AUTOFOCUS is a computer program for use in a control system that automatically adjusts the position of an instrument arm that carries a microscope equipped with an electronic camera.
In the original intended application of AUTOFOCUS, the imaging microscope would be carried by an exploratory robotic vehicle on a remote planet, but AUTOFOCUS could also be adapted to similar applications on Earth. Initially control software other than AUTOFOCUS brings the microscope to a position above a target to be imaged. Then the instrument arm is moved to lower the microscope toward the target: nominally, the target is approached from a starting distance of 3 cm in 10 steps of 3 mm each. After each step, the image in the camera is subjected to a wavelet transform, which is used to evaluate the texture in the image at multiple scales to determine whether and by how much the microscope is approaching focus. A focus measure is derived from the transform and used to guide the arm to bring the microscope to the focal height. When the analysis reveals that the microscope is in focus, image data are recorded and transmitted.
This program was written by Terrance Huntsberger of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Software category.
This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (818) 393-2827. Refer to NPO-30531.
This Brief includes a Technical Support Package (TSP).
Automatic Focus Adjustment of a Microscope
(reference NPO-30531) is currently available for download from the TSP library.
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Overview
The document presents research conducted at NASA's Jet Propulsion Laboratory (JPL) on enhancing rover autonomy for planetary surface operations, specifically focusing on the Field Integrated, Design and Operations (FIDO) rover. FIDO serves as a terrestrial analog for the Mars Exploration Rovers (MER) set to launch in 2003. The paper discusses the integration of advanced sensing technologies and onboard planning capabilities to improve rover autonomy, which is crucial for maximizing scientific data collection while minimizing the need for ground control interactions.
FIDO is equipped with a variety of sensors, including an inertial navigation unit (INU), sun sensors, imagery from mast and body-mounted cameras, and wheel encoders. The research employs multisensor fusion techniques, particularly using an Extended Kalman Filter (EKF) approach, combined with pattern recognition and tracking algorithms. These innovations enable the rover to navigate autonomously, addressing key challenges such as long-distance navigation, precision rendezvous with targets, and the autonomous deployment of scientific instruments.
The document outlines the traditional sense/plan/act strategy for rover navigation, which often requires significant computational resources and time delays. In contrast, JPL's research has shifted towards reactive methods that allow for more efficient navigation, although these methods can encounter issues like deadlock without long-range path planning.
The paper also discusses the long-range rendezvous capabilities of the rover, particularly in the context of the Mars Sample Return (MSR) mission planned for 2013. The rover must navigate autonomously to remote sites, collect samples, and return to the lander. The navigation precision required varies with distance, necessitating different strategies for long-range, mid-range, and short-range traverses. The document details a three-phase sequence for lander acquisition, utilizing feature recognition techniques to enhance the rover's ability to identify man-made structures from various distances.
Overall, the research highlights the importance of developing robust algorithms and technologies for rover autonomy, which are essential for the success of future Mars missions. The findings from the FIDO rover trials in diverse terrestrial environments provide valuable insights that can be applied to enhance the capabilities of rovers in extraterrestrial exploration.
