WO1994002839A1 - Procede pour analyser le contenu de recipients - Google Patents

Procede pour analyser le contenu de recipients Download PDF

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Publication number
WO1994002839A1
WO1994002839A1 PCT/US1993/006659 US9306659W WO9402839A1 WO 1994002839 A1 WO1994002839 A1 WO 1994002839A1 US 9306659 W US9306659 W US 9306659W WO 9402839 A1 WO9402839 A1 WO 9402839A1
Authority
WO
WIPO (PCT)
Prior art keywords
container
image
contents
images
obtaining
Prior art date
Application number
PCT/US1993/006659
Other languages
English (en)
Inventor
John Steven Steude
Edwin Lockwood Strickland, Iii
Original Assignee
Scientific Measurement Systems, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/916,512 external-priority patent/US5195860A/en
Priority claimed from US08/059,018 external-priority patent/US5400381A/en
Application filed by Scientific Measurement Systems, Inc. filed Critical Scientific Measurement Systems, Inc.
Publication of WO1994002839A1 publication Critical patent/WO1994002839A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/284—Electromagnetic waves
    • G01F23/288—X-rays; Gamma rays or other forms of ionising radiation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
    • G01N23/083—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption the radiation being X-rays
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/06—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption
    • G01N23/10—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and measuring the absorption the material being confined in a container, e.g. in a luggage X-ray scanners
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/419—Imaging computed tomograph

