Entity

Time filter

Source Type

Malibu, CA, United States

Wang S.,HRL Labs LLC | Verbrugge M.,General Motors | Vu L.,HRL Labs LLC | Baker D.,General Motors | Wang J.S.,HRL Labs LLC
Journal of the Electrochemical Society | Year: 2013

We have developed a battery state estimator based on a finite impulse response filter. Simulation results indicate that the estimator gives accurate prediction and numerically-stable performance in the regression of filter coefficients and the open-circuit potential, which yields the battery state of charge. The estimator is also able to predict battery power capabilities. Comparison of the measured and predicted state of charge (SOC) and the charge and discharge power capabilities (state of power, SOP) of a Li-ion battery are provided. Predictions for the SOC and SOP agree well with experimental measurements, demonstrating the estimator's application in battery management systems. In particular, this new approach appears to be more flexible than previous models; we show that it can capture the behavior of batteries governed by various physicochemical phenomena. © 2013 The Electrochemical Society. Source


Mundhenk T.N.,HRL Labs LLC | Baron J.,HRL Labs LLC | Matic R.M.,HRL Labs LLC
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Passive millimeter wavelength (PMMW) video holds great promise given its ability to see targets and obstacles through fog, smoke and rain. However, current imagers produce undesirable complex noise. This can come as a mixture of fast shot (snow like) noise and a slower forming circular fixed pattern. Shot noise can be removed by a simple gain style filter. However, this can produce blurring of objects in the scene. To alleviate this, we measure the amount of Bayesian surprise in videos. Bayesian surprise is feature change in time which is abrupt, but cannot be accounted for as shot noise. Surprise is used to attenuate the shot noise filter in locations of high surprise. Since high Bayesian surprise in videos is very salient to observers, this reduces blurring particularly in places where people visually attend. Fixed pattern noise is removed after the shot noise using a combination of Non-uniformity correction (NUC) and Eigen Image Wavelet Transformation. The combination allows for online removal of time varying fixed pattern noise even when background motion may be absent. It also allows for online adaptation to differing intensities of fixed pattern noise. The fixed pattern and shot noise filters are all efficient allowing for real time video processing of PMMW video. We show several examples of PMMW video with complex noise that is much cleaner as a result of the noise removal. Processed video clearly shows cars, houses, trees and utility poles at 20 frames per second. © 2011 SPIE. Source


Wang J.S.,HRL Labs LLC | Liu P.,HRL Labs LLC | Soukiazian S.,HRL Labs LLC | Tataria H.,General Motors | And 4 more authors.
Journal of Power Sources | Year: 2014

Start-stop systems require the battery to provide high power, endure shallow cycling, and exhibit long cycle life. The LFP/LTO (lithium iron phosphate/lithium titanate) battery is a potential candidate to meet such requirements because, at room temperature, both materials can be operated at high rate and have good stability (calendar and cycle life). In this work, we have investigated the feasibility of using LixFePO 4/Li4+3yTi5O12 (0 < x < 1, 0 < y < 1) lithium ion batteries for start-stop systems. We evaluate both the rate and temperature dependence of LFP/LTO cells subjected to galvanostatic charge/discharge cycling. Excellent rate performance was observed at temperatures above or at ambient. However, at low temperatures, significant resistance is observed, and this must be addressed for the LFP/LTO system to be viable. In addition, we investigate the SOC dependence of equivalent circuit parameters using triangular current and voltage excitation method to facilitate the implementation of circuit-based control algorithms for vehicle applications. Parameter values are nearly constant over the broad voltage-plateau region of the substantially two-phase behavior of both the LFP and LTO materials. © 2014 Published by Elsevier B.V. Source


Mundhenk T.N.,HRL Labs LLC | Baron J.,HRL Labs LLC | Matic R.M.,HRL Labs LLC
Optical Engineering | Year: 2012

Passive millimeter wavelength (PMMW) video holds great promise, given its ability to see targets and obstacles through fog, smoke, and rain. However, current imagers produce undesirable complex noise. This can come as a mixture of fast shot (snowlike) noise and a slower-forming circular fixed pattern. Shot noise can be removed by a simple gain style filter. However, this can produce blurring of objects in the scene. To alleviate this, we measure the amount of Bayesian surprise in videos. Bayesian surprise measures feature change in time that is abrupt but cannot be accounted for as shot noise. Surprise is used to attenuate the shot noise filter in locations of high surprise. Since high Bayesian surprise in videos is very salient to observers, this reduces blurring, particularly in places where people visually attend. Fixed pattern noise is removed after the shot noise using a combination of nonuniformity correction and mean image wavelet transformation. The combination allows for online removal of time-varying fixed pattern noise, even when background motion may be absent. It also allows for online adaptation to differing intensities of fixed pattern noise. We also discuss a method for sharpening frames using deconvolution. The fixed pattern and shot noise filters are all efficient, which allows real time video processing of PMMW video. We show several examples of PMMW video with complex noise that is much cleaner as a result of the noise removal. Processed video clearly shows cars, houses, trees, and utility poles at 20 frames per second. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). Source


Wood B.M.,Louisiana State University | Ham K.,Louisiana State University | Hussey D.S.,U.S. National Institute of Standards and Technology | Jacobson D.L.,U.S. National Institute of Standards and Technology | And 6 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2014

The uptake of hydrogen by lanthanum pentanickel (LaNi5) to form lanthanum nickel hydride (LaNi5H6) is followed with three-dimensional imaging by neutron tomography. The hydrogen absorption process is slower than the time needed for acquiring a single radiograph, about 10 s, but fast relative to the time to acquire a fully-sampled tomographic data set, about 6000 s. A novel data acquisition scheme is used with angles based upon the Greek Golden ratio, a scheme which allows considerable flexibility in post-acquisition tomography reconstruction. Even with tomographic undersampling, the granular structure for the conversion of LaNi5 particles to LaNi5H6 particles is observed and visually tracked in 3D. Over the course of five sequential hydrogen uptake runs with various initial hydrogen pressures, some grains are repeatedly observed. © 2014 Elsevier B.V. All rights reserved. Source

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