Development of deep-range and high-resolution laser 3D measurement system

Generally, deep measurement range and high resolution are the directly opposed functions in the laser triangular measurement system. In other words, measurement range was made shallow to raise its resolution. But it is asked to go together to raise both functions caused by the complicated 3D shape of industrial products. We have coped with both functions by the individual optical technology and the image processing technology. At first, we have used axicon lens to minimize laser beam spot. Though it was possible to minimize laser spot with spherical surface lens only at the just focused position. But we have succeeded to generate thin spot laser beam which diameter is less than 20μm whole the so deep 300mm range with axicon lens. The second is high precision gravity center calculation method using gaussian curve fitting. This method could achieve the high resolution as well which contained speckle noise and so on. The system has been made practical for portable phone, and we confirmed the predominance of the system.