Evan Cull

Tracking and imaging humans on heterogeneous infrared sensor arrays for law enforcement applications

We present a plan for the integration of geometric constraints in the source, sensor and analysis levels of sensor networks. The goal of geometric analysis is to reduce the dimensionality and complexity of distributed sensor data analysis so as to achieve real-time recognition and response to significant events. Application scenarios include biometric tracking of individuals, counting and analysis of individuals in groups of humans and distributed sentient environments. We are particularly interested in using this approach to provide networks of low cost point detectors, such as infrared motion detectors, with complex imaging capabilities. By extending the capabilities of simple sensors, we expect to reduce the cost of perimeter and site security applications.

Tomographic imaging of foam

The morphology of three-dimensional foams is of interest to physicists, engineers, and mathematicians. It is desired to image the 3-dimensional structure of the foam. Many different techniques have been used to image the foam, including magnetic resonance imaging, and short-focal length lenses. We use a camera and apply tomographic algorithms to accurately image a set of bubbles. We correct for the distortion of a curved plexiglas container using ray-tracing.

Tracking and imaging humans on heterogeneous infrared sensor arrays for tactical applications

We recently implemented a heterogeneous network of infrared motion detectors and an infrared camera for the detection, localization, tracking, and identification of human targets. The network integrates dense deployments of low cost motion sensors for target tracking with sparse deployments of image sensors for target registration. Such networks can be used in tactical applications for local and distributed perimeter and site security. Rapid deployments for crisis management may be of particular interest. This paper focuses particularly on the need for applications that deal with relatively dense and complex source fields such as crowds move through sensor spaces.

Dispersion multiplexing with broadband filtering for miniature spectrometers.

We replace the traditional grating used in a dispersive spectrometer with a multiplex holographic grating to increase the spectral range sensed by the instrument. The multiplexed grating allows us to measure three different, overlapping spectral bands on a color digital focal plane. The detectors broadband color filters, along with a computational inversion algorithm, let us disambiguate measurements made from the three bands. The overlapping spectral bands allow us to measure a greater spectral bandwidth than a traditional spectrometer with the same sized detector. Additionally, our spectrometer uses a static coded aperture mask in the place of a slit. The aperture mask allows increased light throughput, offsetting the photon loss at the broadband filters. We present our proof-of-concept dispersion multiplexing spectrometer design with experimental measurements to verify its operation.

Standoff raman spectroscopy system for remote chemical detection.

We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operational, rather than optical considerations. In this paper we present the design of our coded-aperture standoff spectroscopy system as well as experimental data collected while making remote measurements.

Information flow in streaming 3D video

We describe streaming 3D video on the Argus sensor space. Argus is a Beowulf-style distributed computer with 64 processors and 64 video camera/capture pairs. Argus is a test-bed for comparing sensor space modeling and reconstruction algorithms. We describe the implementation of tomographic and stereo triangulation algorithms on this space and consider mappings from the sensor space to associated display spaces.

Multimodal optical spectrometers for remote chemical detection.

We have developed a class of aperture coding schemes for Remote Raman Spectrometers (RRS) that remove the traditional trade-off between throughput and spectral resolution. As a result, the size of the remote interrogation region can be driven by operational, rather than optical considerations. We present theoretical arguments on the performance of these codes and present data from where we have utilized these codes in other spectroscopy efforts.

Three dimensional imaging with the argus sensor array

The Argus project uses an array of computers and cameras as a means of investigating telepresence and real-time three-dimensional imaging. In this paper we will briefly discuss telepresence from an information flow and visualization perspective. The paper also includes a detailed description of the Argus hardware and a software layer developed to manage the imaging and computational resources. MPEG-2 and feature extraction will be described as parallel compression systems for the Argus camera array.

Target estimation from interferometric tracking telescopes

Joint target triangulation and estimation from spatio-spectral tracking using a rotational shear interferometer on a telescope is described. The system is based on an array of three eight-inch off-axis parabolic reflector telescopes with CCD cameras used for imaging.