This paper presents a passive polarimetry method using a division of aperture optical device in order to segment the weld pool surface of the welding. Due to the high specularity of the surface of the weld pool, we use polarimetric data in order to facilitate it's segmentation in the liquid state. In this paper, we propose to combine two segmentation methods: Watershed Transform and the Level Set to ensure a better result. Our ultimate goal of this study is to provide real-time quality control of the surface of molten metal during the welding process while utilizing the additional information provided by the polarimetric data. Polarimetric imaging; segmentation; specular surface; welding process; weld pool surface TRANSPARENT OBJECTS; SURFACE ORIENTATIONS; POLARIZATION STATE