Imaging method and device for the computer-assisted evaluation of computer-tomographic measurements by means of direct iterative reconstruction

• US 7,702,180 B2
• Filed: 02/12/2004
• Issued: 04/20/2010
• Est. Priority Date: 02/17/2003
• Status: Expired due to Fees

• Current Assignee: Bam Bundesanstalt Fuer Materialforschung Und -Pruefung
• Original Assignee: Bam Bundesanstalt Fuer Materialforschung Und -Pruefung
• Inventors: Lange, Axel, Hentschel, Manfred Paul
• Primary Examiner(s): Ahmed; Samir A.
• Assistant Examiner(s): Tsai; Tsung-Yin
• Application Number:
  US10/545,727
• Publication Number:
  US 20060233459A1
• Time in Patent Office: 2,259 Days
• Field of Search: 382/276
• US Class Current: 382/276
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/424 Iterative

Abstract

Disclosed are an imaging method and an arrangement for the computer-assisted evaluation of projected object trajectories obtained from a computer-tomographic measurement. According to the inventive method, the trajectories are arranged in a previously known sequence into a projection matrix as traces of the respective voluminous elements, and the following steps are iterated until a sufficient reconstruction quality has been attained; (a) at least one of the traces is selected; (b) a reconstructed element that is true to the original position is formed from each of the selected traces so as to be added to a reconstructed image; (c) the selected traces are removed from the projection matrix.

Claims

1. An imaging method for computer-assisted evaluation of projected object trajectories of volume elements, which are obtained from computer-tomographic measurement, wherein the projected object trajectories are stored in a preknown sequence as tracks of respective volume elements and are arranged into a projection matrix and the following steps are iterated until an adequate reconstruction quality has been achieved, the steps comprising:

storing average values of the tracks representing all elements of the reconstruction matrix into a memory,

selecting one or more tracks according to a magnitude of its weight and the magnitude of its contrast with respect to adjacent tracks,

forming a positionally-true reconstruction element from the selected one or more tracks including the addition to a reconstruction picture, wherein for forming the positionally-true reconstruction elements of the selected one or more tracks its average value is accumulated with a part of its weight and its contrast,

removing the selected one or more tracks from the projection matrix by removing for the selected one or more tracks a portion of the average value of the respective track from the projection matrix, and

continuing the iteration on the basis of the thus changed projection matrix.

2. A method according to claim 1, wherein the attainment of an adequate reconstruction quality is effected by determining at least one of the intensity and a fluctuation of the projection matrix.

3. A method according claim 1, wherein after the selection of the one or more tracks, its temporal average value is formed along this track.

4. A method according to claim 1, wherein in each iteration, the number of tracks to be selected is selected in dependence on the progress of the reconstruction quality of a preceeding iteration.

5. A method according to claim 1, wherein the portion of the average value of the respective track is selected from the projection matrix and is selected in dependence on the progress of the reconstruction quality of at least one preceeding iteration.