Abstract
This paper presents the experimental results for the depth measurement of small particles using a depth-from-defocus technique. In this technique, the depth of each particle is estimated by evaluating the image blur of the particle from a pair of blurred images simultaneously taken with different camera settings. A pair of blurred images is captured in this study be means of an optical system with a single 3CCD color camera and two color filters. The small particles are illuminated by a stroboscope synchronized with the VD signal of the CCD camera to eliminate the blurring caused by the motion of the particles. Experiment is performed for the cubic cavity flow induced by a rotating disk that is the upper wall of the cubic cavity. The experimental results show the applicability of the present method to 3-D particle image velocimetry.
