Using rigorous methods the authors have shown that the invariant direction of isophotes at parabolic points is the projection of the principal direction of zero curvature onto the image plane. They have gone beyond considering the limited case of pure orthographic projection and have shown under what conditions this photometric invariance property breaks down and is best approximated in perspective images, and for a nondistant light source. In addition to giving experimental evidence supporting their claim about how isophotes are parallel to the direction of zero curvature at parabolic points, the authors suggest possible applications of this geometric cue to determination of orientation and curvature at parabolic points. The best advantage taken from this geometric cue is when constraint information can be obtained, knowing absolutely nothing about the reflectance map. The true power of a physical invariant is the information it gives under the most generic conditions possible, in this case any type of smooth reflectance map.<>


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    A photometric invariant and shape constraints at parabolic points


    Contributors:
    Wolff, L.B. (author)


    Publication date :

    1990-01-01


    Size :

    628843 byte




    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English




    Recognizing 3D Objects Using Photometric Invariant

    Nagao, K. / IEEE Computer Society / Technical Committee on Pattern Analysis and Machine Intelligence | British Library Conference Proceedings | 1995


    Segmentation of Surface Curvature Using a Photometric Invariant

    Wolff, L. B. / Fan, J. / Institute of Electrical and Electronics Engineers; Computer Society | British Library Conference Proceedings | 1994


    Robust Photometric Invariant Region Detection in Multispectral Images

    Gevers, T. / Stokman, H. M. | British Library Online Contents | 2003


    Parabolic propagation-invariant optical beams

    Gutierrez-Vega, J.-C. / Bandres-Motola, M.A. / Ley-Koo, E. et al. | IEEE | 2003