Characterizing weld pool surfaces from polarization state of thermal emissions.

In this Letter, a vision-based remote sensing methodology is proposed to measure the topography of weld pool surfaces from one single view. Thermal radiations emitted by the hot liquid metal at a wavelength within the arc plasma blind spectral window are acquired by a wavefront division polarimetric system. The refractive index of the liquid metal and the topography of the weld pool surface are inferred from the polarimetric state of the thermal radiations.