CN115993186A - Hand-held multispectral imager - Google Patents
Hand-held multispectral imager Download PDFInfo
- Publication number
- CN115993186A CN115993186A CN202111208227.1A CN202111208227A CN115993186A CN 115993186 A CN115993186 A CN 115993186A CN 202111208227 A CN202111208227 A CN 202111208227A CN 115993186 A CN115993186 A CN 115993186A
- Authority
- CN
- China
- Prior art keywords
- filter film
- cut
- film
- band
- filter
- Prior art date
- Legal status (The legal status 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 status listed.)
- Pending
Links
Images
Landscapes
- Solid State Image Pick-Up Elements (AREA)
Abstract
The invention provides a handheld multispectral imager which comprises an image sensor, wherein the image sensor comprises a pixel photosensitive unit, a light splitting structure, a transition layer, a first stop filter film, a second stop filter film and a third stop filter film, the narrow-band filter film in the light splitting structure integrally deposits and grows on the pixel photosensitive unit, the transition layer integrally deposits and grows on the narrow-band filter film, a first stop filter film integrally deposits and grows on the narrow-band filter film, the transition layer is used for transiting two film systems of the narrow-band filter film and the first stop filter film, a second stop filter film is arranged on the first stop filter film, the third stop filter film is arranged on the second stop filter film, and the first stop filter film, the second stop filter film and the third stop filter film are respectively used for stopping a first interference wave band, a second interference wave band and a third interference wave band. By applying the technical scheme of the invention, the technical problems of low spectral transmittance and low quantum efficiency caused by a cut-off filter film attaching mode in the prior art are solved.
Description
Technical Field
The invention relates to the technical field of spectrum imaging, in particular to a handheld multispectral imager.
Background
The hyperspectral imaging system (Hyper Spectral Imaging, HSI for short) can obtain a three-dimensional spectrum image with a characteristic of 'map unification' formed by two-dimensional space image information and one-dimensional spectrum information, and can observe the space information of two-dimensional distribution and the spectrum information on each pixel point.
The image space information reflects external characteristics such as the size, shape, defects and the like of the target object, and the spectrum information can reflect physical and chemical components of the target object. Therefore, physical and chemical information such as material, components and the like can be identified by analyzing and processing the spectrum information, and related positions and ranges can be identified rapidly and intuitively by the space information of the image.
In a classical HSI system, because the system is based on a single discrete device, in order to ensure spatial resolution and spectral resolution, optical devices such as an objective lens, a diaphragm, a collimator, various lenses and the like must be introduced, and focusing and collimation problems among various devices must be considered, so that the complexity, the volume and the cost of the traditional HSI system are high, and the application range is greatly limited.
Furthermore, in order to complete the filtering out of the target feature spectrum segment and realize the target distinction, the narrow-band filter film is integrated on the image sensor, so that the tunable filtering at the center of the required wave band can be realized (as shown in fig. 6, the center wavelength of the narrow-band filter film is tunable within a certain range). However, due to the limitation of the refractive index of the existing high-low materials, the spectral bandwidth range cannot cover the full spectrum (as shown in fig. 6, the cut-off bandwidth is less than 200 nm), and the interference of signals with other wave bands exists as shown in fig. 7, and the interference has other wave band influences besides the required wave band. An external cut-off filter film (as shown in fig. 8) is required to cut off the interference band. The existing external cut-off filter film is coated separately and then attached to the image sensor, so that the spectral transmittance is reduced, the quantum efficiency is reduced, and the imaging effect is affected.
Existing hand-held portable spectral imaging devices typically employ a conventional mechanism, i.e., a separate light splitting and imaging assembly, including the following three common approaches. In the first aspect, a switched filter is disposed in front of an image sensor. The scheme can only image one spectrum at the same time, and when the spectrum needs to be switched to the other spectrum, the required new optical filter is moved/rotated to the front of the imaging component through a mechanical structure. The design mode introduces a large number of movable mechanisms, seriously influences the integration level and stability of the system, reduces the fault-free operation time of the system and improves the maintenance difficulty. Meanwhile, the existence of the movable mechanism and the filter array tends to cause the increase of the total volume of the system; and a plurality of spectral images of the same picture are acquired, fixation and multi-time switching filter imaging are required to be kept, and the aim of quickly acquiring a complete spectrum data cube cannot be achieved. In a second scheme, a Liquid Crystal Tunable Filter (LCTF) unit is disposed in front of the image sensor. The voltage control LCTF is adjusted to be transparent to a certain wavelength, then the image sensor performs imaging, and then the voltage control LCTF is adjusted to the next wavelength, and the operation is repeated. The process is similar to scheme one. In addition to the disadvantages of low imaging rate and need to maintain gaze, this method has the problems of low light transmittance and uneven transmittance in the field of view. Under normal light sources, it is basically difficult to clearly image the target. And in the third scheme, a MEMS-FP cavity (micro-electromechanical system-Fabry-Perot resonant cavity) filtering unit is arranged in front of the image sensor. The scheme is similar to the scheme II, and the thickness of the FP cavity is controlled through the MEMS mechanism, so that the filtering effect of different spectral bands is realized. Besides the defects, the conventional MEMS-FP cavity filter has the defects that the field of view is difficult to achieve more than the mm level, the transmittance is low, and the MEMS-FP cavity filter is only suitable for single-point detection and is difficult to use for imaging detection.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art.
