Data in CT Scanning", Optical Scanning, vol. 16, No. 1, pp. 6-10, Jan.-Feb. 1977.
Franklin J. Weinstein, "Formation of Images Using Fan-Beam Scanning and Noncircular Source Motion", J. Opt. Soc. Am., vol. 70, No. 8, pp. 931-935, Aug. 1980.
C. R. Crawford & A. C. Kak, "Multipath Artifacts in Ultrasonic Transmission Tomograph", School of Electrical Engineering, Purdue Univ., Research, TR-EE, 81-43, pp. 146-161, Dec. 1981.
M. F. Kijewski & P. F. Judy, "The Effects of Misregistration of the Projections on Spatial Resolution of CT Scanners", Medical Physics, vol, 10, No. 2, pp. 169-175, Mar./Apr. 1983.

Affiliated with

Also associated with

Rating

Method and means of correcting for a shift in the center of rota does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Method and means of correcting for a shift in the center of rota, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and means of correcting for a shift in the center of rota will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-898417