Accelerated iterative reconstruction

An image reconstruction method, the method comprising:

• determining an objective function of an inner loop nested within an outer loop;
• iteratively processing the inner loop using ordered subsets until the inner loop is determined to be complete, wherein iteratively processing the inner loop comprises:
• applying a preconditioner;
• and
• computing an image update;
• upon completion of a respective inner loop:
• computing an update direction for the respective outer loop;
• computing a step size for the respective outer loop;
• and
• updating an image;
• determining if the image is converged:
• if the image is not converged, proceeding to a next outer loop, determining a next objective function of a next inner loop, and iteratively processing the next inner loop;
• and
• if the image is converged, ending the image reconstruction.

An image processing system for use in iterative reconstruction, comprising:

• a processing component configured to access acquired image data from an imaging device;
• and
• a memory configured to store one or more routines which, when executed by the processor, cause acts to be performed comprising:
• determining an objective function of an inner loop nested within an outer loop;
• iteratively processing the inner loop using ordered subsets until the inner loop is determined to be complete, wherein iteratively processing the inner loop comprises:
• applying a preconditioner;
• and
• computing an image update;
• upon completion of a respective inner loop:
• computing an update direction for the respective outer loop;
• computing a step size for the respective outer loop;
• and
• updating an image;
• determining if the image is converged:
• if the image is not converged, proceeding to a next outer loop, determining a next objective function of a next inner loop, and iteratively processing the next inner loop;
• and
• if the image is converged, ending the image reconstruction.

One or more non-transitory computer-readable media encoding routines which, when executed, cause acts to be performed comprising:

• determining an objective function of an inner loop nested within an outer loop;
• iteratively processing the inner loop using ordered subsets until the inner loop is determined to be complete, wherein iteratively processing the inner loop comprises:
• applying a preconditioner;
• and
• computing an image update;
• upon completion of a respective inner loop:
• computing an update direction for the respective outer loop;
• computing a step size for the respective outer loop;
• and
• updating an image;
• determining if the image is converged;
• if the image is not converged, proceeding to a next outer loop, determining a next objective function of a next inner loop, and iteratively processing the next inner loop;
• and
• if the image is converged, ending the image reconstruction.