位相シフトデジタルホログラフィによる三次元計測システムの開発

抄録

In these years, demand for three-dimensional measurement technology is higher. However, in many of the traditional three-dimensional measurement methods, such as the method using phase shift patterns projection, it is difficult to measure shape of specular reflective and transparent objects, because power of reflected light is too high from specular reflective objects or too low from transparent objects, so that information of reflected light cannot be acquired accurately by digital camera. Digital holography has been used for resolving this problem. In traditional digital holography, interference fringe of measure object's light wave and reference light wave is recorded by digital camera. Using Fresnel diffraction principle, phase information of measure object's light wave can be required and shape of measure object can be calculated using interferometry principle. It can be used for reflective and transparent objects measurement, but as the principle of Fresnel diffraction, DC and conjugate components exist in calculated phase information as noises, so accuracy of measurement is lower. Phase shift digital holography is able to remove noises using special devices to change phase of reference light wave, but the devices are high price and the system is complex, so practical application of phase shift digital holography is difficult. In this paper, we propose a new method of phase shift digital holography using light detection principle. Simultaneously, we propose a digital holography reconstruction method using the convolution approach rather than the traditional Fresnel approach. The proposal method realized a compact phase shifting holography system with low price and a high accuracy three-dimensional measurement method. Therefore, we are able to realize the practical applications of digital holography with low price and higher accuracy.