An imaging system configured to acquire image projections of a subject, comprising: a source configured to emit x-rays as a whole beam having a whole cross-section area; a filter assembly, including: a filter member (510, 514, 518, 522) configured to occlude at least a portion of the cross-section area of the whole beam to form a partial beam, a filter carrier configured to move the filter member relative to the whole beam to cause the filter member to occlude at least a portion of the whole beam to form the partial beam and move the filter member (510, 514, 518, 522) away from the whole beam to allow passage of the whole beam; a detector configured to detect the x-rays in the whole beam and the partial beam; and a control system configured to control the movement of the filter member with the filter carrier to detecting the whole beam or the partial beam; a correction system configured to execute instructions to: determine scatter of x-rays at least at the detector in the partial beam, and determine projection correction to correct for scattering of the x-rays, wherein the filter member (510, 514, 518, 522) includes a first filter member and a second filter member; wherein the first filter member occludes a first portion of the whole beam to form a first partial beam and the second filter member occludes a second portion of the whole beam to form a second partial beam, wherein the first partial beam is detected at the detector to determine a first scattering in a first detector region and the second partial beam is detected at the detector to determine a second scattering in a second detector region, wherein the filter member (510, 514, 518, 522) further includes a third filter member and a fourth filter member; wherein the third filter member occludes a third portion of the whole beam to form a third partial beam and the fourth filter member occludes a fourth portion of the whole beam to form a fourth partial beam, wherein the third partial beam is detected at the detector to determine a third scattering in a third detector region and the fourth partial beam is detected at the detector to determine a fourth scattering in a fourth detector region, wherein the first detector region, the second detector region, the third detector region, and the fourth detector region are configured to overlap to allow for determination of scattering in four quadrants of the detector. a source configured to emit x-rays as a whole beam having a whole cross-section area; a filter assembly, including: a filter member (510, 514, 518, 522) configured to occlude at least a portion of the cross-section area of the whole beam to form a partial beam, a filter carrier configured to move the filter member relative to the whole beam to cause the filter member to occlude at least a portion of the whole beam to form the partial beam and move the filter member (510, 514, 518, 522) away from the whole beam to allow passage of the whole beam; a filter member (510, 514, 518, 522) configured to occlude at least a portion of the cross-section area of the whole beam to form a partial beam, a filter carrier configured to move the filter member relative to the whole beam to cause the filter member to occlude at least a portion of the whole beam to form the partial beam and move the filter member (510, 514, 518, 522) away from the whole beam to allow passage of the whole beam; a detector configured to detect the x-rays in the whole beam and the partial beam; and a control system configured to control the movement of the filter member with the filter carrier to detecting the whole beam or the partial beam; a correction system configured to execute instructions to: determine scatter of x-rays at least at the detector in the partial beam, and determine projection correction to correct for scattering of the x-rays, determine scatter of x-rays at least at the detector in the partial beam, and determine projection correction to correct for scattering of the x-rays, wherein the filter member (510, 514, 518, 522) includes a first filter member and a second filter member; wherein the first filter member occludes a first portion of the whole beam to form a first partial beam and the second filter member occludes a second portion of the whole beam to form a second partial beam, wherein the first partial beam is detected at the detector to determine a first scattering in a first detector region and the second partial beam is detected at the detector to determine a second scattering in a second detector region, wherein the filter member (510, 514, 518, 522) further includes a third filter member and a fourth filter member; wherein the third filter member occludes a third portion of the whole beam to form a third partial beam and the fourth filter member occludes a fourth portion of the whole beam to form a fourth partial beam, wherein the third partial beam is detected at the detector to determine a third scattering in a third detector region and the fourth partial beam is detected at the detector to determine a fourth scattering in a fourth detector region, wherein the first detector region, the second detector region, the third detector region, and the fourth detector region are configured to overlap to allow for determination of scattering in four quadrants of the detector.