Noise analysis and signal-to-noise ratio model of gain modulation laser imaging

Gain modulation imaging technique is one of the prominent schemes for scannerless lidar. By controlling the gate width, it's easy to suppress backscatter noise and make the image more accurately. Imaging range and accuracy of gain modulation laser imaging become a research focus at present. According to the principle of imaging, the signal energy and the noise energy reaching the imager can be found. Further signal-to-noise ratio can be obtained. Previous theoretical models consider only linear gain condition. However the influence of laser pulse width and other factors are less taken into consideration. These models will have a certain deviation with the actual one. By simulating the nonlinear gain with consideration of the laser pulse width and lambert spherical radiation, more accurate SNR model of gain modulation laser imaging is obtained. On this basis, the established SNR model can be used to estimate the experimental distance with good imaging effect. It provides the theoretical basis for subsequent experiment system parameter selection and image processing.