| 摘要 |
Disclosed herein are embodiments of a rotate-and-slant projector that takes advantage of symmetries in the geometry to compute truly volumetric projections to multiple oblique sinograms in a computationally efficient manner. It is based upon the 2D rotation-based projector using the fast three-pass method of shears, and it conserves the 2D rotator computations for multiple projections to each oblique sinogram set. The projector is equally applicable to both conventional evenly-spaced projections and unevenly-spaced line-of-response (LOR) data (where the arc correction is modeled within the projector). The LOR-based version models the exact location of the direct and oblique LORs, and provides an ordinary Poisson reconstruction framework. Speed optimizations of various embodiments of the projector include advantageously utilizing data symmetries such as the vertical symmetry of the oblique projection process, a coarse-depth compression, and array indexing schemes which maximize serial memory access.
|
