1. A distance measurement system, comprising: a light source module, for projecting a light beam with a speckle pattern to a plurality of reference flat surfaces and an object which are located at different position points so as to show a plurality of images with the speckle pattern on each of the reference flat surfaces and the object, wherein the speckle pattern has a plurality of speckles; an image capture device, for generating a plurality of reference image information through capturing the image with the speckle pattern projected on each of the plurality of reference flat surfaces and generating an object image information through capturing the image with the speckle pattern projected on the object; and a processing module, coupled to the image capture device, for generating a plurality of comparison results through comparing the plurality of reference image information with the object image information, and computing the position of the object through performing an interpolation operation to the plurality of comparison results.