Apparatus and method for multi-spectral dual balanced imaging

• US 9,638,846 B2
• Filed: 07/12/2012
• Issued: 05/02/2017
• Est. Priority Date: 07/20/2011
• Status: Expired due to Fees

• Current Assignee: Power Diagnostic Technologies Ltd.
• Original Assignee: Power Diagnostic Technologies Ltd.
• Inventors: Parsons, Robert
• Primary Examiner(s): Haskins, Twyler
• Assistant Examiner(s): Trehan, Akshay
• Application Number:
  US14/233,358
• Publication Number:
  US 20140354873A1
• Time in Patent Office: 1,755 Days
• CPC Class Codes: G01J 3/0208 using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
• CPC Class Codes: G01J 3/0227 using notch filters
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G02B 27/1013 for colour or multispectral image sensors, e.g. splitting an image into monochromatic image components on respective sensors spectral imaging systems G01J
• CPC Class Codes: G02B 5/26 Reflecting filters G02B5/28 takes precedence
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 25/671 for non-uniformity detection or correction

Abstract

An apparatus and method for multi-spectral dual balanced imaging is provided. The apparatus includes: (a) a first member operable to produce from incident light a first band having first band wavelengths and a second band; and (b) a second member operable to produce from the second band a third band having wavelengths shorter than the first band wavelengths, excluding the first band wavelengths and having wavelengths longer than the first band wavelengths. The method involves: (a) producing from incident light a first band having first band wavelengths and a second band; and (b) producing from the second band a third band having wavelengths shorter than the first band wavelengths, excluding the first band wavelengths and having wavelengths longer than the first band wavelengths.

Claims

1. An apparatus for multi-spectral balanced imaging, the apparatus comprising:

(a) a notch filter operable to produce from incident light a first band having first band wavelengths and a second band;

(b) a band reflection filter positioned to receive said second band from said notch filter, said band reflection filter being operable to produce from said second band a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths, said band reflection filter having its center substantially coinciding with the center of said notch filter;

(c) a first detector for producing a first image by detecting said first band; and

(d) a second detector for producing a second image by detecting said third band after said third band has propagated from said band reflection filter through said notch filter to said second detector,

wherein said notch filter and said band reflection filter are selected such that a first intensity associated with said first band is substantially equal to a second intensity associated with said third band when said incident light is uniform.

2. The apparatus of claim 1 wherein the apparatus is operable to determine from said first and second images a flow rate associated with a gas plume.

3. The apparatus of claim 1 further comprising an entry mirror, the apparatus being operable to permit said notch filter and said band reflection filter to rotate in a first direction and said entry mirror to rotate in a second direction opposite said first direction.

4. An apparatus for multi-spectral balanced imaging, the apparatus comprising:

(a) a first member operable to produce from incident light a first band having first band wavelengths and a second band;

(b) a second member positioned to receive said second band from said first member, said second member being operable to produce from said second band a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths;

(c) a first detector for producing a first image by detecting said first band; and

(d) a second detector for producing a second image by detecting said third band after said third band has propagated from said second member to said second detector,

wherein a first intensity associated with said first band is substantially equal to a second intensity associated with said third band when said incident light is uniform, wherein said first member reflects said first band from said first member and transmits said second band through said first member, wherein said second member reflects said third band from said second member toward said first member, wherein said first member receives said third band from said second member and transmits said third band through said first member, wherein said first intensity is associated with said first band when said first band is being detected by said first detector, and wherein said second intensity is associated with said third band when said third band is being detected by said second detector.

5. The apparatus of claim 4 wherein said second member comprises one or more components selected from the group of components consisting of a mirror, an edge filter, a shortpass filter, a longpass filter, a notch filter, a band reflection filter and a dichroic filter.

6. The apparatus of claim 5 wherein said second member comprises a mirror such that said second and third bands have substantially identical wavelengths.

7. The apparatus of claim 6 wherein the apparatus is operable to determine from said first and second images a flow rate associated with a gas plume.

