File:Partial features 3d.png

Fair use of part of a figure from an academic publication: 3D Object Modeling and Recognition Using Local Affine-Invariant Image Descriptors and Multi-View Spatial Constraints, Rothganger et al ICCV 2004.

Rationale: This image illustrates the construction of a 3D model from features, used to illustrate a prototypical method for object recognition, on 3D_single_object_recognition. It would be rather difficult although not impossible to create this figure as a "free-as-in-libre" work.