CN116558642A - Dual-channel hyperspectral imaging device and method based on Sagnac interferometer - Google Patents
Dual-channel hyperspectral imaging device and method based on Sagnac interferometer Download PDFInfo
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- CN116558642A CN116558642A CN202310480450.4A CN202310480450A CN116558642A CN 116558642 A CN116558642 A CN 116558642A CN 202310480450 A CN202310480450 A CN 202310480450A CN 116558642 A CN116558642 A CN 116558642A
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- 238000000701 chemical imaging Methods 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000003384 imaging method Methods 0.000 claims abstract description 32
- 238000010008 shearing Methods 0.000 claims abstract description 29
- 230000003287 optical effect Effects 0.000 claims description 14
- 238000001228 spectrum Methods 0.000 claims description 14
- 230000005540 biological transmission Effects 0.000 claims description 9
- 229910021532 Calcite Inorganic materials 0.000 claims description 6
- 238000004026 adhesive bonding Methods 0.000 claims description 3
- 239000012788 optical film Substances 0.000 claims description 3
- 238000010408 sweeping Methods 0.000 claims description 3
- 230000009977 dual effect Effects 0.000 claims 1
- 230000003595 spectral effect Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/12—Generating the spectrum; Monochromators
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0202—Mechanical elements; Supports for optical elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N2021/0106—General arrangement of respective parts
- G01N2021/0112—Apparatus in one mechanical, optical or electronic block
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
Abstract
The invention discloses a dual-channel hyperspectral imaging device and method based on a Sagnac interferometer. Incident light from a target is collimated and emitted after passing through a front imaging objective, a diaphragm and a collimating objective, then enters and emits to a Wollaston prism after passing through a polarizer, the Wollaston prism shears the incident light into o light and e light in different directions, after passing through a Sagnac sub-band shearing structure, the o light and the e light in different wave bands generate different transverse shearing amounts, are emitted in different directions, pass through a polaroid array and a filter array, and finally are imaged on an area array detector through a rear imaging objective to form interference images in two different wave bands which are spatially separated. According to the invention, two sets of interferograms in different wave bands can be obtained through one push-broom, and high-resolution spectral imaging in a wide wave band range is realized.
Description
Technical Field
The invention belongs to the technical field of spectrum imaging, and particularly relates to a dual-channel hyperspectral imaging device and method based on a Sagnac interferometer.
Background
Spectral imaging technology is widely applied, and has important application in geological exploration, atmospheric remote sensing and military. With the development of imaging spectroscopic technology, broadband and high-resolution detection is widely emphasized. However, in the actual detection process, due to the limitation of the number of sampling points of the detector, the detected spectrum range is relatively narrow, the spectrum resolution and the spectrum range are mutually restricted, the high spectrum resolution can be realized only in a relatively narrow wave band, and the spectrum resolution is limited in a wide wave band range.
In the conventional spectral interference system, the optical path difference values of adjacent wavelengths are the same, and the wave number interval of two spectral lines differing by one fringe cannot be made smaller, so that the spectral resolution is limited in the range of the optical path difference limited by imaging. In order to improve the spectral resolution of an interference imaging spectrometer, a conventional method is to place a dispersion element in an optical path to introduce dispersion shearing, and squeeze optical path differences of different wavelengths to realize optical path difference modulation of light beams with different wavelengths so as to improve the spectral resolution of a system, but the method can only be realized in a narrow-band range and cannot realize high-spectral resolution imaging in a wide-band range.
Disclosure of Invention
The invention aims to provide a dual-channel hyperspectral imaging device and method based on a Sagnac interferometer, which are used for solving the problem that the spectral resolution is limited in a wide-band range in the traditional interference spectrum imaging technology.
The technical solution for realizing the purpose of the invention is as follows: in one aspect, a dual-channel hyperspectral imaging device based on a Sagnac interferometer is provided, and the device comprises a front imaging objective lens, a diaphragm, a collimating objective lens, a polarizer, a Wollaston prism, a Sagnac sub-band shearing structure, a polaroid array, an optical filter array, a rear imaging objective lens and an area array detector which are sequentially arranged along the light path direction;
the incident light from the target is imaged on the diaphragm through the front imaging objective lens, then a collimated light beam is formed through the collimating objective lens, the collimated light beam is incident to the Wollaston prism after passing through the polarizer, the Wollaston prism shears the incident light into o light and e light in different directions, after passing through the Sagnac sub-band shearing structure, the o light and the e light in different wave bands generate different transverse shearing amounts, the o light and the e light are emitted in different directions, sequentially pass through the polaroid array and the optical filter array, finally interference occurs on the area array detector after passing through the rear imaging objective lens, and interference images in two wave bands which are spatially separated are formed.
