Systems, and method and computer readable media that store instructions for motion based object detection. The method may include receiving or generating a video stream that comprises a sequence of images; generating image signatures of the images; wherein each image is associated with an image signature that comprises identifiers; wherein each identifier identifiers a region of interest within the image; generating movement information indicative of movements of the regions of interest within consecutive images of the sequence of images; searching, based on the movement information, for a first group of regions of interest that follow a first movement; wherein different first regions of interest are associated with different parts of an object; and linking between first identifiers that identify the first group of regions of interest.