Bernard S. Fritz

Automatic detection of vehicle occupants: the imaging problem and its solution

Abstract. The automatic detection and counting of vehicle occupants is a challenging research problem that was given little attention until recently. An automated vehicle-occupant-counting system would greatly facilitate the operation of freeway lanes reserved for car pools (high occupancy vehicle lanes or HOV lanes). There are three major aspects of this problem: (a) the imaging aspect (sensor phenomenology), (b) the pattern recognition aspect, and (c) the system architecture aspect. In this paper, we present a solution to the imaging aspect of the problem. We propose a novel system based on fusion of near-infrared imaging signals and we demonstrate its adequacy with theoretical and experimental arguments. We also compare our solution to other possible solutions across the electromagnetic spectrum, particularly in the thermal infrared and visible regions.

A near-infrared fusion scheme for automatic detection of vehicle passengers

We undertook a study to determine if the automatic detection and counting of vehicle passengers is feasible. An automated passenger counting system would greatly facilitate the operation of freeway lanes reserved for car-pools (HOV lanes). In the present paper we report our findings regarding the appropriate sensor phenomenology and arrangement for the task. We propose a novel system based on fusion of near-infrared imaging signals and we demonstrate its adequacy with theoretical and experimental arguments.

Enabling Technologies for a Personal Flow Cytometer (Part I)

The paper reports on three key technologies that have enabled the development of a wearable flow cytometer: flow sensing and control based on low-power MEMS-based sensors/actuators; microfluidic processing based on miniaturized disposable plastic cartridges; and optical detection based on arrays of solid-state lasers/detectors and integrated micro-optics. This instrument can provide early detection of viral and bacterial infections based on quick (30 seconds) measurement of lymphocyte and neutrophil counts [1]. Personnel with little or no medical training can use this low-cost, low-maintenance instrument in doctor’s offices, homes, and public/private-sector facilities. Multiparameter scattering-based or fluorescence-based cytometers can be developed based on this technology for clinical, industrial and military applications.

Automatic detection of vehicle passengers through near-infrared fusion

We undertook a study to determine if the automatic detection and counting of vehicle passengers is feasible. An automated passenger counting system would greatly facilitate the operation of freeway lanes reserved for buses, car-pools, and emergency vehicles (HOV lanes). In the present paper we report our findings regarding the appropriate sensor phenomenology and arrangement for the task. We propose a novel system based on fusion of near-infrared imaging signals and we demonstrate its adequacy with theoretical and experimental arguments.

Replicated hybrid optics in durable materials: test results

We have designed, fabricated, and tested hybrid refractive/diffractive optical elements in acrylic and cyclic olefin copolymer polymers. The elements were tested for optical performance before and after various environmental conditions.

Process-dependent kinoform performance

Results are presented of an on-going experimental program to characterize the effects of processing errors on kinoform performance. Diffraction efficiency and modulation transfer function data are given for various types of processing errors present in staircase kinoforms of a f/10 Fresnel phase lens having two and four levels. Processing errors include etch depth, linewidth, and mask alignment. Processing errors, especially mask alignment, are shown to have the greatest impact on diffraction efficiency and very little effect on image quality.

Tunable hybrid spectral imaging optic: experimental results

An optical device is presented that uses the highly wavelength dispersive nature of diffractive optics to provide a means of either removing a small waveband of incident radiation from a scene, to function as a tunable notch filter, or passing only a small waveband of incident radiation from the scene, to function as a tunable bandpass filter. A prototype design example is presented along with preliminary performance analysis.

Tunable diffractive optical filter for multispectral imaging

An optical device is presented that uses the highly wavelength dispersive nature of diffractive optics to provide a means of either removing a small waveband of incident radiation from a scene, to function as a tunable notch filter, or passing only a small waveband of incident radiation from the scene, to function as a tunable bandpass filter. Design examples are given along with system performance analysis. Experimental verification is also presented.