3D nonstationary local distance operator

In this paper, a 3D nonstationary local distance operator is introduced. This kind of operator is adapted to the measurement of distances between objects sampled on nonuniform grids. This operator can be regarded as a nonstationary version of local distance operators adapted to parallelepipedic (noncubic) grids. The principle of coefficient computation and spatial adaptation are given. An application to dissimilarity measurement between color images is presented. We compare the nonstationary local distance operator with two stationary versions: 1) images are sampled with the lowest sampling step; and 2) the local operator is designed according to the average voxel size