The invention provides a handheld multispectral imager, which comprises an image sensor, wherein the image sensor comprises: the pixel photosensitive unit is used for realizing image acquisition and data reading; the light splitting structure comprises a plurality of periods which are distributed periodically, each period comprises a narrow-band filter film, the narrow-band filter films are integrally deposited and grown on the pixel photosensitive units, and the narrow-band filter films are used for realizing the tunability of the central wavelength of a required wave band; the narrow-band filter film comprises a plurality of FP cavity structures which are distributed in a mosaic manner; the transition layer is integrally deposited and grown on the light splitting structure; the first cut-off filter film is integrally deposited and grown on the transition layer and is used for cutting off a first interference wave band; the transition layer is used for transiting two film systems of the narrow-band filter film and the first cut-off filter film; the second cut-off filter film is arranged on the first cut-off filter film and is used for cutting off a second interference wave band, and the second interference wave band is different from the first interference wave band; the third cut-off filter film is arranged on the second cut-off filter film and used for cutting off a third interference wave band, and the third interference wave band is different from the first interference wave band and the second interference wave band.
Further, the film structure of the image sensor is sub|H (LH) ≡S 1 2nL(HL)^S 1 H Ln 1 (W1)^S 2 n 2 (W2)^S 3 n 3 (W3)^S 4 |Air，H(LH)^S 1 2nL(HL)^S 1 H is a film system structure of a narrow-band filter film, L is a film system structure of a transition layer, W1, W2 and W3 all comprise a high-refractive-index material and a low-refractive-index material, and n 1 (W1)^S 2 A film system structure of a first cut-off filter film, n 2 (W2)^S 3 A film system structure of a second cut-off filter film, n 3 (W3)^S 4 Is a film system structure of a third cut-off filter film, H is a high refractive index material, L is a low refractive index material, S 1 、S 2 、S 3 And S is 4 For the number of overlapping times, n is the film thickness adjustment coefficient of the narrow-band filter film, n 1 For the film thickness adjustment coefficient of the first cut-off filter film,n 2 for adjusting the coefficient of the film thickness of the second cut-off filter film, n 3 And (3) adjusting the coefficient for the thickness of the film layer of the third stop filter film.
Further, in the film system structure of the first cut filter film, W1 includes (0.5LH0.5L) or (0.5HL0.5H); in the second cut filter film, W2 includes (0.5LH0.5L) or (0.5HL0.5H); in the third cut filter film, W3 includes (0.5LH0.5L) or (0.5HL0.5H).
Further, the first cut-off filter film, the second cut-off filter film and the third cut-off filter film are prepared by alternately depositing a high refractive index material and a low refractive index material, and the high refractive index materials of the first cut-off filter film, the second cut-off filter film and the third cut-off filter film comprise Ta 2 O 5 、Ti 3 O 5 、TiO 2 、Si 3 N 4 Or Nb (Nb) 2 O 5 The low refractive index materials of the first, second and third stop filter films each include SiO 2 、MgF 2 And Al 2 O 3 At least one of them.
Further, the second cut-off filter film is adhesively disposed on the first cut-off filter film.
Further, a second cut-off filter film is integrally deposited and grown on the first cut-off filter film.
Further, a third cut-off filter film is adhesively provided on the second cut-off filter film.
Further, a third stop filter film is integrally deposited and grown on the second stop filter film.
Further, each period also comprises a plurality of polarization filtering structures with different polarization directions, and the plurality of polarization filtering structures and the plurality of FP cavity structures are arranged randomly.
Further, each period includes four polarization filter structures, and the polarization angles of the four polarization filter structures are 0 °, 45 °, 90 °, and 135 °, respectively.
Further, each period further includes at least one full-spectral-band structure, the at least one full-spectral-band structure being randomly arranged with the plurality of polarization filtering structures and the plurality of FP cavity structures.
Further, each period further includes at least one bandpass wide spectrum filter structure, the at least one bandpass wide spectrum filter structure being randomly arranged with the plurality of polarization filter structures and the plurality of FP cavity structures.
Further, the handheld multispectral imager further includes: the imaging lens group is used for transmitting light in the spectrum range index of the handheld multispectral imager and converging the transmitted light on the image sensor; a readout circuit connected to the image sensor; the control circuit comprises a processor and a communication module, and the processor is respectively connected with the reading circuit and the communication module.
By applying the technical scheme of the invention, the handheld multispectral imager comprises an image sensor, wherein the image sensor integrally deposits and grows a narrow-band filter film on a pixel photosensitive unit, a transition layer integrally deposits and grows a narrow-band filter film on the transition layer, a first cut-off filter film integrally deposits and grows on the transition layer, no gap exists among the first cut-off filter film, the transition layer, the narrow-band filter film and the pixel photosensitive unit, the spectral transmittance is high, the energy loss is reduced, the one-time preparation process is integrally formed, the environment pollution is avoided, the firmness is better, and the preparation efficiency and the integration level are higher; by disposing the second cut-off filter film on the first cut-off filter film and disposing the third cut-off filter film on the second cut-off filter film, the cut-off range of the interference band can be effectively widened. In addition, because the equivalent refractive indexes of the narrow-band filter film and the first cut-off filter film are different, the peak transmittance can be influenced by direct superposition, and the peak transmittance of the image sensor can be effectively improved by arranging the transition layer between the narrow-band filter film and the first cut-off filter film. Compared with the external attaching cut-off filter film in the prior art, the image sensor in the handheld multispectral imager provided by the invention integrates the first cut-off filter film and the narrow-band filter film in the image sensor, so that the quantum efficiency and the spectral transmittance are greatly improved; the second cut-off filter film is arranged on the first cut-off filter film, and the third cut-off filter film is arranged on the second cut-off filter film, so that the cut-off range of an interference wave band can be widened; and a transition layer is arranged between the narrow-band filter film and the first cut-off filter film, so that the peak transmittance of the image sensor is effectively improved, and the spectrum resolution capability of the handheld multispectral imager can be effectively improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
Fig. 1 is a schematic view showing a partial structure of an image sensor (a narrow-band filter film only shows one FP cavity structure) provided according to an embodiment of the present invention;
fig. 2 is a schematic diagram showing a spectroscopic structure of an image sensor according to an embodiment of the present invention;
fig. 3 is a schematic view showing a single periodic structure of a spectroscopic structure having a polarization filtering structure according to an embodiment of the present invention;
FIG. 4 shows a schematic diagram of a handheld multispectral imager provided in accordance with a specific embodiment of the invention;
FIG. 5 shows a schematic diagram of a prior art polarized image sensor;
FIG. 6 shows a schematic filtering diagram of a prior art narrow band filter;
FIG. 7 shows a schematic diagram of filtering a narrow band filter film in the prior art in the presence of other band signal interference;
fig. 8 shows a schematic filtering diagram of a prior art cut-off filter film.
