Shape Reconstruction of Objects in Participating Media by Combining Photometric Stereo and Optical Thickness

This paper proposes a method to reconstruct the 3D shape of objects in participating media. Shape reconstruction of objects in participating media, such as water, fog, and smoke, is difficult due to light scattering, which degrades image quality. While previous methods cope with this problem by removing the scattering components from images, the proposed method estimates optical thickness from images and uses it to recover the depth of the objects in participating media. With the proposed method, a detailed 3D shape is recovered using a photometric stereo technique that was designed to work in participating media. Three-dimensional global shapes that cannot be recovered by the photometric stereo technique, such as depth edges, are recovered from optical thickness. Experimental results with real images show that the proposed method correctly reconstructs the 3D shape of objects in participating media.