  This paper presents a convenient graphical tool for encoding visual patterns
(such as image patches and image atoms) as point constellations in a space
spanned by perceptual features and with a clear geometrical interpretation.
General theory and a practical pattern encoding scheme are presented, inspired
by encoding polarization states of a light wave on the Poincare sphere. This
new pattern encoding scheme can be useful for many applications in image
processing and computer vision. Here, three possible applications are
illustrated, in clustering perceptually similar patterns, visualizing
properties of learned dictionaries of image atoms and generating new
dictionaries of image atoms from spherical codes.
