Abstract: An autonomous pavement assessment system may receive depth data indicative of the depth of pixels that collectively comprise multiple defective areas of pavement. For each defective area, the system may fit a plane to it; generate a histogram that indicates the frequency of its pixels at different depths; dynamically determine a depth noise threshold for it; generate a binary image of it based on its noise threshold; and generate a depth map of it containing only the pixels that have a depth that meets or exceeds its depth noise threshold. The system may prioritize the multiple defective areas for repair and/or generate optimized rehabilitation routes. Crowd sourcing may be used to gather the depth data, as well as location information for each defective area.

Abstract: Contact-less remote-sensing crack detection and/quantification methodologies are described, which are based on three-dimensional (3D) scene reconstruction, image processing, and pattern recognition. The systems and methodologies can utilize depth perception for detecting and/or quantifying cracks. These methodologies can provide the ability to analyze images captured from any distance and using any focal length or resolution. This adaptive feature may be especially useful for incorporation into mobile systems, such as unmanned aerial vehicles (UAV) or mobile autonomous or semi-autonomous robotic systems such as wheel-based or track-based radio controlled robots, as utilizing such structural inspection methods onto those mobile platforms may allow inaccessible regions to be properly inspected for cracks.

Abstract: Stress to a flexible structure in a dynamic environment is suppressed by controlling at least one variable parameter of an associated damper in accordance with sensed information as to movement of the structure. In a preferred embodiment, the damper is an impact damper having an auxiliary mass mounted for movement within a variable clearance permitting the timing of impacts to be controlled. In either case, impacts between the auxiliary mass and the flexible structure occur substantially when the flexible structure passes through a preselected neutral position, at which the velocity of the structure is a maximum.

Abstract: A method and apparatus for active control of flexible structures subjected to shocks such as earthquake ground motion. In a first embodiment, the deflection of the structure beyond a prescribed threshold triggers a corrective pulse of mechanical energy which is applied within one period of the structure's lowest mode of vibration. The pulse serves to disorganize the buildup of harmonic motion. In a second embodiment, a pulse, calculated at each deflection cross-over point (during vibration), is applied to the structure in a direction opposite to that of its instantaneous velocity to effect active damping of the motion.