Abstract
It has been widely known that most optical stylus instruments composed of laser diode and objective lens are troubled with peak noise as well as unreasonable high frequency component in the measured data due to non-uniform speckle pattern in the reflected light. To overcome this problem, a novel speckle noise compensation system was developed and consequently less high frequency components could be obtained. In order to improve its measuring performance, we provided with an additinal compensation system in the orthogonal direction and designed the selection technique between the two alternatives. This advanced optical measurement system demonstrated that the peak noise and high frequency component in the finally measured data are significantly decreased. So this technique can contribute to develop a more reliable optical stylus instrument.
