Jack W. Wood

Covert camera for screening of vehicle interiors and HOV enforcement

This paper describes a covert means of photographing the interiors of moving vehicles at all times of the day or night through clear or tinted windows. The system is called the Georgia Vehicle Occupancy System (GVOS). It utilizes an infrared (IR) strobe light to illuminate passenger and cargo compartments through side windows or the windshield. A high-speed, digital, infrared camera records the images and is capable of providing clear, stop-motion images of the interiors of vehicles moving at highway speeds. A human screener can view these images, or pattern recognition algorithms can be used to count the number of passengers, identify particular individuals, or screen the types and placement of cargo. Examples of vehicle interior images recorded at highway speeds are shown. For homeland security, such a system can be used to screen vehicles entering military bases or other sensitive sites or it can be implemented on highways for identifying and tracking suspicious individuals.

Eye-safe lidar as an undergraduate research experience

Agnes Scott College and the Georgia Institute of Technology are jointly developing an eye safe atmospheric lidar as a unique hands-on research experience for undergraduates, primarily undergraduate women. Students from both institutions will construct the lidar under the supervision of Agnes Scott and Georgia Tech faculty members. The engineering challenges of making lidar accessible and appropriate for undergraduates are described. The project is intended to serve as a model for other schools.

A new type of lidar for atmospheric optical turbulence

We are developing a new type of lidar for measuring range profiles of atmospheric optical turbulence. The lidar is based on a measurement concept that is immune to artifacts caused by effects such as vibration and defocus. Four different types of analysis and experiment have all shown that a turbulence lidar built from commercially-available components will attain a demanding set of performance goals. The lidar is currently being built for testing scheduled in 2007.

Testing of LIDAR system for turbulence profiles

The Georgia Tech Research Institute (GTRI) has developed a new type of LIDAR system for monitoring profiles of atmospheric refractive turbulence. The system makes real-time measurements by projecting a laser beam to form a laser beacon at several successive altitudes. The beacon is observed with a multiple-aperture telescope and the motion of the beacon images from each altitude is characterized as the differential image motion variance. An inversion algorithm has been developed to retrieve the turbulence profile. GTRI built a brassboard version of the LIDAR instrument and tested it in October and December 2007, with truth data from scintillometers and from balloon-borne microthermal probes. The tests resulted in the first time-height diagram of the strength of turbulence ever recorded by a LIDAR.

NEXLASER: an unattended tropospheric aerosol and ozone lidar

This paper describes the development of a laboratory prototype unattended LIDAR system to measure aerosol profiles to 10km and ozone profiles to 3km. One consideration in an unattended system is a robust, eye-safe optical design that can provide the necessary signal levels and dynamic range to produce profiles at required height, resolution, and accuracy. An equally important consideration is a set of algorithms to compute aerosol and ozone profiles under a range of atmospheric conditions. NEXLASER employs an atmospheric state model to help identify and adapt to the varied conditions it must encounter. The signal-to-noise requirements of the algorithms are demonstrated and related back to hardware design. Performance of the system is demonstrated with simulated atmospheric conditions.

Detection of vehicle occupants in HOV lanes: exploration of image sensing for detection of vehicle occupants

One technique to better utilize existing roadway infrastructure is the use of HOV and HOT lanes. Technology to monitor the use of these lanes would assist managers and planners in efficient roadway operation. There are no available occupancy detection systems that perform at acceptable levels of accuracy in permanent field installations. The main goal of this research effort is to assess the possibility of determining passenger use with imaging technology. This is especially challenging because of recent changes in the glass types used by car manufacturers to reduce the solar heat load on the vehicles. We describe in this research a system to use multi-plane imaging with appropriate wavelength selection for sensing passengers in the front and rear seats of vehicles travelling in HOV/HOT lanes. The process of determining the geometric relationships needed, the choice of illumination wavelengths, and the appropriate sensors are described, taking into account driver safety considerations. The paper will also cover the design and implementation of the software for performing the window detection and people counting utilizing both image processing and machine learning techniques. The integration of the final system prototype will be described along with the performance of the system operating at a representative location.

Target edge response

We investigated an edge response of an extended object in a turbulent atmosphere using imagery data acquired with a double-waveband passive imaging system operating in the visible IR wavebands and an actively illuminated optical sensor. We made two findings. We found that the edge response of an extended object is independent of an exposure time, and an atmospheric tilt does not contribute to the image blur of an extended object. In addition, we found that turbulence-induced image blur for an extended object reduces, not increases, with the imager diameter. Therefore, one can reduce the turbulence-induced image blur for an extended object reduces, not increases, with the imager diameter. Therefore, one can reduce the turbulence-induced blur by increasing aperture diameter of an imaging lens. Both findings contradict the predictions of the conventional imaging theory, suggesting that the conventional theory is not applicable to extended anisoplanatic objects. We provided physical interpretation for the results obtained. In addition, we discussed the mitigation techniques that allow us to reduce both turbulence-induced image blur and edge waviness in optical images.