The problem of estimating an illumination distribution from images is called inverse lighting. For inverse lighting, three approaches have been developed based on specular reflection components, diffuse reflection components, and cast shadows. The present study provides theoretical insights as to why the approach based on cast shadows works in a reliable manner, and discusses what kind of basis functions are appropriate to be used for recovering illumination from cast shadows. First, we formalize the approach based on cast shadows by using spherical harmonics. Then, we analyze the approach in the frequency domain and show the advantages and the limitations of the approach. Second, motivated by the observations in the frequency domain, we propose an efficient method using Haar wavelets that provide compact supports and sparsity of coefficients. Finally, we report the results of experiments that compared the method using spherical harmonics and the method using Haar wavelets.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Spherical harmonics vs. Haar wavelets: basis for recovering illumination from cast shadows


    Contributors:
    Okabe, T. (author) / Sato, I. (author) / Sato, Y. (author)


    Publication date :

    2004-01-01


    Size :

    367561 byte





    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English



    Spherical Harmonics vs. Haar Wavelets: Basis for Recovering Illumination from Cast Shadows

    Okabe, T. / Sato, I. / Sato, Y. et al. | British Library Conference Proceedings | 2004



    Stability Issues in Recovering Illumination Distribution from Brightness in Shadows

    Sato, I. / Sato, Y. / Ikeuchi, K. et al. | British Library Conference Proceedings | 2001


    Detailanalyse des Hirndrucks mit HAAR-Wavelets

    British Library Online Contents | 2008