Dense-fog removal method via dual-transmittance fusion based on active range-gated detection

The image quality would be significantly degraded due to light scattering for the foggy scenes, and the imaging effect of the existing defogging method is limited due to the insufficiency of estimation accuracy on light transmittance. To address this problem, the paper proposes an image reconstruction method based on active range-gated imaging mechanism by fusing two kinds of transmittance. The fusion strategy based on weight allocation and optimal selection is developed through experimentally characterizing the actual accuracy of two transmittances. The fusion weights depending on fog density is derived, achieving accurate acquisition of transmittance from low to high fog concentrations. By fabricating active range-gated imaging system, defogging experiments are conducted. The results demonstrate that the proposed method can effectively recover target contours and details in foggy environments with an optical thickness of up to 10.53, and peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM) is improved by at least 15.4% compared with existing dehazing techniques, highlighting its potential for widespread application in target detection and recognition.