This software is a component in an unmanned ground vehicle (UGV) perception system that builds compact, single-frame terrain maps for distribution to other systems, such as a world model or an operator control unit, over a local area network (LAN). Each cell in the map encodes an elevation value, terrain classification, object classification, terrain traversability, terrain roughness, and a confidence value into four bytes of memory. The input to this software component is a range image (from a lidar or stereo vision system), and optionally a terrain classification image and an object classification image, both registered to the range image. The single-frame terrain map generates estimates of the support surface elevation, ground cover elevation, and minimum canopy elevation; generates terrain traversability cost; detects low overhangs and high-density obstacles; and can perform geometry-based terrain classification (ground, ground cover, unknown).
A new origin is automatically selected for each single-frame terrain map in global coordinates such that it coincides with the corner of a world map cell. That way, single-frame terrain maps correctly line up with the world map, facilitating the merging of map data into the world map. Instead of using 32 bits to store the floating-point elevation for a map cell, the vehicle elevation is assigned to the map origin elevation and reports the change in elevation (from the origin elevation) in terms of the number of discrete steps. The single-frame terrain map elevation resolution is 2 cm. At that resolution, terrain elevation from –20.5 to 20.5 m (with respect to the vehicle’s elevation) is encoded into 11 bits.
For each four-byte map cell, bits are assigned to encode elevation, terrain roughness, terrain classification, object classification, terrain traversability cost, and a confidence value. The vehicle’s current position and orientation, the map origin, and the map cell resolution are all included in a header for each map. The map is compressed into a vector prior to delivery to another system.
This work was done by Arturo L. Rankin of Caltech for NASA’s Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Daniel Broderick of the California Institute of Technology at
This Brief includes a Technical Support Package (TSP).
Single-Frame Terrain Mapping Software for Robotic Vehicles
(reference NPO-47039) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA's Jet Propulsion Laboratory (JPL) detailing the Single-Frame Terrain Mapping Software for Robotic Vehicles, identified as NPO-47039. This software was developed as part of the Army Research Laboratory Demo III program and the DARPA PerceptOR program, aimed at enhancing robotic vehicle navigation and terrain analysis.
The core functionality of the software involves processing input from range images obtained through lidar or stereo vision systems. It can also utilize terrain and object classification images that are registered to the range image. The software generates a single-frame terrain map that estimates various elevations, including support surface elevation, ground cover elevation, and minimum canopy elevation. Additionally, it assesses terrain traversability costs, detects low overhangs and high-density obstacles, and performs geometry-based terrain classification, categorizing areas as ground, ground cover, or unknown.
One of the key features of the software is its ability to merge multiple single-frame maps into a composite world map. This composite map is crucial for planning safe paths for robotic vehicles, as it provides a more comprehensive view of the terrain by averaging elevation and cost data over the last three maps. The document also discusses the challenges associated with single-frame maps, such as noise and limited field of regard, which are addressed through temporal filtering techniques.
The document emphasizes the importance of this technology in various applications, particularly in military and research contexts, where accurate terrain mapping is essential for operational success. It highlights the potential for broader technological, scientific, and commercial applications stemming from these advancements in terrain mapping.
Overall, the Technical Support Package serves as a resource for understanding the capabilities and applications of the Single-Frame Terrain Mapping Software, showcasing JPL's commitment to innovation in robotic systems and their navigation technologies. For further inquiries or assistance, the document provides contact information for the Innovative Technology Assets Management at JPL.
