An image noise compensating system, comprising: a distance determining device, configured to determine whether a distance is larger than a distance threshold or not; an image sensor, comprising at least one image sensing unit, wherein the image sensor forms a combined image sensing unit when the distance is smaller than the distance threshold and senses images without forming the combined image sensing unit when the distance is larger than the distance threshold, wherein a width of an area that the combined image sensing unit can sense is larger than a width of an area that the image sensing unit can sense; a noise compensating circuit, configured to compensate image noises; and a control circuit, configured to calculate a location of the image noise compensating system.