Direct Use of Needle-Map

The needle-map is a valid representation for object recognition. In terms of dimensionality of the matching representation, it may be viewed as midway between model (3-D) and appearance-based (2-D) recognition. However, since a series of model needle-maps are needed for each object, it remains essentially an appearance-based technique. If we deal with unit normals, two values are sufficient to describe the direction of each normal, since the third component may be determined from the other two. Thus, matching can be performed using 2-D vectors.