A dual-mode laser gated 3D and thermal imager on a single MCT-APD focal plane array

To address the challenges of hardware redundancy and data registration in traditional multi -sensor systems for fusing three-dimensional (3D) imaging with infrared thermal imaging, this paper proposes a compact dual -mode imaging scheme based on a single Mercury Cadmium Telluride Avalanche Photodiode (HgCdTe APD) focal plane array (FPA). An imaging system was designed around an HgCdTe APD FPA, with its ability to operate in both active gated 3D imaging and passive mid-wave infrared (MWIR) imaging modes demonstrated via a filter switching mechanism. Experiments demonstrate that in the passive mode, the system delivers thermal imaging performance with a Noise Equivalent Temperature Difference (NETD) of ~48 mK. In the active mode, 3D reconstruction of a real target located at 868.7 m is realized using an improved delayed step-gating method, yielding a ranging accuracy of 3.4 m.This study presents a viable technical approach to dual-mode imaging based on a single detector.