  The present article proposes an approach to analyze the photometric
properties of the surface materials from multi-angle observations acquired by
the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the
Mars Reconnaissance Orbiter. We estimate photometric parameters using Hapke
model in a Bayesian inversion framework. This work also represents a validation
of the atmospheric correction provided by the Multi-angle Approach for
Retrieval of Surface Reflectance from CRISM Observations (MARS-ReCO) proposed
in the companion article.The latter algorithm retrieves photometric curves of
surface materials in reflectance units after removing the aerosol contribution.
This validation is done by comparing the estimated photometric parameters to
those obtained from in situ measurements by Panoramic Camera instrument at the
Mars Exploration Rover (MER)-Spirit and MER-Opportunity landing sites.
Consistent photometric parameters with those from in situ measurements are
found, demonstrating that MARS-ReCO gives access to accurate surface
reflectance. Moreover the assumption of a non-Lambertian surface as included in
MARS-ReCO is shown to be significantly more precise to estimate surface
photometric properties from space in comparison to methods based on a
Lambertian surface assumption. In the future, the presented method will allow
us to map from orbit the surface bidirectional reflectance and the related
photometric parameters in order to characterize the Martian surface.
