  In the present work we focus on future experiments using cluster abundance
observations to constraint the Dark Energy equation of state parameter, w. To
obtain tight constraints from this kind of experiment, a reliable sample of
galaxy clusters must be obtained from deep and wide-field images. We therefore
present the computational environment (2DPHOT) that allow us to build the
galaxy catalog from the images and the Voronoi Tessellation cluster finding
algorithm that we use to identify the galaxy clusters on those catalogs. To
test our pipeline with data similar in quality to what will be gathered by
future wide field surveys, we process images from the Deep fields obtained as
part of the LEGACY Survey (four fields of one square degree each, in five
bands, with depth up to r'=25). We test our cluster finder by determining the
completeness and purity of the finder when applied to mock galaxy catalogs made
for the Dark Energy Survey cluster finder comparison project by Risa Wechsler
and Michael Busha. This procedure aims to understand the selection function of
the underlying dark matter halos.