Definitions

  • This invention relates to a process for analyzing the contents of containers.
  • NDE non-destructive evaluation
  • RTR imaging depends on X-ray attenuation measurements. RTR utilizes screen scintillators and image intensifiers for its measurements. Because RTR produces an image of a portion of drum in fractions of a second, moving fluids are visualized as they slosh in their container while the drum is rotated. The average time required by RTR to inspect an entire drum is ten minutes. It has been reported that RTR can detect as little as one teaspoon of water in a drum.
  • RTR Some major disadvantages of RTR are: (1) containers that are full of liquids are not detectable because the liquids do not slosh, (2) the limited dynamic range of screen scintillators and image intensifiers (typically less than 100 intensity levels) have such limited contrast resolution that it is not possible to resolve common materials (i.e., plastics, glass, and metals) in the same image, (3) quantitative measurements of densities, atomic numbers, free liquid volumes, drum wall thickness, etc., are not possible, and (4) RTR systems have only been equipped with 420 kV X-ray tubes which will not penetrate drums filled with cement, sludge, or other dense waste forms.
  • the process for analyzing the contents of containers of the present invention includes obtaining a first image of the contents of a container. Next, the container is tilted and a second image of the contents of the container in the tilted position is obtained. Next, the first and second images are overlaid and, finally, the images are compared one with the other so that contents that have remained horizontal during tilting, i.e., free liquid surfaces, are identified.
  • the steps of obtaining a first and second image are accomplished by use of a digital radiography device.
  • the digital radiograph of the contents is then used for overlaying and subtraction purposes.
  • the digital radiograph scanner of the present invention includes an X-ray source and a detector.
  • the step of tilting includes tilting the container relative to the source and detector units of the scanner.
  • the latter can be accomplished by an automatic tilt table, manually with blocks, etc.
  • the step of tilting the container includes tilting the scanner and the container together.
  • the step of overlaying the first and second images is done digitally with computer software so that the two images are superimposed one over the other. This forces a horizontal surface pictured in the first image to become tilted relative to the horizontal surfaces that remained horizontal after being tilted, as shown by the second image.
  • the step of comparing the first image with the second can be accomplished by means of a variety of mathematical tools including, subtracting, multiplying, adding, and dividing. The comparison is done pixel by pixel or in any manner sufficient to accurately reveal shifting.
  • the process can further include in combination the use of a computed tomography (CT) imaging device for obtaining quantitative measurements of the contents in the drum and of the drum itself.
  • CT computed tomography
  • Such quantitative measurements include shapes, densities, atomic numbers, wall thicknesses, and the like.
  • the supplementary CT measurements augment the ability to detect other unacceptable waste forms such as powders, pressurized containers, etc.
  • FIGURE 1 is a front view illustration of an image of a container within which is located another container with free liquid;
  • FIGURE 2 is a front view of an image of the container of FIGURE 1 shown in a tilted position in accordance with the process of the present invention showing the movement of the liquid in solid lines to remain horizontal and the dotted lines showing the forced tilted position of the fluid of FIGURE 1 on top of FIGURE 2.
  • FIGURE 1 is an illustration of a container 10 within which is located a receptacle 12 containing free liquid 14.
  • free liquid's 14 surface 16 assumes a horizontal position due to gravity.
  • the process of the present invention includes tilting container 10 as illustrated by arrow 18.
  • the free liquid 14 maintains its horizontal position as shown by the surface 16'.
  • DR/CT scanner digital radiography and computed tomography, respectively.
  • the basic components of a DR/CT scanner are: (1) penetrating X- or gamma-ray source, (2) detector unit, (3) object handling unit, and (4) a computer for image processing.
  • Computer hardware and software capable of accomplishing the overlay and substraction step are known in the art and not disclosed further hereafter.
  • An example of such a scanner is a model number 201 DR/CT manufactured by Scientific Measurement Systems, Inc. of Austin, Texas (SMS).
  • SMS Model 201 is designed for large aerospace and automotive components up to six feet in size and weighing up to 2,000 pounds.
  • the DR/CT scanner of the present invention is specifically designed for drum inspection and has scan times of less than one minute per image.
  • the scanner can also be a portable system designed for use in the field under harsh conditions. Speed enhancement is acquired by adding additional detectors that are more closely spaced and by shortening the distance between the scanner source and detectors.
  • a container to be analyzed is placed on the scanner and a digital radiograph of the container is taken.
  • the single radiograph By means of the single radiograph, it is often possible to distinguish containers with liquids from those with powders due to the fact that liquids have smooth horizontal surfaces while powders have rough, irregular surfaces.
  • the single digital radiograph reveals the identity of many items in a drum, it cannot by itself identify free liquid in a conclusive manner. This is possible, however, by means of the process of the present invention including the steps of taking a first radiograph image of the drum, tilting the drum a few degrees, taking a second radiograph of the drum in the tilted position, and digitally overlaying and subtracting one radiograph from the other by means of computer software known in the art.
  • the method of tilting the container consists of manually or mechanically moving the container itself from an upright position on the scanner to a tilted position. This is a simple and effective means of producing the required movement necessary to force the liquid to move relative to their containers so that the property identifying signature may be obtained from whatever liquid is present.
  • Another preferred embodiment eliminates the problem of parallaxing that occurs by means of use of the first tilting method. Because of the geometric relationship of the X-ray source, container, and detectors, the movement of the container results in the movement of the contents of the container and results in a parallax view when the images are compared so that the images aren't totally removed from those items which have actually remained stationary during the tilt. However, by means of tilting the entire scanner and drum for the second image, it is possible to remove the whole image of the stationary items for the reason that the problem of parallaxing has been circumvented.
  • a major advantage of the process of the present invention is that because of the distinct indication, a black and white bar or mirror image triangles associated with shifted liquid surfaces, hquid levels are detectable in containers that have overlapping images due to their position in the drum with respect to the viewing angle.
  • the invention is extremely sensitive in that it has been possible to identify the black and white signal associated with the shifting of as little as 1.0 and 2.5 milliliters of water.
  • CT images can be obtained in scanning times on the order of one minute and would be used in a variety of situations, when it is necessary to further characterize the contents of the drum or the characteristics of the drum itself. For example, a CT image can be taken where there is an indication of a puncture hole in an aerosol can, as required, for disposal, but a CT scan is needed to confirm the presence of the hole.
  • a single CT image represents a precise two-dimensional map of density that is independent of the shapes and locations of objects of interest. Multiple CT images can be used to obtain precise 3-dimensional density maps.
  • the sensitivity of CT measurements to slight changes in density is typically orders of magmtude better than that obtainable with radiography.
  • Atomic number maps are obtained by scanning objects with a high and low X- ray energy and processing the data to extract the X-ray attenuation due to atomic number from that due to density.
  • a CT image can also be used to measure drum wall thickness because it is a spatially resolved map of density.
  • Image analysis software used in the art provides the ability to draw a line on an image. The software plots the density along that line to display a density profile. The height and width of a spike in the density at the drum wall is directly proportional to the drum wall thickness. With calibration, the density profiles across the drum wall can measure drum wall thickness to an accuracy on the order of 0.001 inch. This analysis process can be automated to find the thinnest portion of drum wall.
  • the time required to measure the thinnest wall around the drum circumference at eight heights on the drum wall is approximately eight minutes. Further, the eight CT images are used to inspect the waste inside the drum.
  • ultrasound takes three to four times longer for the same wall thickness measurements and does not provide any information on the drum contents. Furthermore, measurements by the present invention will work on rusty drum surfaces while ultrasound measurements will not.
  • the process of the present invention enables rapid detection of small amounts of free liquids in drums with miscellaneous contents.
  • the digital radiographic technique of the present invention depends on the shifting of liquids relative to their containers when a drum is tilted. Titled and non-tilted drum images are overlaid and the difference between them identifies liquid surfaces with a conclusive indicator, such as a black and white signature.
  • CT inspection techniques can provide estimates of volumes of liquids in their containers and identify small amounts of free liquids in dense forms of waste. Still further, the CT/DR combination enables drum wall thickness measurements where prior art devices presently are ineffective.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • General Health & Medical Sciences (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Electromagnetism (AREA)
  • Fluid Mechanics (AREA)
  • Thermal Sciences (AREA)
  • Toxicology (AREA)
  • Theoretical Computer Science (AREA)
  • Radiology & Medical Imaging (AREA)
  • Pulmonology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Engineering & Computer Science (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

