Search

Abstract: The Optical Microscope (OM) on the Phoenix Mars lander (operated from May through October 2008) was used to search for visible-wavelength luminescence of soil particles excited by ultraviolet (UV) illumination (λ=360–390nm). No luminescent particles were found, with the possible exception of a few potentially luminescent features comprising about 0.02% of the total soil volume. The luminescence quantum efficiency of bulk soil as well as individual soil particles at the Phoenix site is constrained to less than 0.04%. A similar UV experiment will be performed by the Mars Hand Lens Imager (MAHLI) on the upcoming Mars Science Laboratory (MSL) mission. We compare OM and MAHLI UV experiments to each other and suggest a strategy to search for UV-excited luminescence with MAHLI. [Copyright &y& Elsevier]

Abstract: The limited depth of focus of microscope optics precludes the observation of a three-dimensional surface in a single view. For an efficient operation of a planetary microscope observing a highly irregular surface, an autofocus algorithm must detect partially focused views and merge them into a completely focused image (extended depth of focus). In this paper we investigate the suitability of different algorithms for autonomous image focusing onboard a Mars lander. We show that all methods under study, except for the Variance method, produce reasonable results and that their performance depends (amongst other factors) on sample morphology. For reasons of simplicity and reduced computational requirements we favor Gradient and Roberts methods and present an efficient implementation thereof. [ABSTRACT FROM AUTHOR]