1. A computed tomography (CT) apparatus, comprising: processing circuitry configured to obtain projection data representing an irradiance of radiation detected at a plurality of detectors and corresponding to a plurality of projection angles of a radiation source; obtain agate signal; select a subset of the projection data to be gated projection data corresponding to gated projection angles indicated by the gate signal; determine weighting-and-feathering coefficients according to the gated projections angles, the weighting-and-feathering coefficients mitigating an inequality of data redundancy of the gated projection data, wherein the inequality of the data redundancy is mitigated by increasing a first coefficient of the weighting-and-feathering coefficients above a threshold in relation to a second coefficient of the weighting-and-feathering coefficients being below the threshold, and a projection angle of the first coefficient being opposite to a projection angle of the second coefficient; reconstruct a tomographic image from the gated projection data using an iterative reconstruction method including a regularization term and using the weighting-and-feathering coefficients.