Robert G. Deen

Spectrophotometric properties of materials observed by Pancam on the Mars Exploration Rovers: 2. Opportunity

[1]xa0The Panoramic Camera (Pancam) on the Mars Exploration Rover Opportunity acquired visible/near-infrared multispectral observations of soils and rocks under varying viewing and illumination geometries that were modeled using radiative transfer theory to improve interpretations of the microphysical and surface scattering nature of materials in Meridiani Planum. Nearly 25,000 individual measurements were collected of rock and soil units identified by their color and morphologic properties over a wide range of phase angles (0–150°) at Eagle crater, in the surrounding plains, in Endurance crater, and in the plains between Endurance and Erebus craters through Sol 492. Corrections for diffuse skylight incorporated sky models based on observations of atmospheric opacity throughout the mission. Disparity maps created from Pancam stereo images allowed inclusion of local facet orientation estimates. Outcrop rocks overall exhibited the highest single scattering albedos (≤0.9 at 753 nm), and most spherule-rich soils exhibited the lowest (≤0.6 at 753 nm). Macroscopic roughness among outcrop rocks varied but was typically larger than spherule-rich soils. Data sets with sufficient phase angle coverage (resulting in well-constrained Hapke parameters) suggested that models using single-term and two-term Henyey-Greenstein phase functions exhibit a dominantly broad backscattering trend for most undisturbed spherule-rich soils. Rover tracks and other compressed soils exhibited forward scattering, while outcrop rocks were intermediate in their scattering behaviors. Some phase functions exhibited wavelength-dependent trends that may result from variations in thin deposits of airfall dust that occurred during the mission.

Remote image analysis for Mars Exploration Rover mobility and manipulation operations

NASAs Mars Exploration Rovers are two six-wheeled, 175-kg robotic vehicles which have operated on Mars for over a year as of March 2005. Each rover is controlled by a team who must understand the rovers surroundings and develop command sequences on a daily basis. The tight tactical planning timeline and ever-changing environment call for tools that allow quick assessment of potential manipulator targets and traverse goals, since command sequences must be developed in a matter of hours after receipt of new data from the rovers. Reachability maps give a visual indication of which targets are reachable by each rovers manipulator, while slope and solar energy maps show the rover operator which terrain areas are safe and unsafe from different standpoints.

Instrument deployment testbed: For planetary surface geophysical exploration

This paper describes a high fidelity mission concept systems testbed at JPL that was used to support the InSight (Interior Exploration Using Seismic Investigations, Geodesy, and Heat Transport) mission concept study. The InSight mission would conduct geophysical exploration of Mars interior using three instruments 1. SEIS seismometer monitors seismic activity and tidal displacements; 2. RISE X-band radio Doppler tracking experiment measures rotational variations; and 3. HP3: Heat-flow and Physical Properties Probe determines the geothermal heat flux. CNES contributes SEIS and DLR contributes HP3. The measurements from these instruments would yield information about processes that occurred during the initial accretion of the planet, the formation and differentiation of its core, crust, and mantle, and subsequent evolution of its interior. The SEIS and HP3 instruments will be deployed to the surface of Mars using a robotic arm similar to the robotic arm used on the Mars Phoenix Lander mission and operational experience inherited from Phoenix and MER. The SEIS and HP3 will be monitored every three hours for one Mars year, with no ground-in-the-loop interaction required. InSight was one of three proposed missions selected by NASA Discovery Program in May 2011 for funding to conduct preliminary design studies and analyses. InSight was selected in August 2012 as the 12th mission in the NASA Discovery Program.

A common interface for stereo viewing in various environments

This paper presents a graphical software infrastructure for stereo display. It enables the development of low-cost/short development cycle stereo applications that are portable - not only across platforms, but across display types as well. Moreover, it allows not just images but entire GUIs (Graphics User Interface) to be displayed in stereo consistently across many platforms. Java Advanced Display Infrastructure for Stereo (JADIS) provides a common interface for displaying GUI components in stereo using either specialized stereo display hardware (e.g. liquid crystal shutter or polarized glasses) or anaglyph display (red/blue glasses) on standard computer displays. An application using this toolkit will work without modification in either environment, allowing stereo software to reach a wider audience (anaglyphs) without sacrificing high-quality display on dedicated hardware. JADIS has been released as Open Source and is available via the Open Channel foundation website[1]. It has been integrated into several applications for stereo viewing and processing of data acquired by current and future NASA Mars surface missions (e.g. Mars Exploration Rover (MER), Phoenix Lander, Mars Science Laboratory (MSL)).

Modeling the effects of distortion, contrast, and signal-to-noise ratio on stereophotogrammetric range mapping

Stereophotogrammetry typically employs a pair of cameras, or a single moving camera, to acquire pairs of images from different camera positions, in order to create a three dimensional ‘range map’ of the area being observed. Applications of this technique for building three-dimensional shape models include aerial surveying, remote sensing, machine vision, and robotics. Factors that would be expected to affect the quality of the range maps include the projection function (distortion) of the lenses and the contrast (modulation) and signal-to-noise ratio (SNR) of the acquired image pairs. Basic models of the precision with which the range can be measured assume a pinhole-camera model of the geometry, i.e. that the lenses provide perspective projection with zero distortion. Very-wide-angle or ‘fisheye’ lenses, however (for e.g. those used by robotic vehicles) typically exhibit projection functions that differ significantly from this assumption. To predict the stereophotogrammetric range precision for such applications, we extend the model to the case of an equidistant lens projection function suitable for a very-wide-angle lens. To predict the effects of contrast and SNR on range precision, we perform numerical simulations using stereo image pairs acquired by a stereo camera pair on NASA’s Mars rover Curiosity. Contrast is degraded and noise is added to these data in a controlled fashion and the effects on the quality of the resulting range maps are assessed.

Spectral calibration in hyperspectral sounders

It is widely accepted that the knowledge of the frequencies of the spectral response functions (SRF) of the channels of hyperspectral sounders at the 10 parts per million (ppm) of frequency level is adequate for the retrieval of temperature and moisture profiles and data assimilation for weather forecasting. However, SI traceability and knowledge at the 1 ppm level and better are required to separate artifacts in the knowledge of the SRF due to orbital and seasonal instrument effects from diurnal and seasonal effects due to climate change. We use examples from AIRS to discuss a spectral calibration that uses the SI traceable upwelling radiance spectra to achieve an absolute accuracy of 0.5 ppm.