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— This paper describes a data set collected by an autonomous ground vehicle testbed, based upon a modified Ford F-250 pickup truck. The vehicle is outfitted with a professional (Applanix POS-LV) and consumer (Xsens MTi-G) inertial measurement unit (IMU), a Velodyne 3D-lidar scanner, two push-broom forward looking Riegl lidars, and a Point Grey Ladybug3(More)
This paper reports on a mutual information (MI) based algorithm for automatic extrinsic calibration of a 3D laser scanner and optical camera system. By using MI as the registration criterion, our method is able to work in situ without the need for any specific calibration targets, which makes it practical for in-field calibration. The calibration parameters(More)
This paper reports on various aspects of the Intelligent Vehicle Systems (IVS) team's involvement in the recent 2007 DARPA Urban Challenge, wherein our platform, the autonomous " XAV-250, " competed as one of the 11 finalists qualifying for the event. We provide a candid discussion of the hardware and software design process that led to our team's entry,(More)
— This paper reports a novel algorithm for boot-strapping the automatic registration of unstructured 3D point clouds collected using co-registered 3D lidar and omnidirec-tional camera imagery. Here, we exploit the co-registration of the 3D point cloud with the available camera imagery to associate high dimensional feature descriptors such as scale invariant(More)
Magic-sized cadmium selenide (CdSe) nanocrystals have been pyrolytically synthesized. These ultra-small nanocrystals exhibit broadband emission (420-710 nm) that covers most of the visible spectrum while not suffering from self absorption. This behavior is a direct result of the extremely narrow size distribution and unusually large Stokes shift (40-50 nm).(More)
— This paper reports a novel mutual information (MI) based algorithm for automatic registration of unstructured 3D point clouds comprised of co-registered 3D lidar and camera imagery. The proposed method provides a robust and principled framework for fusing the complementary information obtained from these two different sensing modalities. High-dimensional(More)
This paper reports on an algorithm for automatic, targetless, extrinsic calibration of a li-dar and optical camera system based upon the maximization of mutual information between the sensor measured surface intensities. The proposed method is completely data driven and does not require any fiducial calibration targets—making in situ calibration easy. We(More)
— This paper reports on a method for tracking a camera system within an a priori known map constructed from co-registered 3D light detection and ranging (LIDAR) and omnidirectional image data. Our method pre-processes the raw 3D LIDAR and camera data to produce a sparse map that can scale to city-size environments. From the original LIDAR and camera data we(More)
Individual ultrasmall CdSe nanocrystals have recently been found to emit white light, but the ultimate origin of the phenomenon has remained elusive. Here we use a combination of state-of-the-art experiment and theory to show that excitation sets the ultrasmall nanocrystals into a fluxional state. Their energy gaps vary continuously on a femtosecond time(More)
Physical variations in colloidal nanostructures give rise to heterogeneity in expressed optical behavior. This correlation between nanoscale structure and function demands interrogation of both atomic structure and photophysics at the level of single nanostructures to be fully understood. Herein, by conducting detailed analyses of fine atomic structure,(More)