Shape in an image refers to the shape of the regions in an image.
Shape is well defined concept used for the computing the similarity between the images rather than the texture and color. Shape deals with the spatial information of an image.
[Biederman. 1987] proved that natural objects can be recognized by their shape. Shapes of all the objects in an image are computed to identify the objects in the image.
- Shapes with in the image can be represented in terms of curves, lines, eigen shapes, points, medial axis etc.
- Shapes can be expressed in terms of various descriptors like moments, Fourier descriptors, geometric and algebraic invariants, polygons, polynomials, splines, strings, deformable templates, and skeletons
http://sgo-feeds-dev.blogspot.co.uk/2012/11/shape-context-rotation-invariance.html
Firefly's space 