A piston engine and a method for controlling a diesel-type piston engine including at least one combustion chamber formed by a cylinder. The release layer comprises a polyolefin block copolymer. A test image of the primary speckle pattern that is projected onto a surface of an object in the target region is captured and compared to the reference images so as to identify a reference image in which the primary speckle pattern most closely matches the primary speckle pattern in the test image.