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Impact of haptic cues and an active ankle exoskeleton on gait characteristics
Summary
Summary
Objective This study examined the interaction of gait-synchronized vibrotactile cues with an active ankle exoskeleton that provides plantarflexion assistance. Background An exoskeleton that augments gait may support collaboration through feedback to the user about the state of the exoskeleton or characteristics of the task. Methods Participants (N = 16) were...
Large-format Geiger-mode avalanche photodiode arrays and readout circuits
Summary
Summary
Over the past 20 years, we have developed arrays of custom-fabricated silicon and InP Geiger-mode avalanche photodiode arrays, CMOS readout circuits to digitally count or time stamp single-photon detection events, and techniques to integrate these two components to make back-illuminated solid-state image sensors for lidar, optical communications, and passive imaging...
Flexible glucose sensors and fuel cells for bioelectronic implants
Summary
Summary
Microfabrication techniques were developed to create flexible 24 um thick glucose sensors on polyimide substrates. Measurements of the sensor performance, recorded as voltage potential, were carried out for a range of glucose concentrations (0 – 8 mM) in physiological saline (0.1 M NaCl, pH 7.4). The sensors show rapid response...
Covariance estimation in terms of Stokes parameters with application to vector sensor imaging
Summary
Summary
Vector sensor imaging presents a challenging problem in covariance estimation when allowing arbitrarily polarized sources. We propose a Stokes parameter representation of the source covariance matrix which is both qualitatively and computationally convenient. Using this formulation, we adapt the proximal gradient and expectation maximization (EM) algorithms and apply them in...
HF vector sensor for radio astronomy: ground testing results
Summary
Summary
The radio sky below ~10 MHz is largely unexplored due to the inability of ground-based telescopes to observe near or below the ionospheric plasma frequency, or cut-off frequency. A space-based interferometric array is required to probe the portion of the electromagnetic (E-M) spectrum below 10 MHz with sufficient angular resolution...
Liquid crystal uncooled thermal imager development
Summary
Summary
An uncooled thermal imager is being developed based on a liquid crystal (LC) transducer. Without any electrical connections, the LC transducer pixels change the long-wavelength infrared (LWIR) scene directly into a visible image as opposed to an electric signal in microbolometers. The objectives are to develop an imager technology scalable...
Geiger-mode avalanche photodiode arrays integrated to all-digital CMOS circuits
Summary
Summary
This article reviews MIT Lincoln Laboratory's work over the past 20 years to develop photon-sensitive image sensors based on arrays of silicon Geiger-mode avalanche photodiodes. Integration of these detectors to all-digital CMOS readout circuits enable exquisitely sensitive solid-state imagers for lidar, wavefront sensing, and passive imaging.
Silicon Geiger-mode avalanche photodiode arrays for photon-starved imaging
Summary
Summary
Geiger-mode avalanche photodiodes (GMAPDs) are capable of detecting single photons. They can be operated to directly trigger all-digital circuits, so that detection events are digitally counted or time stamped in each pixel. An imager based on an array of GMAPDs therefore has zero readout noise, enabling quantum-limited sensitivity for photon-starved...
Liquid crystal uncooled thermal imager development
Summary
Summary
An uncooled thermal imager is being developed based on a liquid crystal transducer. The liquid crystal transducer changes a long-wavelength infrared scene into a visible image as opposed to an electric signal in microbolometers. This approach has the potential for making a more flexible thermal sensor. One objective is to...
New CCD imagers for adaptive optics wavefront sensors
Summary
Summary
We report on two recently developed charge-coupled devices (CCDs) for adaptive optics wavefront sensing, both designed to provide exceptional sensitivity (low noise and high quantum efficiency) in high-frame-rate low-latency readout applications. The first imager, the CCID75, is a back-illuminated 16-port 160x160 pixel CCD that has been demonstrated to operate at...