Wherein the above figures include the following reference numerals:
10. a pixel light sensing unit; 20. a narrow band filter film; 30. a first cut-off filter film; 40. a transition layer; 60. a second cut-off filter film; 70. and a third stop filter film.
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
As shown in fig. 1, as a first specific embodiment of the present invention, there is provided a hand-held multispectral imager including an image sensor including: the pixel light sensing unit 10, the light splitting structure, the transition layer 40, the first cut-off filter film 30, the second cut-off filter film 60 and the third cut-off filter film 70, wherein the pixel light sensing unit 10 is used for realizing image acquisition and data readout; the light splitting structure comprises a plurality of periods which are distributed periodically, each period comprises a narrow-band filter film 20, the narrow-band filter films 20 are integrally deposited and grown on the pixel photosensitive units 10, and the narrow-band filter films 20 are used for realizing the tunability of the central wavelength of a required wave band; the narrow-band filter film 20 comprises a plurality of FP cavity structures distributed in a mosaic manner; the transition layer 40 is integrally deposited and grown on the light splitting structure; the first cut-off filter film 30 is integrally deposited and grown on the transition layer 40, and the first cut-off filter film 30 is used for cutting off a first interference wave band; the transition layer 40 is used for transiting two film systems of the narrow-band filter film 20 and the first cut-off filter film 30; the second cut-off filter film 60 is disposed on the first cut-off filter film 30, and the second cut-off filter film 60 is used for cutting off a second interference wave band, and the second interference wave band is different from the first interference wave band; the third cut-off filter film 70 is disposed on the second cut-off filter film 60, and the third cut-off filter film 70 is used for cutting off a third interference band, which is different from the first interference band and the second interference band.
In the first embodiment of the invention, the handheld multispectral imager comprises an image sensor, wherein the image sensor integrally deposits and grows a narrow-band filter film on a pixel photosensitive unit, a transition layer integrally deposits and grows a narrow-band filter film, a first cut-off filter film integrally deposits and grows on the transition layer, no gap exists among the first cut-off filter film, the transition layer, the narrow-band filter film and the pixel photosensitive unit, the spectral transmittance is high, the energy loss is reduced, the one-time preparation process is integrally formed, the environment pollution is avoided, the firmness is better, and the preparation efficiency and the integration level are higher; by disposing the second cut-off filter film on the first cut-off filter film and disposing the third cut-off filter film on the second cut-off filter film, the cut-off range of the interference band can be effectively widened. In addition, because the equivalent refractive indexes of the narrow-band filter film and the first cut-off filter film are different, the peak transmittance can be influenced by direct superposition, and the peak transmittance of the image sensor can be effectively improved by arranging the transition layer between the narrow-band filter film and the first cut-off filter film. Compared with the external attaching cut-off filter film in the prior art, the image sensor in the handheld multispectral imager provided by the invention integrates the first cut-off filter film and the narrow-band filter film in the image sensor, so that the quantum efficiency and the spectral transmittance are greatly improved; the second cut-off filter film is arranged on the first cut-off filter film, and the third cut-off filter film is arranged on the second cut-off filter film, so that the cut-off range of an interference wave band can be widened; the transition layer is arranged between the narrow-band filter film and the first cut-off filter film, so that the peak transmittance of the image sensor is effectively improved, clear imaging can be realized under common outdoor illumination and common indoor illumination, the image contrast is high, dependence on an external light source and internal subsequent gain is small, the reduction of information in each spectral range is relatively perfect, and the spectral resolution of the handheld multispectral imager can be effectively improved.
As shown in fig. 2, a specific embodiment is provided, the size of the light splitting structure is 4*4 as a period, each period includes 16 FP cavity structures of different spectrum segments distributed in a mosaic manner, and the spectral image of the spectrum segment corresponding to the position can be obtained by extracting and combining the pixel data of the same position in each period.
As a second embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the film system structure of the image sensor based on the first embodiment, in which the film system structure of the image sensor is configured as sub|h (LH) ≡s 1 2nL(HL)^S 1 H L n 1 (W1)^S 2 n 2 (W2)^S 3 n 3 (W3)^S 4 |Air，H(LH)^S 1 2nL(HL)^S 1 H is the film structure of the narrow band filter 20, L is the film structure of the transition layer 40, and W1, W2 and W3 each comprise a high refractive index material and a low refractive index materialRefractive index material, n 1 (W1)^S 2 Is a film system structure of the first cut-off filter film 30, n 2 (W2)^S 3 Is the film structure of the second cut-off filter film 60, n 3 (W3)^S 4 Is a film structure of the third stop filter film 70, H is a high refractive index material, L is a low refractive index material, S 1 、S 2 、S 3 And S is 4 For the number of overlapping times, n is the film thickness adjustment coefficient of the narrow-band filter film, n 1 For the film thickness adjustment coefficient, n, of the first cut-off filter film 30 2 For the film thickness adjustment coefficient, n, of the second cut-off filter film 60 3 The film thickness adjustment coefficient for the third stop filter film 70. In the second embodiment of the present invention, by configuring a specific model structure of the image sensor, it is possible to realize tunability of the center filtering in a desired band and prevent the interference of stray light. In the present invention, the film thickness adjustment coefficient n of the cut-off filter film 1 、n 2 And n 3 There are two determination methods, the first is obtained by software simulation, in which various filter curves can be simulated by software, and the most preferred film thickness adjustment coefficients are determined by the performance differences of tuned filter curves obtained by different parameters. The second way is by determining the band to be cut off of the cut-off filter; calculating and obtaining the central wavelength of the spectrum segment to be cut according to the first boundary threshold value and the second boundary threshold value of the spectrum segment to be cut; the film thickness adjusting coefficient of the cut-off filter film is determined according to the center wavelength of the spectrum to be cut-off and the center wavelength of the narrow-band filter film, and the film thickness adjusting coefficient is obtained in a numerical calculation mode, so that the calculation mode is simple, and the effective cut-off of a specific wave band can be realized. In the actual application process, the selection can be performed according to actual needs.
