Visualization of water vapor distribution using near-infrared light

Water vapor adversely affects the quality of industrial products and food materials. To identify and control the flow and sources of water vapor, the spatial distribution of water vapor needs to be measured. Therefore, we conducted a water vapor flow visualization experiment using near-infrared spectroscopy and attempted to image water vapor distributions. The measurement system was equipped with high-power-tunable-laser and large telecentric lens using optimum wavelength from the near-infrared spectrum. The obtained 2D images were processed, and the flow of water vapor in the image were estimated. In this study, we investigated the evaporation process from liquid water surface and evaluated the effectiveness of the imaging system.