8. The apparatus of claim 4 wherein the apparatus is operable to determine from said first and second images a flow rate associated with a gas plume.

9. The apparatus of claim 4 further comprising an entry mirror, the apparatus being operable to permit said notch filter and said second member to rotate in a first direction and said entry mirror to rotate in a second direction opposite said first direction.

10. A method of producing multi-spectral balanced images, the method comprising:

(a) producing from incident light by a notch filter a first band having first band wavelengths and a second band;

(b) receiving by a band reflection filter said second band from said notch filter and producing from said second band by said band reflection filter a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths, said band reflection filter having its center substantially coinciding with the center of said notch filter, said notch filter and said band reflection filter being selected such that a first intensity associated with said first band is substantially equal to a second intensity associated with said third band when said incident light is uniform;

(c) producing a first image by detecting said first band by a first detector; and

(d) producing a second image by detecting said third band by a second detector after said third band has propagated from said band reflection filter through said notch filter to said second detector.

11. The method of claim 10 further comprising determining from said first and second images a flow rate associated with a gas plume.

12. The method of claim 10 further comprising permitting said notch filter and said band reflection filter to rotate in unison while permitting an entry mirror associated with said incident light to rotate in an opposite direction.

13. A method of producing multi-spectral balanced images, the method comprising:

(a) receiving incident light by a first member, producing from said incident light by said first member a first band having first band wavelengths and a second band, reflecting said first band from said first member, and transmitting said second band through said first member;

(b) receiving by a second member said second band from said first member, producing from said second band by said second member a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths, such that a first intensity associated with said first band is substantially equal to a second intensity associated with said third band when said incident light is uniform;

(c) reflecting said third band from said second member toward said first member;

(d) receiving by said first member said third band from said second member, then transmitting said third band through said first member;

(e) producing a first image by detecting said first band by a first detector; and

(f) producing a second image by detecting said third band by a second detector after said third band has propagated from said second member to said second detector,

wherein producing a first image by detecting said first band by a first detector comprises detecting said first intensity, and wherein producing a second image by detecting said third band by a second detector after said third band has propagated from said second member to said second detector comprises detecting said second intensity.

14. The method of claim 13 wherein receiving by a second member said second band from said first member and producing from said second band by said second member a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths comprises producing said third band by one or more components selected from the group of components consisting of a mirror, an edge filter, a shortpass filter, a longpass filter, a notch filter, a band reflection filter and a dichroic filter.

15. The method of claim 14 wherein producing said third band by one or more components selected from the group of components consisting of a mirror, an edge filter, a shortpass filter, a longpass filter, a notch filter, a band reflection filter and a dichroic filter comprises producing said third band by a mirror such that said second and third bands have substantially identical wavelengths.

16. The method of claim 15 further comprising determining from said first and second images a flow rate associated with a gas plume.

17. The method of claim 13 further comprising determining from said first and second images a flow rate associated with a gas plume.

18. The method of claim 13 further comprising permitting said first member and said second member to rotate in unison while permitting an entry mirror associated with said incident light to rotate in an opposite direction.

19. An apparatus for multi-spectral balanced imaging, the apparatus comprising:

(a) first means for producing from incident light a first band having first band wavelengths and a second band, said first means reflecting said first band from said first member and transmits said second band through said first member;

(b) second means for receiving said second band from said first member and producing from said second band a third band having wavelengths shorter than said first band wavelengths, excluding said first band wavelengths and having wavelengths longer than said first band wavelengths, said second means reflecting said third band from said second means toward said first means, said first means receiving said third band from said second means and transmitting said third band through said first means;

(c) first detection means for producing a first image by detecting said first band, said first detection means detecting a first intensity associated with said first band; and

(d) second detection means for producing a second image by detecting said third band after said third band has propagated from said second means to said second detection means, said second detection means detecting a second intensity associated with said third band,

wherein said first intensity is substantially equal to said second intensity when said incident light is uniform.

20. The apparatus of claim 19 further comprising means for determining from said first and second images a flow rate associated with a gas plume.