5/spl plusmn/2 eigenimages suffice: an empirical investigation of low-dimensional lighting models
Recently, P.W. Hallinan (1994) proposed a low dimensional lighting
model for describing the variations in face images due to altering the
lighting conditions. It was found that five eigenimages were sufficient
to model these variations. This report shows that this model can be
extended to other objects, in particular to those with diffuse
specularities and shadows. We find that sharp specularities and shadows
cannot be well represented by a low dimensional model. However, both
effects can be adequately described as residuals to such a model. We can
deal with occluders in a similar way. We conclude that low dimensional
models, using 5±2 eigenimages, can be usefully extended to
represent arbitrary lighting for many different objects. We discuss
applications of these results to object recognition