As a third embodiment of the present invention, there is provided a hand-held multispectral imager having a spectral imaging chip structure identical to that of the second embodiment. In the spectral imaging chip structure, S 1 ＝5-7，S 2 ，S 3 ，S 4 ＝8-13，n 1 ，n 2 ，n 3 ＝0.5-2.5。Wherein Sub is a substrate Si, air is Air, H represents a high refractive index material Ta 2 O 5 、Ti 3 O 5 、TiO 2 、Si 3 N 4 、Nb 2 O 5 One of them; l represents a low refractive index material SiO 2 、MgF 2 Al and 2 O 3 one or a mixture thereof.
As a fourth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the cutoff filter film on the basis of the above-described embodiments. In the embodiment, the first cut-off filter film is integrally deposited and grown on the narrow-band filter film by adopting a semiconductor process, and the first cut-off filter film is made of a material compatible with the semiconductor process, so that the spectral transmittance is further improved, and the energy loss is reduced. In the film system structure of the first cut filter film 30, W1 includes (0.5LH0.5L) or (0.5HL0.5H); the second cut filter film is disposed on the first cut filter film 30, and W2 includes (0.5LH0.5L) or (0.5HL0.5H) in the film system structure of the second cut filter film 60; the third cutoff filter film 70 is provided on the second cutoff filter film 60, and in the third cutoff filter film 70, W3 includes (0.5LH0.5L) or (0.5HL0.5H).
As a fifth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the cutoff filter film on the basis of the above-described embodiments. In this embodiment, the first, second and third cutoff filter films 30, 60 and 70 are each prepared by alternately depositing a high refractive index material and a low refractive index material. The high refractive index materials of the first, second and third cutoff filter films 30, 60 and 70 each include Ta 2 O 5 、Ti 3 O 5 、TiO 2 、Si 3 N 4 Or Nb (Nb) 2 O 5 The low refractive index materials of the first, second and third cutoff filter films 30, 60 and 70 each include SiO 2 、MgF 2 And Al 2 O 3 At least one of them.
As a sixth embodiment of the present invention, there is provided a handheld multispectral imager in which the manner of disposing the second cutoff filter film 60 is further defined on the basis of the above-described embodiments. In this embodiment, the second cut filter film 60 is adhesively disposed on the first cut filter film 30. In the sixth embodiment of the present invention, the image sensor can effectively cut off the interference band while simplifying the process by attaching the second cut-off filter film to the first cut-off filter film. Compared with the external attaching cut-off filter film in the prior art, the image sensor provided by the invention has the advantages that the first cut-off filter film and the narrow-band filter film are integrated in the image sensor, so that the quantum efficiency and the spectral transmittance are greatly improved; the second cut-off filter film is attached to the first cut-off filter film, so that the processing technology can be effectively simplified, the cut-off range of an interference wave band is widened, and the spectrum resolution capability of the handheld multispectral imager can be effectively improved.
As a seventh embodiment of the present invention, there is provided a handheld multispectral imager in which the manner of disposing the second cutoff filter film 60 is further defined on the basis of the above-described embodiments. In this embodiment, the second cut filter film 60 is integrally deposited and grown on the first cut filter film 30. The second cut-off filter film 60 can be integrated in the image sensor by disposing the second cut-off filter film 60 on the first cut-off filter film 30 by integral deposition growth, which has high spectral transmittance, greatly improving quantum efficiency and spectral transmittance.
As an eighth embodiment of the present invention, there is provided a handheld multispectral imager in which the manner of disposing the third stop filter film 70 is further limited on the basis of the above-described embodiments. In this embodiment, the third cut filter film 70 is adhesively provided on the second cut filter film 60. In the eighth embodiment of the present invention, the image sensor can effectively widen the cut-off range of the interference band while simplifying the processing process by attaching the third cut-off filter film to the second cut-off filter film. Compared with the external attaching cut-off filter film in the prior art, the image sensor provided by the invention has the advantages that the third cut-off filter film is attached to the second cut-off filter film, the processing technology can be effectively simplified, the cut-off range of an interference wave band is widened, and the spectrum resolution capability of the handheld multispectral imager can be effectively improved.
As a ninth embodiment of the present invention, there is provided a handheld multispectral imager in which the manner in which the third stop filter film 70 is disposed is further defined on the basis of the seventh embodiment. In this embodiment, the third cut filter film 70 is integrally deposited and grown on the second cut filter film 60. The third stop filter film 70 can be integrated in the image sensor by disposing the third stop filter film 70 on the second stop filter film 60 by integral deposition growth, which has high spectral transmittance, greatly improving quantum efficiency and spectral transmittance.
