Tunable-density sharp spot array projection for 3D sensing using a single DOE

Structured light projection has been widely used for high-precision 3D sensing in computer vision. Diffractive approaches based on fixed components offer unique advantages over DLP or LCD projectors due to their compact size and low energy consumption. However, current methods using components such as diffractive optical elements (DOEs) or metasurfaces are typically designed to generate fixed patterns, limiting the adaptability in practical applications like adjusting sensor resolution and frame rates. In this paper, a single DOE-based projector with tunable spot array density is proposed. The property of tunable density is achieved through adjusting the distance between the laser source and DOE with no need to replace fixed components during 3D measurements. Simulation and experimental results of tunable-density sharp spot array structured light projection are presented, demonstrating the effectiveness of the proposed method.