Local experts have been used to great effect for fitting deformable
models to images. Typically, the best location in
an image for the deformable model’s landmarks are found
through a locally exhaustive search using these experts. In
order to achieve efficient fitting, these experts should afford
an efficient evaluation, which often leads to forms with restricted
discriminative capacity. In this work, a framework
is proposed in which multiple simple experts can be utilized
to increase the capacity of the detections overall. In particular,
the use of a mixture of linear classifiers is proposed,
the computational complexity of which scales linearly with
the number of mixture components. The fitting objective is
maximized using the expectation maximization (EM) algorithm,
where approximations to the true objective are made
in order to facilitate efficient and numerically stable fitting.
The efficacy of the proposed approach is evaluated on the
task of generic face fittin...
Jason M. Saragih, Simon Lucey, Jeffrey F. Cohn