Spatio-temporal reconstruction of weak-texture wave fields using thermal stereo vision with active thermal texturing

Accurate measurement of weak-texture wave fields in laboratory experiments remains challenging due to the scarcity of natural visual features, which can compromise stereo correspondence and three-dimensional reconstruction. This study proposed a thermal stereo vision method for spatio-temporal reconstruction of weak-texture wave fields, based on a visual enhancement strategy that introduced active thermal texturing. A small amount of hot water was gently applied to the free surface, generating controllable temperature gradients that produced dense and spatially continuous thermal patterns without using physical tracers or dyes. These enhanced features enabled reliable correspondence estimation, which was further stabilized using a normalized cross-correlation (NCC)-based stereo matching method that improved matching robustness and disparity continuity under weak-texture infrared imaging conditions. Focused waves with varying steepnesses and periods were generated in a wave flume to evaluate the feasibility and accuracy of the method. Wave time series extracted from these reconstructions showed strong agreement with resistive wave gauge measurements, with period errors below 2%, amplitude errors within 8%, and coefficients of determination exceeding 0.95. The proposed approach provides a non-contact, full-field measurement tool for capturing the spatial structure and temporal evolution of weak-texture focused-wave fields under the tested laboratory conditions.