Reconstruction method for highly curved surfaces using bi-direction laser speckle

The inability of single-direction speckle projection to fully cover large-curvature surfaces limits the reconstruction accuracy and surface completeness. This study proposes a method for high-precision 3D reconstruction of large-curvature surfaces, using a multi-camera array combined with laser-projected speckles. A low-cost laser speckle projection device is developed to generate speckle patterns, with the optimal distance for speckle generation determined based on the relationship between the frosted glass and lenses. The mathematical relationship between the number of overlapping speckle layers and the normalized cross-correlation coefficient is derived, highlighting the impact of overlapping speckles on binocular stereo matching. To enhance the matching accuracy, a solution combining Gaussian pre-filtering and locally adaptive gamma correction is introduced. Multi-view speckle patterns are then synchronously captured using a stable multi-camera array. Experiments demonstrate that the proposed bi-directional projection and multi-camera array combination achieves superior reconstruction accuracy and completeness, with a relative error of 0.1% in the reconstruction of a semicylindrical surface and excellent performance in recovering complex surface morphologies, validating the effectiveness of the method.