Abstract: Disclosed herein is an image sensor comprising: a first, a second, and a third radiation detectors, each of which comprising a planar surface to receive radiation from a radiation source; wherein the planar surfaces of the first radiation detector and the second radiation detector are not parallel, the planar surfaces of the second radiation detector and the third radiation detector are not parallel, and the planar surfaces of the third radiation detector and the first radiation detector are not parallel; wherein the first radiation detector, the second radiation detector and the third radiation detector are not arranged in the same row; wherein the first, the second and the third radiation detectors are configured such that the planar surface of each of them includes a position at which an angle of incidence of the radiation from the radiation source is 0°.