A method for determining depth motion relative to a time-of-flight camera in a scene sensed by the time-of-flight camera, the method comprising: receiving a sequence of phase images of the scene, wherein the individual phase images of the sequence of phase images are captured sequentially by the time-of-flight camera at consecutive time instants, and wherein each phase image of the sequence of phase images comprises a plurality of pixels each representing a phase value; producing a two-dimensional depth image or a three-dimensional point cloud representing the scene from the sequence of phase images; determining a first auxiliary depth image from a first set of phase images out of the sequence of phase images; determining a second auxiliary depth image from a second set of phase images out of the sequence of phase images, wherein the first set of phase image and the second set of phase images are subsets of the sequence of phase images, and wherein the phase images of the second set of phase images are different from the phase images of the first set of phase images; and determining information about depth motion for at least part of the scene based on a comparison of depth values represented by pixels in the first auxiliary depth image and the second auxiliary depth image, wherein the information about depth motion indicates a) a relative change in distance between an object in the scene and the time-of-flight camera that occurs while the sequence of phase images is taken by the time-of-flight camera or b) a velocity of the object's depth motion relative to the ToF camera while the sequence of phase images is taken by the time-of-flight camera. receiving a sequence of phase images of the scene, wherein the individual phase images of the sequence of phase images are captured sequentially by the time-of-flight camera at consecutive time instants, and wherein each phase image of the sequence of phase images comprises a plurality of pixels each representing a phase value; producing a two-dimensional depth image or a three-dimensional point cloud representing the scene from the sequence of phase images; determining a first auxiliary depth image from a first set of phase images out of the sequence of phase images; determining a second auxiliary depth image from a second set of phase images out of the sequence of phase images, wherein the first set of phase image and the second set of phase images are subsets of the sequence of phase images, and wherein the phase images of the second set of phase images are different from the phase images of the first set of phase images; and determining information about depth motion for at least part of the scene based on a comparison of depth values represented by pixels in the first auxiliary depth image and the second auxiliary depth image, wherein the information about depth motion indicates a) a relative change in distance between an object in the scene and the time-of-flight camera that occurs while the sequence of phase images is taken by the time-of-flight camera or b) a velocity of the object's depth motion relative to the ToF camera while the sequence of phase images is taken by the time-of-flight camera.