As a tenth embodiment of the present invention, there is provided a hand-held multispectral imager in which the structure of the narrow-band filter film is further defined on the basis of the above-described embodiments. Through setting up the structure of narrow band filter film, can effectively reduce the structural complexity of chip structure, reduce structure volume and reduce cost. In this embodiment, the pixel light sensing unit includes a plurality of pixel light sensing portions, a plurality of FP cavity structures are disposed in one-to-one correspondence with the plurality of pixel light sensing portions, the plurality of FP cavity structures are all formed in one step by using a semiconductor process, and any FP cavity structure includes a first mirror, a light-transmitting layer, and a second mirror that are sequentially stacked from bottom to top. The first reflecting mirror, the light passing layer, the second reflecting mirror and the pixel photosensitive part are made of materials compatible with semiconductor technology, and are strictly aligned in the longitudinal direction, and no later-attached part exists. In the mode, the traditional light splitting system is directly processed on the pixel photosensitive unit of the photoelectric sensor by means of advanced semiconductor (CMOS) process technology, stray light is reduced due to tight connection, photon utilization rate is improved, and therefore speed can reach hundred frames per second, and a spectrum video function is realized; the volume and the weight are not different from those of a common RGB chip, and an imaging system with the size of a finger is realized; CMOS technology gives an unparalleled degree of integration to image sensors, and can be connected with any circuit with high integration, such as embedded in a cell phone.
As an eleventh embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the first mirror and the second mirror on the basis of the tenth embodiment. In this embodiment, the first mirror is a lower mirror, the second mirror is an upper mirror, and the upper mirror is made of multiple layers of high-reflectivity materials and multiple layers of low-reflectivity materials alternately to form a bragg mirror, which are overlapped with each other for multiple times, and the reflectivity reaches over 99% as a cavity mirror of an FP cavity structure. The lower reflector has the same structure and material as the upper reflector, and is positioned between the light transmitting layer and the pixel photosensitive part, and has high reflection effect.
As a twelfth embodiment of the present invention, there is provided a handheld multispectral imager in which the film thickness adjustment coefficient of any one of the cutoff filter films is further defined on the basis of the above-described embodiments. In this embodiment, the film thickness adjustment coefficient may be obtained according to the following steps: determining a spectrum section to be cut off of any cut-off filter film; calculating and obtaining the central wavelength of the spectrum segment to be cut according to the first boundary threshold value and the second boundary threshold value of the spectrum segment to be cut; and determining the film thickness adjustment coefficient of any cut-off filter film according to the center wavelength of the to-be-cut-off spectrum and the center wavelength of the narrow-band filter film.
In the thirteenth embodiment of the invention, by optimally designing any cut-off filter film, namely by designing the film thickness adjustment coefficient of any cut-off filter film, specifically, calculating and obtaining the center wavelength of the to-be-cut-off spectrum according to the first boundary threshold value and the second boundary threshold value of the to-be-cut-off spectrum, determining the film thickness adjustment coefficient of the cut-off filter film through the center wavelength of the to-be-cut-off spectrum and the center wavelength of the narrow-band filter film, thus, when the cut-off filter film with the film thickness adjustment coefficient is integrally deposited on the narrow-band filter film, light leakage outside the free spectrum range can be greatly inhibited, cut-off of an interference wave band is completed, the side mode inhibition ratio of spectrum filtering is greatly improved, and the spectrum imaging performance of the image sensor is improved.
As a fourteenth embodiment of the present invention, there is provided a hand-held multispectral imager which defines a center wavelength of a spectrum to be cut off on the basis of the above-described embodiments. In this embodiment, the center wavelength of the spectral band to be cut-off may be based on
To obtain; alternatively, the center wavelength of the spectral band to be cut-off may be based on
Is obtained by, wherein lambda 0 Lambda is the center wavelength of the spectrum to be cut off 1 For a first boundary threshold, lambda, of the spectral band to be cut-off 2 Is a second boundary threshold for the portion of spectrum to be cut off. The above two methods for obtaining the center wavelength of the spectrum to be cut off are adopted
The center wavelength of the spectrum to be cut off is obtained, the calculation accuracy is higher, and the suppression of light leakage outside the free spectrum range (compared with the formula +.>
The center wavelength of the band to be cut off is obtained).
As a fifteenth embodiment of the present invention, there is provided a handheld multispectral imager in which the film thickness adjustment coefficient of any one of the cut-off filter films is defined on the basis of the above-described embodiments. In this embodiment, the film thickness adjustment coefficient n of any one of the cut-off filter films can be determined according to
Is obtained, wherein lambda is the center wavelength of the narrow-band filter film, n=n 1 、n 2 Or n 3 . In this way, the thickness of the film layer of the cut-off filter film is determinedThe adjustment coefficient can greatly inhibit light leakage outside the free spectrum range, cut-off of interference wave bands is completed, the side mode inhibition ratio of spectrum filtering is greatly improved, and the spectrum imaging performance of the image sensor is improved.
In the practical application process, especially for complex environments such as outdoor day and night alternation, haze weather and the like, the accuracy of information acquired by a microminiature spectrum imaging system based on a single chip is reduced, and accurate identification and judgment of a target are difficult. Polarized light has a relatively long history in machine vision inspection, such as detecting stress points, objects, reducing glare from transparent objects, and the like. Typical polarizing systems require one or more additional polarizers placed between the target and the camera to detect material stress, enhance contrast, and analyze surface indentations or scratches. The polarization imaging technology is a detection technology widely applied to outdoor target detection and industrial quality monitoring, and identifies targets according to the polarization characteristic difference of different targets. However, due to the limited types of targets with identifiable polarization characteristics, it is difficult to accurately judge multiple targets in a complex environment background by means of single polarization information. The spectrum imaging detection technology and the polarization detection technology are combined, and the spectrum information, the space information and the polarization information of the targets are collected at the same time, so that real-time effective monitoring and identification of complex background environments and multiple types of targets can be realized. In order to realize simultaneous acquisition of polarization information, spectrum information and imaging information, the prior art adopts a pixel-level integrated photonic crystal spectrum modulation structure and a 0 degree, 45 degree, 90 degree and 135 degree four-angle polarized photonic lattice structure overlapped along a light splitting layer of a vertical detector, as shown in fig. 5. The method can acquire target polarization and spectrum imaging information simultaneously, and can enhance contrast by utilizing polarization while utilizing spectrum to identify substances, so that the influence of complex background environment on identification results can be overcome to a certain extent. According to the technical scheme, the integrated photonic crystal structure achieves the effects of polarization and spectral filtering by changing the lattice constant and the lattice direction, and is complex in structure and high in process requirement. The single pixel contains spectrum information and polarization information, and the algorithm analysis difficulty is increased.
