Subpixel imaging system with enhanced optical multiplexing.

Abstract

This paper presents a compact and high-efficiency solid-state three-dimensional (3D) light detection and ranging (LiDAR) system based on subpixel imaging and microlens array-based optical multiplexing. The proposed system integrates a two-dimensional laser diode array transmitter and a receiver composed of a projection lens, a microlens-based multiplexer, and a small-scale avalanche photodiode array. To overcome the limitations of traditional fiber bundle-based multiplexers, a dual-layer microlens array structure is developed, enabling precise subpixel focusing and enhanced spatial multiplexing. The system supports multiple encoding strategies-offering high-resolution imaging (640×480) when using less patterns with CMOS sensors (320×240) and fast 3D imaging when raising encoding counts for downscale detectors (2×2). Experimental results confirm the effectiveness of the design in both 3D point cloud reconstruction and 2D multiplexed imaging scenarios. The proposed architecture is scalable and suitable for integration with time-of-flight modules. This subpixel imaging technique can greatly reduce the number of detectors required in imaging LiDAR systems, making it suitable for low-cost LiDAR applications.