International Society for Industrial Process Tomography

A Fast Optical Tomography System Based on a Two-axis Scanning Mirror

Xiaoyang Tang, Zhang Cao and Lijun Xu^*

School of Instrumentation and Opto-Electronic Engineering, Beihang University, Beijing, China.

^*Email: lijunxu@buaa.edu.cn

ABSTRACT

In the measurement of gas-liquid two-phase flows, it is important to measure the shape and size of bubbles. Several tomographic methods have been proposed, including X-ray tomography, electrical tomography and optical tomography. X-ray tomography has not been widely used because of its radioactivity. As for electrical tomography, the spatial resolution is low due to the restricted number of the electrodes. In optical tomography, setting up several projection systems around the object is common. However, it is not enough for high resolution reconstruction, because only intensity data in a finite number of projection angles can be acquired. In this paper, a fast optical tomography system based on a two-axis MEMS scanning mirror is proposed. With the vibration of the scanning mirror, a continuous scanning trajectory on the diffuse-reflective material is formed, which leads to numerous projection angles of the object. Two different materials and three different distributions are tested in the ZAMAX simulation model and the inverse Radon transform is used for reconstruction. The simulation results show that the optical tomography system is of good feasibility.

Keywords high spatial resolution, optical tomography, two-axis scanning mirror, the inverse Radon transform

Industrial Application General