US5448070A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Identification of unknown gases using infrared absorption spectroscopy
Assignee: Thermo Environmental Instruments Inc
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Filing: 1993-05-21
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Granted: 1995-09-05
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Expires: 2013-05-21
Abstract
Abstract A method and apparatus for identifying an unknown gas by generating an infrared spectrum of the unknown gas using an infrared spectrophotometer that includes a circular variable interference filter, compressing the infrared spectrum of the unknown gas, and comparing the compressed infrared spectrum of the unknown gas to a library of compressed infrared spectra of reference compounds. After comparison, the compressed spectra that most closely match the unknown gas are decompressed and displayed. Because frequency characteristics of circular variable interference filters vary from filter to filter, information designating these frequency characteristics for the particular filter employed are used in generating the infrared spectrum of the unknown gas.
Inventors
- 👤 Stephen Day
- 👤 Kailash Swarna
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:37
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01J3/12; G01J2003/1226; G01J2003/1234; G01J2003/283; G01J2003/2833; G01J2003/2866
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
78 words
A method of identifying an unknown gas, comprising the steps of: compressing infrared spectra from a set of infrared spectra of reference compounds to produce a library of compressed infrared spectra of reference compounds, generating an infrared spectrum of said unknown gas using an infrared spectrophotometer that includes a circular variable interference filter, compressing said infrared spectrum of said unknown gas, comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds.
Claim 2
Independent Claim
78 words
A method of identifying an unknown gas, comprising the steps of: compressing infrared spectra from a set of infrared spectra of reference compounds to produce a library of compressed infrared spectra of reference compounds, generating an infrared spectrum of said unknown gas using an infrared spectrophotometer that includes a circular variable interference filter, compressing said infrared spectrum of said unknown gas, comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds.
Claim 3
Dependent Claim
51 words
The method of claim 1, wherein said set of infrared spectra of reference compounds are compressed from infrared spectra obtained using an infrared spectrophotometer that does not include a circular variable interference filter and has higher resolution than said infrared spectrophotometer used in generating said infrared spectrum of said unknown gas.
Claim 4
Dependent Claim
40 words
The method of claim 1, wherein said generating step method further includes generating an infrared spectrum of a background air sample and modifying said infrared spectrum of said unknown gas based on said infrared spectrum of said background air sample.
Claim 5
Dependent Claim
19 words
The method of claim 1, wherein said generating step further includes normalizing said infrared spectrum of said unknown gas.
Claim 6
Dependent Claim
16 words
The method of claim 1, wherein said compressing steps use a compression ratio of about 10:1.
Claim 7
Independent Claim
97 words
A method of identifying an unknown gas, comprising the steps of: compressing infrared spectra from a set of infrared spectra of reference compounds to produce a library of compressed infrared spectra of reference compounds, generating an infrared spectrum of said unknown gas, compressing said infrared spectrum of said unknown gas, comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds, decompressing a plurality of said compressed infrared spectra from said library, said plurality including the compressed infrared spectra that most closely match the compressed infrared spectrum of said unknown gas.
Claim 8
Independent Claim
97 words
A method of identifying an unknown gas, comprising the steps of: compressing infrared spectra from a set of infrared spectra of reference compounds to produce a library of compressed infrared spectra of reference compounds, generating an infrared spectrum of said unknown gas, compressing said infrared spectrum of said unknown gas, comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds, decompressing a plurality of said compressed infrared spectra from said library, said plurality including the compressed infrared spectra that most closely match the compressed infrared spectrum of said unknown gas.
Claim 9
Dependent Claim
20 words
The method of claim 6, wherein said plurality of decompressed infrared spectra comprises the three most closely matching infrared spectra.
Claim 10
Dependent Claim
19 words
The method of claim 6, said method further including the step of displaying said plurality of decompressed infrared spectra.
Claim 11
Dependent Claim
20 words
The method of claim 8, said method further including the step of displaying said infrared spectrum of said unknown gas.
Claim 12
Independent Claim
101 words
An apparatus for identifying an unknown gas, comprising: an infrared spectrophotometer including a circular variable interference filter for producing an infrared spectrum of said unknown gas, circuitry for compressing said infrared spectrum of said unknown gas, a library of compressed infrared spectra of reference compounds compressed from infrared spectra obtained using an infrared spectrophotometer that does not include a circular variable interference filter and has higher resolution than said infrared spectrophotometer used in generating said infrared spectrum of said unknown gas, and circuitry for comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds.
Claim 13
Independent Claim
101 words
An apparatus for identifying an unknown gas, comprising: an infrared spectrophotometer including a circular variable interference filter for producing an infrared spectrum of said unknown gas, circuitry for compressing said infrared spectrum of said unknown gas, a library of compressed infrared spectra of reference compounds compressed from infrared spectra obtained using an infrared spectrophotometer that does not include a circular variable interference filter and has higher resolution than said infrared spectrophotometer used in generating said infrared spectrum of said unknown gas, and circuitry for comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra of reference compounds.
Claim 14
Dependent Claim
13 words
The apparatus of claim 10, wherein said apparatus is battery operated and portable.
Claim 15
Independent Claim
78 words
An apparatus for identifying an unknown gas, comprising: circuitry for compressing an infrared spectrum of said unknown gas, a library of compressed infrared spectra of reference compounds, circuitry for comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra from said library, circuitry for decompressing a plurality of said compressed infrared spectra from said library, said plurality including the compressed infrared spectra that most closely match the compressed infrared spectrum of said unknown gas.
Claim 16
Independent Claim
78 words
An apparatus for identifying an unknown gas, comprising: circuitry for compressing an infrared spectrum of said unknown gas, a library of compressed infrared spectra of reference compounds, circuitry for comparing said compressed infrared spectrum of said unknown gas to said compressed infrared spectra from said library, circuitry for decompressing a plurality of said compressed infrared spectra from said library, said plurality including the compressed infrared spectra that most closely match the compressed infrared spectrum of said unknown gas.
Claim 17
Dependent Claim
18 words
The apparatus of claim 12, said apparatus further including circuitry for displaying said plurality of decompressed infrared spectra.
Claim 18
Dependent Claim
26 words
The apparatus of claim 12, said apparatus further including circuitry for displaying said infrared spectrum of said unknown gas and said plurality of decompressed infrared spectra.
Claim 19
Dependent Claim
13 words
The apparatus of claim 12, wherein said apparatus is battery operated and portable.
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