Opto-mechanical tilt sensor using moiré effect for slope movement remote sensing

A novel tilt sensing device using the circular grating moiré effect is proposed in this paper. The relationship of the tilt angle and the features extracted from moiré patterns was investigated through a controlled experiment. A prototype of the circular moiré tilt sensing device was designed and fabricated. Images of the moiré patterns were captured using a high-resolution web camera mounted onto the device. The principle of tilt detection using the circular moiré was demonstrated using the controlled experiment. The graphs obtained from the experiments show parabolic trends in the relationship between peak-to-valley height of the transformed polar curve and the tilt angle. The mean absolute error for y-z direction and x-z direction tilting is 0.216 and 0.183 respectively.