Three-dimension deformation measurement using modified microscopic stereo-vision technology

Abstract

An improved microscopic stereo-vision technology was developed for microscopic deformation (displacement and strain) measurement. First, the distortion of the microscope lens is significant, but the existing internal parameters calibration approach is prone to abnormal calibration results due to the parameter coupling. An innovative calibration method based on a modified homography transformation model is proposed. Second, the short working distance and the stereo angle of the two cameras lead to the degradation of image quality, and the correlation analysis is challenged. The genetic algorithm (GA) was modified and introduced in three-dimensional digital image correlation (3D-DIC) to help search for more accurate initial values of the displacement. The proposed GA-assisted DIC shows higher subpixel precision and speed in the image-matching test. Then, the developed microscopic stereo-vision technology incorporating the above innovative innovations is applied to a mechanical properties experiment with a 3D-printed artificial bone scaffold.