Abstract
In this study, an optical noncontact measuring instrument has been developed to measure the 3-dimensional shape of an object with a free-form surface. A linearly polarized laser from the instrument is focused on the object surface to be measured. The astigmatic focus error method has been applied to the instrument in order to achieve a focused positioning signal of the object surface. The depolarized component of the light backscattered from the object surface has been detected as the signal. In the previous report, the power of the linearly polarized laser incident on the object surface was kept constant, and two detectors were used in the instrument. In this study, properties of the developed instrument are improved when light-detecting portions of the light detector are changed and the power of the laser light incident on the object surface is varied in order to obtain an appropriate detected light power. Only one detecter is used. Using this instrument, 3-D profiles of diffuse reflection surfaces and metal surfaces on which there are both specular reflection and diffuse reflection, can be measured.
