Calibration method for a multi-focus microscopic 3D imaging system.

This Letter presents a novel, to the best of our knowledge, method to calibrate multi-focus microscopic structured-light three-dimensional (3D) imaging systems with an electrically adjustable camera focal length. We first leverage the conventional method to calibrate the system with a reference focal length f. Then we calibrate the system with other discrete focal lengths f by determining virtual features on a reconstructed white plane using f. Finally, we fit the polynomial function model using the discrete calibration results for f. Experimental results demonstrate that our proposed method can calibrate the system consistently and accurately.