A novel 3D optical sensing system with real-time processing has been developed which is capable of scanning a target at very high speeds (greater than 500,000 3D points/second).
Our high-speed, high-resolution 3D imaging sensor can perform many of the 3D imaging functions needed for surface robots/rovers and space or atmospheric vehicles in the exploration program: creation of planetary terrain maps, ranging, avoidance of surface hazards, imaging and motion sensing for automated rendezvous, docking for robot assisted assembly and surface operations. The sensor will have the capability to detect and profile targets and terrain at much higher speeds and resolution than existing systems at midrange distances (from centimeters to meters), giving a greater level of autonomy, safety, and capability to these operations.
The system was developed for the NASA Mars Rover Program and for inspection of the Shuttle Thermal Protection System. It supports the exploration mission by providing excellent near- to mid-range vision for various robotic applications.
Right: Penny scan -- one million 3D points in 2 seconds.
Our current research and development effort involves extending the High Speed 3D Scanner to meet additional NASA applications. As technical requirements are defined custom hardware is built and optimized to meet demands. We are currently focusing on the following three applications: Mars rover instrument placement, a portable high-resolution defect assessment instrument, and in-flight inspection of the Shuttle.
Mars Rover Instrument Placement
In a recent Director’s Discretionary Fund (DDF) project, we demonstrated our scanner’s ability to significantly improve the instrument placement capability of the K9 Mars rover. The previous system used stereovision to acquire the terrain information needed to place a test instrument on a feature of interest. The High-Speed 3D Scanner improves on the stereovision technique because it achieves higher resolution without being as sensitive to natural lighting conditions and texture of the target surface. Because of this, the 3D Scanner works in total darkness, on high contrast scenes, and on smooth non-textured surfaces – all areas where traditional stereovision has difficulty.
The two images below compare the output terrain map from the High Speed 3D Scanner (left) and the K9 Mars rover’s stereo-vision system (right) for the same scene.
Inspection of Orbiter TPS
We are currently working to develop two instruments for inspection of the Orbiter Thermal Protection System (including RCC and ceramic tile components). The first system is a portable instrument to be used for defect measurement by Shuttle technicians working on the ground at Kennedy Space Center . This system will be small (5x5x4 inches), lightweight (3lbs), battery powered, and very accurate (0.005 inch). The second system is a candidate for in-flight inspection of Shuttle tiles. This system will use the robotic arm on the Shuttle to scan for defects anywhere between 6 and 20 feet away.
Left: High speed 3D scanner prototype.
The images below show a scan of an 8x8 foot panel of tiles, taken during a test series at JSC. The image to the left is a picture of the target surface, and the image to the right is the corresponding scan from 15.4 feet away. The scan was taken in about 5 seconds. In addition, the scan successfully detects surface defects smaller than 1/4 inch and thus demonstrates the ability to quickly cover large inspection areas while maintaining high-resolution.
In 1996 Ames began researching and developing an accurate electronic inspection method for finding and computing the size of defects on Orbiter tiles. Over the next four years a small hand-held instrument was developed to obtain and archive high-resolution 3D surface maps of tile damage. This instrument was part of the Electronic Imaging and Mapping System (EIMS) delivered to Kennedy Space Center in 2001.
Left: High speed 3D scanner. Right: Stereo vision.
Over the next year the High Speed 3D Scanner was developed as a 2nd generation instrument. It incorporates significant improvements which make it much faster, more reliable, and easier to use. 3D processing is done right on board the instrument in real time, and the resultant 3D files are transmitted over a USB 2.0 connection to a PC. This results in rapid scans with high-resolution 3D images produced while the instrument is scanning.
Left: Tile panel picture. Right: Tile panel scan – 5 second scan time.
The sample scan of a penny and corresponding blow up of the date shown below illustrate the High Speed Scanner’s resolving power and ability to detect fine details. This scan achieves about one-thousandth of an inch resolution in 2 seconds.