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Patent Number: |
7495767 |
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Case ID: |
0 |
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Patent Title:
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Digital optical method (DOM.TM.) and system for determining opacity
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Status: |
ACTIVE |
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Status Date: |
10/12/2009 7:27:51 AM |
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Issue Date:
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2/24/2009 |
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Filed Date:
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4/20/2006 |
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Serial #:
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1/407,216 |
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Assignee Name:
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United States of America as Represented by the Secretary of the Army
(Washington,
DC)
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Inventor(s):
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Kim, Byung J. , Rood, Mark J. , Du, Ke |
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BACKGROUND
A measurement of opacity is employed in a standard used by the U.S. Environmental Protection Agency (USEPA) for visible emissions. Opacity is defined as the fraction (usually expressed as a percentage) of a light beam, which is in its passage
through a smoke plume (or any other attenuating medium), and is removed from that beam by absorption and/or scattering. P. Lilienfeld et al, Passive Remote Smoke Plume Opacity Sensing: A Technique, Applied Optics, Vol. 20, No. 5, 800-806, 1981. It can
be mathematically defined as 100% minus the percentage of the transmitted light radiance to the initial light radiance. The existing methods for monitoring opacity include Method 9 of the USEPA (USEPA Visual Determination of the Opacity of Emissions
from Stationary Sources, 60 CFR, App. A. (7-1-92 Edition), 849-855, 1992), in-stack transmissometer (Conner, W. D. and H. B. McElhoe, Comparison of Opacity Measurements by Trained Observer and In-Stack Transmissometer, Journal of t . . . . More |
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Photography is employed to objectively quantify opacity of fluids such as
smoke plumes and dust via a method termed the Digital Optical Method
(DOM.TM.). The DOM.TM. quantifies the ratio of radiance values by means
of a camera response curve obtained using objective measures. The
radiance ratios are then used to calculate opacity of target fluids such
as smoke plumes. The DOM.TM. quantifies opacity during both daytime and
nighttime conditions with a much broader range of subject types, e.g.,
white, gray and black smoke plumes, and environmental conditions, e.g.,
non-blue-sky, building, and mountain backgrounds, than existing systems
while not requiring human interpretation for any application. In one
embodiment, the DOM.TM. quantifies opacity from digital photos using a
pre-designed algorithm and an inexpensive digital camera. Very little
training is needed to implement the DOM.TM. and it yields consistent
objective quant . . . . More |
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We claim:
1. A method for obtaining an accurate quantitative measure of the opacity of a fluid, comprising: providing at least one image receiving device incorporating at least one light
sensitive device; calibrating said image receiving devices, wherein said calibrating yields at least one response curve for each said image receiving devices, said response curve empirically based on a ratio of received radiances; employing at least
one said image receiving device for taking images of said fluid, said images to include at least one background associated with said fluid; providing at least one algorithm based on a ratio of received radiances, said algorithm implemented in software
on a computer readable medium; providing at least one processor for at least running said software; receiving and processing said image on at least one said processor; and analyzing said image using said algorithm and said software to obtain said
measure of opacity, wherein said opacity may be m . . . . More |
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