Scaled SFS method for Lambertian surface 3D measurement under point source lighting

Improved SFS 3D measurement based on BP neural network

Non-contact 3D surface measurement is an important problem for modern industry. Shape from shading (SFS) is a convenient method because it can recover the 3D shape only from one image. But the conventional SFS research has a lot of restriction, such as Lambertian illumination model. If the object isn’t under this model, the precision will decrease quickly. We proposed an improved SFS based on n...

Accuracy of Spherical Harmonic Approximations for Images of Lambertian Objects under Far and Near Lighting

Various problems in Computer Vision become difficult due to a strong influence of lighting on the images of an object. Recent work showed analytically that the set of all images of a convex, Lambertian object can be accurately approximated by the low-dimensional linear subspace constructed using spherical harmonic functions. In this paper we present two major contributions: first, we extend pre...

Method for Recovering 3d Surface Shape Based on Grayscale Structured Lighting

A mathematical and algorithmic study of the Lambertian SFS problem for orthographic and pinhole cameras

This report proposes a mathematical and algorithmic study of the Lambertian SFS problem for orthographic and pinhole cameras. Our approach is based upon the notion of viscosity solutions of Hamilton-Jacobi equations. This approach provides a mathematical framework in which we can prove the well-posedness of the problem (proof of the existence of a solution and characterization of all solutions)...

The 4-Source Photometric Stereo Under General Unknown Lighting

Many previous works on photometric stereo have shown how to recover the shape and reflectance properties of an object using multiple images taken under a fixed viewpoint and variable lighting conditions. However, most of them only dealt with a single point light source in each image. In this paper, we show how to perform photometric stereo with four images which are taken under distant but gene...