Method and apparatus for scatter estimation in computed tomography imaging systems

A method for performing scatter estimation in a computed tomography (CT) system, comprising:

• obtaining projection data by scanning an imaging object using the CT system;
• reconstructing image data from the obtained projection data;
• calculating, based on the obtained projection data and the reconstructed image data, a first scatter distribution, using a physical-process-based model;
• and
• determining, based on the calculated first scatter distribution, a second scatter distribution, where the determined second scatter distribution includes higher order scattered components compared with the calculated first scatter distribution.

An apparatus for performing scatter estimation in a computed tomography (CT) system including a detector having a plurality of detector pixels, the apparatus comprising:

• processing circuitry configured to
• obtain projection data by scanning an imaging object using the CT system;
• reconstruct image data from the obtained projection data;
• estimate, based on the obtained projection data, a first scatter distribution;
• select, based on the estimated first scatter distribution, a first subset of the plurality of detector pixels;
• calculate, based on the obtained projection data and the reconstructed image data, a second scatter distribution with respect to the selected first subset of the plurality of detector pixels, the calculated second scatter distribution having higher accuracy than the estimated first scatter distribution;
• and
• acquire, based on the calculated second scatter distribution, a third scatter distribution with respect to a second subset of the plurality of detector pixels, so that the acquired third scatter distribution has higher spatial resolution than the calculated second scatter distribution, where the second subset includes the first subset,
• wherein the processing circuitry is further configured to select the first subset by down-sampling, based on a predetermined criterion, the plurality of detector pixels to obtain the selected first subset of the plurality of detector pixels, and
• the processing circuitry is further configured to down-sample the plurality of detector pixels by generating the selected first subset of the plurality of detector pixels by determining a number of detector pixels at each of which the estimated first scatter distribution has a local maximum or a local minimum.