As a sixteenth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the spectroscopic structure on the basis of the first embodiment, in which each period of the spectroscopic structure further includes a plurality of polarization filter structures having different polarization directions, the plurality of polarization filter structures being arranged at random with the plurality of FP cavity structures.
In a sixteenth embodiment of the present invention, the handheld multispectral imager provided in the present embodiment has all the beneficial effects as the handheld multispectral imager in the first embodiment, and simultaneously, by preparing the FP cavity structure of the narrow-band filter film and the polarization filter structure in the same layer of the spectroscopic structure, the advantages of polarization enhancement and spectrum recognition can be combined, the accuracy of target recognition in a complex background environment can be improved, the dependence on external light sources and internal subsequent gains can be reduced, the restoration of information in each spectral range can be relatively perfect, and the spectrum resolution capability of the handheld multispectral imager can be effectively improved. Meanwhile, the structure is simple, the preparation process is mature, the spectrum information and polarization information analysis algorithm is simple, the method can be applied to scenes with severe and severe ambient light, such as at night, in dazzling or in haze, and the method can be widely used in the fields of security monitoring, military anti-camouflage application, outdoor environment monitoring, intelligent agriculture and the like.
As a seventeenth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined on the basis of the sixteenth embodiment, in which each period includes four polarization filter structures having polarization angles of 0 °, 45 °, 90 ° and 135 °, respectively.
In a seventeenth embodiment of the present invention, the polarization filtering structure adopts a four-quadrant wire grid structure with polarization angles of 0 °, 45 °, 90 ° and 135 °, respectively. The complete polarization information of the target can be formed by adopting the combination of the polarization information in the four directions. The four-quadrant wire grid has a simple structure, can be prepared by adopting a film, has a mature preparation process, and can comprehensively collect target polarization information. Further, on the basis of the sixteenth embodiment of the present invention, derivative changes may be performed based on four-quadrant polarization, so as to obtain other types of polarization filtering structures.
As an eighteenth embodiment of the present invention, as shown in fig. 3, there is provided a handheld multispectral imager, which is based on the sixteenth embodiment, and in which a plurality of polarization filter structures are further defined, the light splitting structures are alternately arranged with a size of 3*3 as a period, FP cavity structures of 5 spectral segments and polarization filter structures of 4 different polarization directions in each period, and the 5 FP cavity structures are of 5 different spectral segments, so as to form a four-adjacent-domain pixel spectrum and polarization information. The polarization filter structure and the FP cavity structure are alternately arranged, the obtained target spectrum and polarization information are uniform, the recovery of a real image is facilitated, and the analysis and calculation are facilitated. According to the four-adjacent-domain pixel spectrum and the polarization information, the periodic polarization and the spectrum information can be reconstructed to obtain the polarization and the spectrum information of the full picture of the space captured by the detector. According to the single period spectrum information, the spectrum curve of the object imaged in the period can be obtained, according to the four-quadrant wire grid structure, the polarization information of the incident light in the period can be obtained, according to the Stokes formula, the light polarization direction of the object in the period can be calculated, and the full-frame polarized image can be obtained.
The light splitting structure comprising the polarization filtering structure is applied to the image sensor, and the polarization and the spectral information of the spectrum can be interpolated and solved through the spectral information and the polarization information of adjacent pixels. The two-dimensional image spectrum information is obtained, meanwhile, the polarization information can be obtained, and the target classification and identification are carried out through the spectrum and polarization fusion information, so that the target identification accuracy under the special environment background is greatly improved.
As a nineteenth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined by the sixteenth embodiment, wherein each period of the light splitting structure further includes at least one fully-transmissive spectral band structure, and the at least one fully-transmissive spectral band structure is randomly arranged with a plurality of polarization filter structures and a plurality of FP cavity structures.
In a nineteenth embodiment of the present invention, each period of the light splitting structure further includes at least one full-spectrum structure, the full-spectrum structure has no light splitting effect on the incident light, and full-spectrum information can be obtained for signal compensation of the spectrum filtering structure, especially when the light splitting structures are all FP cavity structures, the optical signals obtained by the image sensor are weaker, and by adding the full-spectrum structure to the light splitting structure, the signal-to-noise ratio of the image sensor can be improved, and the spectrum resolution capability of the handheld multispectral imager can be effectively improved.
As a twentieth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined as the above-described embodiment, wherein each period of the light splitting structure further includes at least one bandpass wide-spectrum filter structure, and the at least one bandpass wide-spectrum filter structure is randomly arranged with a plurality of polarization filter structures and a plurality of FP cavity structures. In the embodiment, a specific spectrum can be transmitted through a wide spectrum filtering range through reasonable design, so that the requirements of different application scenes are met.
