Mechanism of multi-wavelength laser detection of micro-camera

Based on the detection and transmission characteristics of different wavelength bands of lasers, by analyzing the echo transmission characteristics of typical micro-cameras, a research scheme for multi-wavelength laser feature detection of micro-camera was proposed. The theories of geometric optics and wave optics were used to analyze the structure of the micro-camera and its reflection spectral characteristics, and the echo light field at a certain detection distance was calculated and simulated. On this basis, a multi-wavelength laser detection system was built. The experimental results show that within a certain depth of field, the micro-camera with infrared cut-off filter has the obvious echo spot diffraction ring characteristics for visible light, high fringe contrast and long detectable distance; in the near-infrared band, the target echo power is low, the back-scattering interference is serious, and the detectable distance is short; the short-wave infrared band is hardly affected by the infrared cut-off filter, and 1 550 nm is in the eye-safe band. The experimental results are consistent with the numerical analyses and theoretical simulation results, which indicate the feasibility of short-wave infrared laser detection of micro-camera.