Geology topics

Benjamin H Wheeler

Publications and source records attributed to Benjamin H Wheeler.

4 recordsLinked to original sources

USGS2025

Medium resolution lunar topography: An updated view of the lunar surface from stereophotogrammetrically derived DTMs

Digital Terrain Models (DTMs) are essential for lunar exploration, supporting critical applications such as landing site selection,mission planning, and in situ resource utilization. This study presents a comprehensive reprocessing of the Kaguya Terrain Camera (TC) dataset using the NASA Ames Steropipeline to generate over 130,000 medium-resolution DTMs with nearly global lunar coverage to ±70°. We observed significant bowing in the DTMs derived using the publicly available interior orientation and have used a novel technique, in the planetary sciences, to re-estimate the boresight and eight-parameter distortion coefficients. Inter-DTM vertical alignment errors are also present due to spacecraft jitter and we present the methodology used to jitter correct the DTMs. DTMs are aligned to the Lunar Orbiter Laser Altimeter (LOLA) point cloud and absolute errors are mean centered to zero with a mean standard deviation of 24 meters. Leveraging advanced stereophotogrammetry techniques, updated sensor models, and rigorous alignment to the Lunar Orbiter Laser Altimeter (LOLA) dataset, we achieved horizontal accuracies inside the orthoimage resolution (mean of 30 meters per pixel) and 2-4 meters vertically. These high-quality DTMs serve as critical inputs for planetary science, engineering, and future lunar mission planning. The methods and insights gained from this large-scale processing effort establish a framework for automating DTM derivation on other planetary bodies.

Conference Paper↗

USGS2024

Current status of the community sensor model standard for the generation of planetary digital terrain models

The creation of accurate elevation models (topography) from stereo images are critical for a large variety of geospatial activities, including the production of digital orthomosaics, change detection, landing site analysis, geologic mapping, rover traverse planning, and spectral analysis. The United Stated Geological Survey, Astrogeology Science Center, continues to transition the supported planetary sensor models to the Community Sensor Model (CSM) standard. This paper describes the current state of use for this photogrammetric standard, supported sensor model types, and qualitatively compares derived topography between SOCET SET and SOCET GXP ( ® BAE Systems) using HiRISE stereo images of Mars. Our transition to the CSM standard will ensure an uninterrupted capability to make these valuable products for Mars and many other extraterrestrial planets and moons.

Remote Sensing↗

USGS2022

Comparison of Digital Terrain Models from two photoclinometry methods

We evaluate the horizontal resolution and vertical precision for digital topographic models (DTMs) of the Moon derived from image radiance information, a process known as photoclinometry (PC) or shape-from-shading (SfS). We use the implementations in two available planetary image processing software systems, single image PC in the U.S. Geological Survey Integrated Software for Imagers and Spectrometers (ISIS) system, and multi-image SfS in the Ames Stereo Pipeline (ASP), and test results obtained with and without use of a starting solution from stereo, with single and multiple images, and for varying illumination conditions. To obtain the higher quality reference DTMs against which the products can be evaluated, we derived DTMs by stereoanalysis of Lunar Reconnaissance Orbiter Narrow-Angle Camera (LROC NAC) images at their native pixel spacing of ∼0.5 m, then produced a 16-m/post stereo DTM from images downsampled to 4 m/pixel and refined it with images at 16 m/pixel. When used with a single image, both algorithms improved resolution (by a factor of 1.4 for PC and 2.4 for SfS compared to stereo). An albedo map produced in ISIS by ratioing the image to a simulation based on the stereo DTM was well correlated with one output by SfS. The albedo correction was crucial for PC with ∼60° incidence but not at ∼80°. DTMs produced by PC and SfS without a starting stereo DTM had larger errors but good detail, and could be useful for many applications. In SfS, it was necessary to increase smoothing to get a usable DTM when the weighting on an a priori DTM was reduced. Multi-image SfS including modeling of spatially varying albedo reduced vertical errors by factors of 1.5 or more compared to single-image SfS.

International Archives of the Photogrammetry, Remo↗

USGS2021

Improving the usability of Galileo and Voyager images of Jupiter’s moon, Europa

NASA's Voyager 1, Voyager 2, and Galileo spacecraft acquired hundreds of images of Jupiter's moon Europa. These images provide the only moderate- to high-resolution views of the moon's surface and are therefore a critical resource for scientific analysis and future mission planning. Unfortunately, uncertain knowledge of the spacecraft's position and pointing during image acquisition resulted in significant errors in the location of the images on the surface. The result is that adjacent images are poorly aligned, with some images displaced by more than 100 km from their correct location. These errors severely degrade the usability of the Voyager and Galileo imaging data sets. To improve the usability of these data sets, we used the U.S. Geological Survey Integrated Software for Imagers and Spectrometers to build a nearly global image tie-point network with more than 50,000 tie points and 135,000 image measurements on 481 Galileo and 221 Voyager images. A global least-squares bundle adjustment of our final Europa tie-point network calculated latitude, longitude, and radius values for each point by minimizing residuals globally, and resulted in root mean square (RMS) uncertainties of 246.6 m, 307.0 m, and 70.5 m in latitude, longitude, and radius, respectively. The total RMS uncertainty was 0.32 pixels. This work enables direct use of nearly the entire Galileo and Voyager image data sets for Europa. We are providing the community with updated NASA Navigation and Ancillary Information Facility Spacecraft, Planet, Instrument, C-matrix (pointing), and Events kernels, mosaics of Galileo images acquired during each observation sequence, and individual processed and projected level 2 images.

Earth and Space Science↗