Further, the Wollaston prism is formed by gluing two calcite right-angle prisms with the same bottom surfaces, and optical axes of the two calcite right-angle prisms are orthogonal.
Further, the Sagnac shearing structure comprises a beam splitting prism, a reflecting mirror and a reflecting mirror flat plate, wherein an optical film is plated on the surface of the reflecting mirror flat plate, and the reflection and the transmission of light in different wave bands can be simultaneously realized.
Further, the front surface of the reflector plate reflects the wave band A, the transmission wave band B and the back surface reflects the wave band B, and the light of the two wave bands generates different transverse shearing amounts.
Further, the thickness of the mirror plate is adjustable to introduce different amounts of lateral shear for different bands of light.
Further, the polarizer array is a 2×1 array, and the light transmission axis direction is the same as the vibration direction of o light and e light, respectively.
Further, the filter array is a 2×1 array, and transmits the wave band a and the wave band B respectively.
In another aspect, a dual-channel hyperspectral imaging method based on a Sagnac interferometer is provided, comprising the steps of:
step 1, incident light is imaged at a diaphragm through a front imaging objective lens, then a collimated beam is formed through a collimating objective lens, and the incident light enters a Wollaston prism after passing through a polarizer;
step 2, the incident light is sheared into two beams of o light and e light by a Wollaston prism, and the two beams of emergent light are respectively deflected upwards and downwards;
step 3, two outgoing light beams are incident into the Sagnac sub-band shearing structure, light beams in different wave bands respectively generate different transverse shearing amounts through the front surface and the rear surface of the reflector plate M2, o light is deflected upwards to be outgoing, and e light is deflected downwards to be outgoing;
step 4, the polarizer array gates o light and e light respectively, and after passing through the filter array, the light of the wave band A in the o light is transmitted, and the light of the wave band B in the e light is transmitted;
and 5, after passing through the rear imaging objective lens, the light of the two wave bands is interfered on the area array detector to form an upper interference pattern and a lower interference pattern.
Further, the method further comprises:
step 6, pushing and sweeping an imaging target by a dual-channel hyperspectral imaging device based on a Sagnac interferometer, and changing the incidence angle of target light to modulate the light path difference to obtain interference image sequences under two groups of different wave bands;
and 7, performing spectrum restoration according to the acquired interference image information to obtain the spectrum information of each target point under the two wave bands.
Compared with the prior art, the invention has the remarkable advantages that:
1) And adopting Wollaston beam splitting and Sagnac shearing structures to realize the multi-band interference imaging from two dimensions.
2) The M2 reflecting mirror of the Sagnac shearing structure is coated, so that broadband detection can be realized under the condition of guaranteeing the spectral resolution.
The invention is described in further detail below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a dual-channel hyperspectral imaging device based on a Sagnac interferometer in one embodiment.
FIG. 2 is a schematic diagram of Wollaston prism splitting in one embodiment.
Fig. 3 is a schematic space structure of a Sagnac subband shearing mechanism according to an embodiment.
Fig. 4 is a schematic cross-sectional view of a mirror M2 in one embodiment.
FIG. 5 is a schematic diagram of a polarizer array in one embodiment.
FIG. 6 is a schematic diagram of an embodiment of a filter array.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present invention, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.
In one embodiment, in combination with fig. 1, there is provided a dual-channel hyperspectral imaging apparatus based on a Sagnac interferometer, the apparatus including a front imaging objective 1, a diaphragm 2, a collimator objective 3, a polarizer 4, a Wollaston prism 5, a Sagnac subband shearing structure 6, a polarizer array 7, an optical filter array 8, a rear imaging objective 9, and an area array detector 10, which are sequentially arranged along the direction of the optical path;
incident light from a target is imaged on a diaphragm 2 through a front imaging objective lens 1, then a collimated light beam is formed through a collimating objective lens 3, the collimated light beam is incident on a Wollaston prism 5 through a polarizer 4, the Wollaston prism 5 shears the incident light into o light and e light in different directions, after the incident light is subjected to a Sagnac sub-band shearing structure 6, the o light and the e light in different bands generate different transverse shearing amounts, the o light and the e light are emitted in different directions, sequentially pass through a polaroid array 7 and a filter array 8, finally interference occurs on an area array detector 10 after passing through a rear imaging objective lens 9, and interference images in two bands which are spatially separated are formed.