L'invention se rapporte à un procédé pour analyser le contenu de récipients, qui consiste à obtenir une première image du récipient (10), à incliner le récipient, à obtenir une seconde image du contenu du récipient dans la position inclinée, à superposer les deux images et à soustraire une image de l'autre, pour que le contenu qui reste à l'horizontale soit identifié et pour que les objets qui s'inclinent soient pour la plupart effacés du champ visuel dans l'image finale résultant de la soustraction. Dans un premier procédé décrit, le récipient (10) est déplacé manuellement ou mécaniquement par rapport au dispositif de prise d'images, constitué par exemple par un dispositif de radiographie numérique. Dans un deuxième procédé décrit, pour éviter les problèmes de parallaxe, le récipient et le dispositif de prise d'images sont déplacés ensemble. On peut utiliser en combinaison avec ces procédés la technique de la tomographie par ordinateur pour obtenir une meilleure caractérisation du contenu, en ce qui concerne les formes, les densités, les numéros atomiques, les épaisseurs de parois et similaires.
PCT/US1993/006659 1992-07-20 1993-07-14 Procede pour analyser le contenu de recipients WO1994002839A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US07/916,512 US5195860A (en) 1992-07-20 1992-07-20 Push-on type fastener for automatic feed and installation equipment
US07/916,512 1992-07-20
US08/059,018 US5400381A (en) 1992-07-20 1993-05-06 Process for analyzing the contents of containers
US08/059,018 1993-05-06

Publications (1)

Publication Number Publication Date
WO1994002839A1 true WO1994002839A1 (fr) 1994-02-03

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Application Number Title Priority Date Filing Date
PCT/US1993/006659 WO1994002839A1 (fr) 1992-07-20 1993-07-14 Procede pour analyser le contenu de recipients

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WO (1) WO1994002839A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2420683A (en) * 2004-11-26 2006-05-31 Univ Tsinghua A CT Method And Apparatus For Identifying A Liquid Article Based On The Density Of The Liquid Article
GB2453641A (en) * 2007-10-05 2009-04-15 Univ Tsinghua Security inspection of liquid articles with dual energy CT imaging
GB2453642A (en) * 2007-10-05 2009-04-15 Univ Tsinghua Security inspection of liquid articles with dual energy CT imaging
WO2010055900A1 (fr) 2008-11-14 2010-05-20 ディナベック株式会社 Procédé de fabrication de cellules dendritiques
US7991112B2 (en) 2007-12-27 2011-08-02 Nuctech Company Limited Article detection apparatus and a detecting method
GB2595215A (en) * 2020-05-15 2021-11-24 Smiths Detection France S A S Detection of liquid

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5056124A (en) * 1989-05-24 1991-10-08 Meiji Milk Products Co., Ltd. Method of and apparatus for examining objects in containers in non-destructive manner

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5056124A (en) * 1989-05-24 1991-10-08 Meiji Milk Products Co., Ltd. Method of and apparatus for examining objects in containers in non-destructive manner

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2420683A (en) * 2004-11-26 2006-05-31 Univ Tsinghua A CT Method And Apparatus For Identifying A Liquid Article Based On The Density Of The Liquid Article
GB2420683B (en) * 2004-11-26 2009-03-18 Univ Tsinghua A computer tomography method and apparatus for identifying a liquid article based on the density of the liquid article
US7508908B2 (en) 2004-11-26 2009-03-24 Tsinghua University CT method and apparatus for liquid safety-detection with a radiation source
US8320523B2 (en) 2007-10-05 2012-11-27 Tshinghua University Method and device for inspection of liquid articles
GB2453642A (en) * 2007-10-05 2009-04-15 Univ Tsinghua Security inspection of liquid articles with dual energy CT imaging
AU2008229696B2 (en) * 2007-10-05 2011-05-12 Nuctech Company Limited Method and device for inspection of liquid articles
US7945017B2 (en) 2007-10-05 2011-05-17 Tsinghua University Method and device for inspection of liquid articles
GB2453642B (en) * 2007-10-05 2011-08-24 Univ Tsinghua Method and device for inspection of liquid articles
GB2453641B (en) * 2007-10-05 2011-08-31 Univ Tsinghua Method and device for inspection of liquid articles
US8036337B2 (en) 2007-10-05 2011-10-11 Tsinghua University Method and device for inspection of liquid articles
GB2453641A (en) * 2007-10-05 2009-04-15 Univ Tsinghua Security inspection of liquid articles with dual energy CT imaging
US8494114B2 (en) 2007-10-05 2013-07-23 Tsinghua University Method and device for inspection of liquid articles
US9121811B2 (en) 2007-10-05 2015-09-01 Tsinghua University Method and device for inspection of liquid articles
US7991112B2 (en) 2007-12-27 2011-08-02 Nuctech Company Limited Article detection apparatus and a detecting method
WO2010055900A1 (fr) 2008-11-14 2010-05-20 ディナベック株式会社 Procédé de fabrication de cellules dendritiques
GB2595215A (en) * 2020-05-15 2021-11-24 Smiths Detection France S A S Detection of liquid

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