Optimizing the acquisition time profile for a planar integral measurement system with a spinning slat collimator.
This article considers a hypothetical imaging device with a spinning slat collimator that measures parallel-planar-integral data from an object. This device rotates around the object 180 degrees and stops at N positions uniformly distributed over this 180 degrees. At each stop, the device spins on its own axis 180 degrees and acquires measurements at M positions uniformly distributed over this 180 degrees. For a fixed total imaging time, an optimal distribution of the scanning time among the data measurement locations is searched by a nonlinear programming method: Nelder-Mead's simplex method. The optimal dwell time is approximately proportional to the weighting factor in the backprojector of the reconstruction algorithm. By using an optimal dwell-time profile, the reconstruction signal-to-noise ratio has a gain of 23%-24% for the filtered backprojection algorithm and a gain of 10%-18% for the iterative algorithms, compared with the situation when a constant dwell-time profile is used.
Earl
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RD
Fidelity Investments, 201 South Main Street, Salt Lake City, Utah 84111, USA.
Zeng
G L
GL
Zhang
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B
D000465:Algorithms; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*