A resistance circuit included in a semiconductor apparatus, which is formed of a plurality of thin film metal resistors connected in series, capable of achieving a precise resistance adjustment over a wide range by disconnecting or changing the resistors by laser beam irradiation. A method and a computer program product for generating 3D images are provided. Signals based on the detected radiation are used, together with spatial information of the transmitters and sensors, to calculate reflectivity coefficients for points of interest in the scene.