Adaptive fringe projection method for high dynamic range objects measurement

Grating fringe projection 3D measurement techniques are extensively applied in various fields. However, in high dynamic range scenarios with significant surface reflectivity variations, uneven greyscale distribution may lead to phase errors and poor reconstruction results. To address this problem, an adaptive fringe projection method is introduced. The method involves projecting two sets of dark and light fringes onto the object, enabling the full-field projection intensity map to be generated adaptively based on greyscale analysis. First, dark fringes are projected onto the object to extend exposure time as long as possible without causing overexposure in the image. Subsequently, bright fringes are projected under the same exposure settings to detect overexposed pixels, and the greyscale distribution of these overexposed points from the previous dark fringe projection is analyzed to calculate the corresponding projection intensities. Finally, absolute phase information from orthogonal fringes is used for coordinate matching, enabling the generation of adaptive projection fringe patterns. Experiments on various high dynamic range objects show that compared to conventional fringe projection binocular reconstruction method, the proposed algorithm achieves complete reconstruction of high dynamic range surfaces and shows robust performance against phase calculation errors caused by overexposure and low modulation.