Optical Gas Imaging for Accurate Leakage Source Measurement Based on Optical Flow Analysis

Gas leakage measurement in industrial production is the key to eliminating accidents, ensuring that production can proceed smoothly and safely, and safeguarding the safety of personnel and the surrounding public. However, most of the existing gas leak point measurement methods use sensors for leak point measurement and cannot achieve long-range measurements. Gas infrared imaging can be applied in more industrial scenarios due to its advantage of wide-range noncontact telemetry. However, the problem with existing algorithms for leakage source measurement based on infrared images is mostly applicable for close-range detection of small targets, which implies that they cannot take advantage of the long-range, and wide-range applications of infrared gas imaging. When the contrast between gas and background is low or when large-scale leakage occurs, the existing measurement algorithms have low accuracy and are easily disturbed by noise, which does not meet the requirements of gas monitoring in industrial environments. To solve the issues, we propose a leak source measurement method based on the gas concentration and optical flow method. Here, the direct method (DM) and grid method (GM) are discussed to determine the region where the gas leakage source is located, which is uniquely combined with the main path direction of the gas, that is, obtained by the Farneback optical flow method. The experimental results show that the judgment and measurement error of GM combined with the Farneback optical flow method after Kalman filtering is within 65 pixels, that is, corresponding to a distance of 30 m from the leakage point can be controlled within 1.35 m, which can realize the automatic measurement of remote leakage points.