Further, in one embodiment, the Wollaston prism 5 is formed by gluing two rectangular calcite prisms with identical bottom surfaces, and optical axes of the two rectangular calcite prisms are orthogonal. Referring to fig. 2, the wollaston prism 5 shears incident light into o light and e light in different directions, and the deflection angles of the two light beams are respectively
Further, referring to fig. 3, the sagnac sub-band shearing structure 6 includes a beam splitter prism BS, a mirror M1, and a mirror plate M2, where M2 has a thickness d, the lateral shearing amount of the a band is s1, and the lateral shearing amount of the B band is s2. Referring to fig. 4, the surface of the mirror plate M2 is coated with an optical film, so that light with different wavebands can be reflected and transmitted simultaneously, wherein the front surface reflects the waveband a, the transmission waveband B, and the rear surface reflects the waveband B.
Further, in one embodiment, referring to fig. 5, the polarizer array 7 is a 2×1 array, and the directions of the transmission axes thereof are the directions of vibration of o light and e light, respectively, and the arrows in the figure represent the directions of the transmission axes thereof. Referring to fig. 6, the filter array 8 is a 2×1 array that is transparent to bands a and B, respectively.
In one embodiment, a dual-channel hyperspectral imaging method based on a Sagnac interferometer is provided, comprising the steps of:
step 1, incident light is imaged at a diaphragm through a front imaging objective lens, then a collimated beam is formed through a collimating objective lens, and the incident light enters a Wollaston prism after passing through a polarizer;
step 2, the incident light is sheared into two beams of o light and e light by a Wollaston prism, and the two beams of emergent light are respectively deflected upwards and downwards;
step 3, two outgoing light beams are incident into the Sagnac sub-band shearing structure, light beams in different wave bands respectively generate different transverse shearing amounts through the front surface and the rear surface of the reflector plate M2, o light is deflected upwards to be outgoing, and e light is deflected downwards to be outgoing;
step 4, the polarizer array gates o light and e light respectively, and after passing through the filter array, the light of the wave band A in the o light is transmitted, and the light of the wave band B in the e light is transmitted;
and 5, after passing through the rear imaging objective lens, the light of the two wave bands is interfered on the area array detector to form an upper interference pattern and a lower interference pattern.
Further, in one of the embodiments, the method further comprises:
step 6, pushing and sweeping an imaging target by a dual-channel hyperspectral imaging device based on a Sagnac interferometer, and changing the incidence angle of target light to modulate the light path difference to obtain interference image sequences under two groups of different wave bands;
and 7, performing spectrum restoration according to the acquired interference image information to obtain the spectrum information of each target point under the two wave bands.
In conclusion, the dual-channel hyperspectral imaging device based on the Sagnac interferometer is adopted, and the M2 reflecting mirror of the Wollaston prism beam splitting and Sagnac shearing structure is used for coating films, so that the imaging in a wide-band range is realized while the high spectral resolution is ensured. The spectrum information under different wave bands can be obtained by one push-broom, and the device has simple structure and good imaging quality.
The foregoing has outlined and described the basic principles, features, and advantages of the present invention. It will be understood by those skilled in the art that the foregoing embodiments are not intended to limit the invention, and the above embodiments and descriptions are meant to be illustrative only of the principles of the invention, and that various modifications, equivalent substitutions, improvements, etc. may be made within the spirit and scope of the invention without departing from the spirit and scope of the invention.
Claims (9)
1. The double-channel hyperspectral imaging device based on the Sagnac interferometer is characterized by comprising a front imaging objective, a diaphragm, a collimating objective, a polarizer, a Wollaston prism, a Sagnac sub-band shearing structure, a polaroid array, an optical filter array, a rear imaging objective and an area array detector which are sequentially arranged along the light path direction;
the incident light from the target is imaged on the diaphragm through the front imaging objective lens, then a collimated light beam is formed through the collimating objective lens, the collimated light beam is incident to the Wollaston prism after passing through the polarizer, the Wollaston prism shears the incident light into o light and e light in different directions, after passing through the Sagnac sub-band shearing structure, the o light and the e light in different wave bands generate different transverse shearing amounts, the o light and the e light are emitted in different directions, sequentially pass through the polaroid array and the optical filter array, finally interference occurs on the area array detector after passing through the rear imaging objective lens, and interference images in two wave bands which are spatially separated are formed.
2. The dual-channel hyperspectral imaging device based on a Sagnac interferometer as claimed in claim 1, wherein the Wollaston prism is formed by gluing two calcite right-angle prisms with the same bottom surface, and the optical axes of the two calcite right-angle prisms are orthogonal.
3. The dual-channel hyperspectral imaging device based on a Sagnac interferometer of claim 1, wherein the Sagnac shearing structure comprises a beam splitting prism, a reflecting mirror and a reflecting mirror plate, and the surface of the reflecting mirror plate is plated with an optical film, so that the reflection and the transmission of light in different wave bands can be realized simultaneously.
4. The dual-channel hyperspectral imaging apparatus and method based on a Sagnac interferometer as recited in claim 3, wherein the front surface reflection band a, transmission band B, and back surface reflection band B of the mirror plate produce different amounts of lateral shearing of the light in the two bands.
5. The dual channel hyperspectral imaging apparatus and method based on a Sagnac interferometer as recited in claim 4, wherein the thickness of the mirror plate is adjustable to introduce different amounts of lateral shear for different bands of light.
6. The dual-channel hyperspectral imaging apparatus and method based on a Sagnac interferometer as claimed in claim 5, wherein the polarizer array is a 2 x 1 array, and the direction of the transmission axis is the same as the vibration direction of o light and e light, respectively.
7. The dual-channel hyperspectral imaging apparatus and method based on a Sagnac interferometer as claimed in claim 6, wherein the filter array is a 2×1 array, and the filter array transmits the wave band a and the wave band B respectively.
8. A dual-channel hyperspectral imaging method based on a Sagnac interferometer based on the device of any one of claims 1 to 7, characterized in that it comprises the following steps:
step 1, incident light is imaged at a diaphragm through a front imaging objective lens, then a collimated beam is formed through a collimating objective lens, and the incident light enters a Wollaston prism after passing through a polarizer;
step 2, the incident light is sheared into two beams of o light and e light by a Wollaston prism, and the two beams of emergent light are respectively deflected upwards and downwards;
step 3, two outgoing light beams are incident into the Sagnac sub-band shearing structure, light beams in different wave bands respectively generate different transverse shearing amounts through the front surface and the rear surface of the reflector plate M2, o light is deflected upwards to be outgoing, and e light is deflected downwards to be outgoing;
step 4, the polarizer array gates o light and e light respectively, and after passing through the filter array, the light of the wave band A in the o light is transmitted, and the light of the wave band B in the e light is transmitted;
and 5, after passing through the rear imaging objective lens, the light of the two wave bands is interfered on the area array detector to form an upper interference pattern and a lower interference pattern.
9. The dual-channel hyperspectral imaging method based on a Sagnac interferometer of claim 8, further comprising:
step 6, pushing and sweeping an imaging target by a dual-channel hyperspectral imaging device based on a Sagnac interferometer, and changing the incidence angle of target light to modulate the light path difference to obtain interference image sequences under two groups of different wave bands;
and 7, performing spectrum restoration according to the acquired interference image information to obtain the spectrum information of each target point under the two wave bands.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310480450.4A CN116558642A (en) | 2023-04-28 | 2023-04-28 | Dual-channel hyperspectral imaging device and method based on Sagnac interferometer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310480450.4A CN116558642A (en) | 2023-04-28 | 2023-04-28 | Dual-channel hyperspectral imaging device and method based on Sagnac interferometer |
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| CN116558642A true CN116558642A (en) | 2023-08-08 |
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| CN202310480450.4A Pending CN116558642A (en) | 2023-04-28 | 2023-04-28 | Dual-channel hyperspectral imaging device and method based on Sagnac interferometer |
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