An image processing system, comprising: an at least two-channel X-ray imager for supplying a first stream of frames acquired at a first projection direction relative to an object of interest and a second stream of frames being acquired at a second projection direction relative to the object, the frames of the two streams being alternately acquired; an input interface for receiving i) from the first stream, first and second frames, the first frame being acquired before the second frame; ii) from the second stream, a third frame; an estimator configured to compute from the first frame and the later acquired second frame an estimated frame, wherein the estimator is configured to morph the estimated frame towards the third frame; an image merger which is configured to merge the so morphed estimated frame with the third frame so as to improve a signal-to-noise ratio in the third frame or which is configured to merge the new estimated or interpolated frame with the second frame so as to improve a signal-to-noise ratio in the second frame, wherein the merging includes a soft thresholding; an aligner configured to temporally align the estimated frame with the third frame of the second stream; an output interface configured to output said estimated frame and the third frame as a pair of temporally aligned frames; and a screen (M) for displaying images based on the output pairs of temporally aligned frames for the two streams. an at least two-channel X-ray imager for supplying a first stream of frames acquired at a first projection direction relative to an object of interest and a second stream of frames being acquired at a second projection direction relative to the object, the frames of the two streams being alternately acquired; a first stream of frames acquired at a first projection direction relative to an object of interest and a second stream of frames being acquired at a second projection direction relative to the object, the frames of the two streams being alternately acquired; an input interface for receiving i) from the first stream, first and second frames, the first frame being acquired before the second frame; ii) from the second stream, a third frame; an estimator configured to compute from the first frame and the later acquired second frame an estimated frame, wherein the estimator is configured to morph the estimated frame towards the third frame; i) from the first stream, first and second frames, the first frame being acquired before the second frame; ii) from the second stream, a third frame; an image merger which is configured to merge the so morphed estimated frame with the third frame so as to improve a signal-to-noise ratio in the third frame or which is configured to merge the new estimated or interpolated frame with the second frame so as to improve a signal-to-noise ratio in the second frame, wherein the merging includes a soft thresholding; an aligner configured to temporally align the estimated frame with the third frame of the second stream; an output interface configured to output said estimated frame and the third frame as a pair of temporally aligned frames; and a screen (M) for displaying images based on the output pairs of temporally aligned frames for the two streams. <EOS>