As a twenty-first embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined as to the growth manner of the plurality of polarization filter structures on the basis of the above-described embodiment, in which the plurality of polarization filter structures are integrally deposited and grown on the pixel photosensitive unit 10. Through depositing and growing a plurality of polarization filter structure integral type on pixel sensitization unit 10, can reduce the volume of beam splitting layer, reduce the energy loss, improve firmness, preparation efficiency and integrated level, can effectively improve the spectral resolution ability of handheld multispectral imager.
As a twenty-second embodiment of the present invention, as shown in fig. 4, there is provided a handheld multispectral imager, which is further defined on the basis of the above-described embodiment, and in this embodiment, the handheld multispectral imager further includes an imaging lens group, a readout circuit and a control circuit, where the imaging lens group is configured to transmit light within a spectral range index of the handheld multispectral imager, and collect the transmitted light on the image sensor; the reading circuit is connected with the image sensor; the control circuit comprises a processor and a communication module, and the processor is respectively connected with the reading circuit and the communication module.
In a twenty-second embodiment of the present invention, the handheld multispectral imager uses the imaging lens group to transmit light within the spectrum range index of the handheld multispectral imager and collect the light on the image sensor, uses the readout circuit to read pixel data of the image sensor, uses the processor of the control circuit to perform image processing, and uses the communication module to transmit the final image processing result to the outside, thereby realizing acquisition of the spectrum image. The handheld multispectral imager provided by the embodiment has the advantages that the handheld multispectral imager has the advantages that gaps are not formed among the first cut-off filter film, the narrow-band filter film and the pixel photosensitive units, the spectral transmittance is high, the energy loss is reduced, the one-step preparation process is integrated into one piece, the handheld multispectral imager is not polluted by external environment, the firmness is better, the preparation efficiency and the integration level are higher, the quantum efficiency and the spectral transmittance are greatly improved, and the spectral resolution capability of the handheld multispectral imager can be effectively improved.
As a twenty-third embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined on the basis of the twenty-second embodiment, wherein the control circuit further includes a power supply module, which is respectively connected to the image sensor, the processor, and the communication module, to provide power support for the handheld multispectral imager.
As a twenty-fourth embodiment of the present invention, there is provided a handheld multispectral imager, which is further defined on the basis of the twenty-second embodiment, wherein the communication module is configurable as a wireless communication module, and the wireless communication module performs signal interaction with an external device. For example, the communication module can generate a Wifi hotspot to be connected with an external matched smart phone so as to transmit image signals and control information. In this particular embodiment, the human-machine interaction part is implemented by a smart phone through a dedicated APP. The special APP operated by the matched smart phone has the following functions: the handheld multispectral imager is connected to perform data interaction through the Wifi function of the mobile phone; the imaging human-computer interaction interface is provided, so that a spectrum image acquired by the handheld multispectral imager can be displayed in real time; the mobile phone image acquisition control is provided with an image acquisition control, and after clicking the image acquisition control, the current frame image can be stored in a mobile phone storage space; the method has the function of checking the specific spectrum, and only the image of the selected spectrum can be displayed after clicking to check the specific spectrum; the system has the function of checking the spectral reflectance curve at the specific position, and the spectral reflectance curve at the current position is displayed after clicking and checking the spectral reflectance curve at the specific position.
Spatially relative terms, such as "above … …," "above … …," "upper surface at … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations of "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present invention.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (13)
1. A handheld multispectral imager, the handheld multispectral imager comprising an image sensor, the image sensor comprising:
the pixel photosensitive unit (10), the said pixel photosensitive unit (10) is used for realizing the image acquisition and data readout;
the light splitting structure comprises a plurality of periods which are distributed periodically, each period comprises a narrow-band filter film (20), the narrow-band filter films (20) are integrally deposited and grown on the pixel photosensitive units (10), and the narrow-band filter films (20) are used for realizing the tunability of the central wavelength of a required wave band; the narrow-band filter film (20) comprises a plurality of FP cavity structures which are distributed in a mosaic manner;
a transition layer (40), the transition layer (40) being integrally deposited and grown on the light splitting structure;
the first cut-off filter film (30), the first cut-off filter film (30) is integrally deposited and grown on the transition layer (40), and the first cut-off filter film (30) is used for cutting off a first interference wave band; the transition layer (40) is used for transiting two film systems of the narrow-band filter film (20) and the first cut-off filter film (30);
A second cut-off filter film (60), the second cut-off filter film (60) being disposed on the first cut-off filter film (30), the second cut-off filter film (60) being configured to cut off a second interference band, the second interference band being different from the first interference band;
and a third cut-off filter film (70), wherein the third cut-off filter film (70) is arranged on the second cut-off filter film (60), and the third cut-off filter film (70) is used for cutting off a third interference wave band, and the third interference wave band is different from the first interference wave band and the second interference wave band.
2. According to claim 1The handheld multispectral imager is characterized in that the film system structure of the image sensor is Sub|H (LH) ≡S 1 2nL(HL)^S 1 H L n 1 (W1)^S 2 n 2 (W2)^S 3 n 3 (W3)^S 4 |Air，H(LH)^S 1 2nL(HL)^S 1 H is the film structure of the narrow band filter film (20), L is the film structure of the transition layer (40), W1, W2 and W3 each comprise a high refractive index material and a low refractive index material, n 1 (W1)^S 2 Is a film system structure of the first cut-off filter film (30), n 2 (W2)^S 3 Is a film system structure of the second cut-off filter film (60), n 3 (W3)^S 4 Is a film structure of the third stop filter film (70), H is a high refractive index material, L is a low refractive index material, S 1 、S 2 、S 3 And S is 4 For the number of overlapping times, n is the film thickness adjustment coefficient of the narrow-band filter film, n 1 For the film thickness adjustment coefficient, n, of the first cut-off filter film (30) 2 For the film thickness adjustment coefficient, n, of the second cut-off filter film (60) 3 And adjusting a coefficient for the film thickness of the third stop filter film (70).
