Normal vector vibration imaging using a correlation image sensor

In this paper, we propose a normal vector vibration imaging system using ring illumination and correlation image sensor. In this system, light source of the ring illumination rotates at a certain frequency in front of the object, and the object surface is actuated by air jet at other frequency. Then the reflected light intensity has some temporal frequency components including beat frequency between illumination frequency and vibrating frequency. Correlation image sensor demodulates those temporal frequency components in one frame, then normal vector vibration is calculated.