3. The handheld multispectral imager of claim 1, wherein in the film system configuration of the first cut-off filter film (30), W1 comprises (0.5LH0.5L) or (0.5HL0.5H); in the second cut filter film (60), W2 includes (0.5LH0.5L) or (0.5HL0.5H); in the third stop filter film (70), W3 includes (0.5LH0.5L) or (0.5HL0.5H).
4. A hand-held multispectral imager according to any one of claims 1 to 3, wherein the first cut-off filter film (30), the second cut-off filter film (60) and the third cut-off filter film (70) are each prepared by alternating deposition of a high refractive index material and a low refractive index material, the high refractive index materials of the first cut-off filter film (30), the second cut-off filter film (60) and the third cut-off filter film (70) each comprise Ta 2 O 5 、Ti 3 O 5 、TiO 2 、Si 3 N 4 Or Nb (Nb) 2 O 5 The low refractive index materials of the first cut-off filter film (30), the second cut-off filter film (60) and the third cut-off filter film (70) each comprise SiO 2 、MgF 2 And Al 2 O 3 At least one of them.
5. The handheld multispectral imager of claim 1, wherein the second cutoff filter film (60) is adhesively disposed on the first cutoff filter film (30).
6. The handheld multispectral imager of claim 1, wherein the second cutoff filter film (60) is integrally deposited on the first cutoff filter film (30).
7. The handheld multispectral imager of claim 5 or 6, wherein the third cutoff filter film (70) is adhesively disposed on the second cutoff filter film (60).
8. The handheld multispectral imager of claim 6, wherein the third cutoff filter film (70) is integrally deposited on the second cutoff filter film (60).
9. The handheld multispectral imager of claim 1, wherein each cycle further comprises a plurality of polarization filtering structures having different polarization directions, the plurality of polarization filtering structures being randomly arranged with the plurality of FP cavity structures.
10. The handheld multispectral imager of claim 9, wherein each cycle comprises four polarization filtering structures having polarization angles of 0 °, 45 °, 90 ° and 135 °, respectively.
11. The handheld multispectral imager of claim 9, wherein each cycle further comprises at least one full-transmission spectral band structure, the at least one full-transmission spectral band structure being randomly arranged with the plurality of polarization filtering structures and the plurality of FP cavity structures.
12. The handheld multispectral imager of any one of claims 9 to 11, wherein each cycle further comprises at least one bandpass wide spectrum filter structure, the at least one bandpass wide spectrum filter structure being randomly arranged with the plurality of polarization filter structures and the plurality of FP cavity structures.
13. The handheld multispectral imager of claim 1, wherein the handheld multispectral imager further comprises:
the imaging lens group is used for transmitting light in the spectrum range index of the handheld multispectral imager and converging the transmitted light on the image sensor;
a readout circuit connected to the image sensor;
the control circuit comprises a processor and a communication module, and the processor is respectively connected with the reading circuit and the communication module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111208227.1A CN115993186A (en) | 2021-10-18 | 2021-10-18 | Hand-held multispectral imager |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111208227.1A CN115993186A (en) | 2021-10-18 | 2021-10-18 | Hand-held multispectral imager |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115993186A true CN115993186A (en) | 2023-04-21 |
Family
ID=85992605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111208227.1A Pending CN115993186A (en) | 2021-10-18 | 2021-10-18 | Hand-held multispectral imager |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115993186A (en) |
-
2021
- 2021-10-18 CN CN202111208227.1A patent/CN115993186A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Geelen et al. | A compact snapshot multispectral imager with a monolithically integrated per-pixel filter mosaic | |
| CN107271039B (en) | Compact miniature fast illuminated spectral imaging detecting device and detection method | |
| CN108897088B (en) | Preparation method of all-dielectric ultrathin two-dimensional circular polarization dichroism device | |
| JP6194592B2 (en) | Spectroscopic camera | |
| CN110017897B (en) | Compact monocular multichannel combined multispectral imaging system | |
| CN103412407A (en) | Multi-spectrum image collecting system | |
| CN203164522U (en) | Multispectral image acquisition system | |
| CN102419209B (en) | Handheld thermal infrared imager | |
| CN204963859U (en) | Remote sensing parameter camera | |
| CN117641139A (en) | Spectral sensor system using an optical filter sub-array | |
| CN117321394A (en) | High-precision quick-irradiation multispectral imaging system and method based on multipath illumination | |
| CN109686806A (en) | The spectral detector device and preparation method that a kind of visible light to near-infrared integrates | |
| KR20220113513A (en) | Image Sensors, Spectral Segmentation and Filtering Devices, and Methods for Manufacturing Image Sensors | |
| CN106291895B (en) | A kind of double-colored prior-warning device of wide field staring type infrared and ultraviolet | |
| US11092489B2 (en) | Wide-angle computational imaging spectroscopy method and apparatus | |
| US8760494B1 (en) | UV detection of objects hidden in foliage | |
| Sassoon et al. | Flare in interference-based hyperspectral cameras | |
| CN115993186A (en) | Hand-held multispectral imager | |
| CN109781260B (en) | Ultra-compact snapshot type polarization spectrum imaging detection device and detection method | |
| CN115993329A (en) | Handheld multispectral imager | |
| CN207717226U (en) | Hyperspectral imaging devices based on periodically interference membrane system FP chambers scanning | |
| CN209639829U (en) | A kind of push-scanning type polarization light spectrum image-forming micro-system | |
| CN210953797U (en) | Analytical equipment based on multiband filtering and beauty instrument and vanity mirror of using thereof | |
| US20230145952A1 (en) | Hyperspectral Imaging Device | |
| CN114689174A (en) | Chip-level multispectral camera system and operation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |