CN110811615A - Terahertz imaging method and device based on spiral phase contrast imaging - Google Patents
Terahertz imaging method and device based on spiral phase contrast imaging Download PDFInfo
- Publication number
- CN110811615A CN110811615A CN201911152101.XA CN201911152101A CN110811615A CN 110811615 A CN110811615 A CN 110811615A CN 201911152101 A CN201911152101 A CN 201911152101A CN 110811615 A CN110811615 A CN 110811615A
- Authority
- CN
- China
- Prior art keywords
- lens
- terahertz
- imaging
- transmission
- plane
- 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
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/0507—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves using microwaves or terahertz waves
Landscapes
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Radiology & Medical Imaging (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Physics & Mathematics (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
A terahertz imaging method and device based on spiral phase contrast imaging are disclosed, wherein the terahertz imaging method comprises the steps that a collimated terahertz wave beam is transmitted by a target to obtain a first transmission wave beam; after the first transmission beam propagation distance f is modulated by a first lens, a second transmission beam is obtained; after the propagation distance f of the second transmission wave beam is modulated by a spiral phase plate positioned on the frequency spectrum plane, a third transmission wave beam is obtained; after the third transmission beam propagation distance f is modulated by a second lens, a fourth transmission beam is obtained; and the fourth transmission beam is received by the terahertz camera after the propagation distance f and then is imaged. According to the terahertz high-contrast imaging method, a spiral phase-contrast imaging technology is introduced into terahertz imaging, and the characteristic of high-contrast imaging can be realized by combining spiral phase-contrast imaging, so that terahertz high-contrast imaging is realized.
Description
Technical Field
The invention relates to the technical field of terahertz quasi-optical imaging, in particular to a terahertz imaging method and device based on spiral phase contrast imaging.
Background
The terahertz wave has certain penetrating capacity to biological tissues, has low single photon energy, cannot cause biological tissue ionization, and is very safe in biomedical imagingAnd is suitable for biomedical imaging. However, the contrast of terahertz biomedical images is often very low, mainly because the water content of biological tissues is high, the terahertz waves are absorbed by water very strongly, and the difference between the transmission/reflection rates of some different types of biological tissues to terahertz waves is very small. Therefore, there is a need to study terahertz high-contrast imaging methods. Helical phase contrast imaging is widely used in optical imaging by combining an imaging objective function with a phase factor, as opposed to conventional imaging methods
And performing convolution operation to enable pixels of a uniform area in the target image to become 0, and enabling boundaries of areas with different intensities or phases to be protruded, thereby realizing imaging contrast enhancement. The spiral phase contrast imaging technology is introduced into the terahertz imaging field, and terahertz high-contrast imaging can be achieved. Therefore, the method for researching the terahertz spiral phase-contrast imaging has important research value.
Disclosure of Invention
In view of the above, it is a primary objective of the present invention to provide a terahertz imaging method and apparatus based on spiral phase contrast imaging, so as to at least partially solve at least one of the above technical problems.
In order to achieve the above object, as one aspect of the present invention, there is provided a terahertz imaging method based on spiral phase contrast imaging, including:
obtaining a first transmission beam after the collimated terahertz beam is transmitted by a target;
after the first transmission beam propagation distance f is modulated by a first lens, a second transmission beam is obtained;
after the propagation distance f of the second transmission wave beam is modulated by a spiral phase plate positioned on the frequency spectrum plane, a third transmission wave beam is obtained;
after the third transmission beam propagation distance f is modulated by a second lens, a fourth transmission beam is obtained;
and the fourth transmission beam is received by the terahertz camera after the propagation distance f and then is imaged.
As another aspect of the present invention, there is also provided an imaging apparatus for performing the terahertz imaging method as described above, including:
a first lens for modulating a first transmitted beam transmitted through an imaging target;
a helical phase plate for modulating the second transmitted beam passing through the first lens;
a second lens for modulating the third transmitted beam passing through the spiral phase plate; and
and the terahertz camera is used for receiving and imaging the fourth transmission beam after passing through the second lens.
Based on the technical scheme, compared with the prior art, the terahertz imaging method and device based on the spiral phase contrast imaging have at least one of the following advantages:
1. the terahertz high-contrast imaging method based on the spiral phase contrast imaging introduces the spiral phase contrast imaging technology into terahertz imaging, and combines the characteristic that the spiral phase contrast imaging can realize high-contrast imaging, thereby realizing terahertz high-contrast imaging;
2. the terahertz camera is used for receiving, and real-time imaging of an imaging target can be achieved.
Drawings
FIG. 1 is a schematic step diagram of a terahertz high-contrast imaging method based on helical phase contrast imaging according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an optical path structure of a terahertz high-contrast imaging device based on spiral phase contrast imaging according to an embodiment of the present invention;
FIG. 3 is a simulation imaging result diagram of the terahertz high-contrast imaging method based on the spiral phase-contrast imaging in the embodiment of the present invention.
Detailed Description
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
At present, most of the traditional terahertz biomedical imaging methods have low imaging contrast and poor imaging quality. The invention aims to helix in optical imagingPhase contrast imaging is introduced into terahertz imaging to improve imaging contrast. Compared with the traditional imaging method, the spiral phase contrast imaging method is realized by combining an imaging objective function and a phase factor
And performing convolution operation to enable pixels of a uniform area in the target image to become 0, and enabling boundaries of areas with different intensities or phases to be protruded, thereby realizing imaging contrast enhancement. The terahertz camera is used as receiving in the imaging system, and real-time high-contrast imaging of the target can be realized. Because the terahertz wavelength is much longer than the optical wavelength, a strong diffraction effect is easy to occur, and therefore the size and the spacing of the elements of the experimental system are far larger than the wavelength.
The invention discloses a terahertz imaging method based on spiral phase contrast imaging, which comprises the following steps:
obtaining a first transmission beam after the collimated terahertz beam is transmitted by a target;
after the first transmission beam propagation distance f is modulated by a first lens, a second transmission beam is obtained;
after the propagation distance f of the second transmission wave beam is modulated by a spiral phase plate positioned on the frequency spectrum plane, a third transmission wave beam is obtained;
after the third transmission beam propagation distance f is modulated by a second lens, a fourth transmission beam is obtained;
and the fourth transmission beam is received by the terahertz camera after the propagation distance f and then is imaged.
The first lens and the second lens are both convex lenses, and the focal lengths of the first lens and the second lens are both f.
Wherein a field distribution E of a starting position of the first transmission beam1(x1，y1) Comprises the following steps:
E1(x1，y1)＝E0(x1，y1)t(x1，y1)；
wherein E is0(x1，y1) For a collimated terahertz field distribution to illuminate a target, t (x)1，y1) Is transmission of the objectFunction (x)1，y1) Are the coordinates of the target plane.
Wherein a field distribution E of the first transmitted beam reaching the first lens2(x2，y2) Satisfies the following conditions:
F{E2(x2，y2)}＝F{E1(x1，y1)}H(fx，fy)；
wherein F {. is Fourier transform,
fx＝x2/λf，fy＝y2λ f, j is an imaginary unit, λ is a terahertz wave wavelength, (x)2，y2) Is the coordinate of the plane of the first lens.
Wherein the field distribution E of the second transmitted beam arriving at said spectral plane3(x3，y3) Comprises the following steps:
wherein k is a wave number,
is the modulation function of the first lens, (x)3，y3) Are coordinates of the spectral plane.
Wherein a third transmitted beam field distribution E reaching the second lens4(x4，y4) Comprises the following steps:
wherein the content of the first and second substances,
is the modulation function of the helical phase plate,
is a square of a frequency spectrum planeAngle of orientation, fx＝x4/λf，fy＝y4/λf，(x4，y4) Is the coordinate of the plane of the second lens, p is (x)4，y4) The radial length of the plane, R, is the radius of the helical phase plate.
Wherein the field distribution of the terahertz camera surface E4(x4，y4) Comprises the following steps:
wherein (x)5，y5) Coordinates of a plane where the terahertz camera is located;
the fourier transform in the above equation can be written as,
wherein, Jm(. H) is a Bessel function of order m, Hm(. cndot.) is a Stereuf function of order m.
The invention also discloses an imaging device for executing the terahertz imaging method, which comprises the following steps:
a first lens for modulating a first transmitted beam transmitted through an imaging target;
a helical phase plate for modulating the second transmitted beam passing through the first lens;
a second lens for modulating the third transmitted beam passing through the spiral phase plate; and
and the terahertz camera is used for receiving and imaging the fourth transmission beam after passing through the second lens.
The imaging target, the first lens, the spiral phase plate, the second lens and the terahertz camera are arranged in parallel at equal intervals.
The distance between the imaging target, the first lens, the spiral phase plate, the second lens and the terahertz camera is f.
The technical solution of the present invention is further illustrated by the following specific embodiments in conjunction with the accompanying drawings. It should be noted that the following specific examples are given by way of illustration only and the scope of the present invention is not limited thereto.
As shown in fig. 1 and fig. 2, the terahertz high-contrast imaging method based on spiral phase contrast imaging of the present embodiment includes the following steps:
and S1, obtaining a first transmission beam after the collimated terahertz beam is transmitted by the target.
The field distribution of the starting position of the first transmitted beam is:
E1(x1，y1)＝E0(x1，y1)t(x1，y1)；
wherein E is0(x1，y1) For a collimated terahertz field distribution to illuminate a target, t (x)1，y1) As a transmission function of the object, (x)1，y1) Are the coordinates of the target plane.
S2, the first transmitted beam travels a distance f before reaching the first lens.
The first transmitted beam field distribution reaching the first lens satisfies:
F{E2(x2，y2)}＝F{E1(x1，y1)}H(fx，fy)；
wherein F {. is Fourier transform,
fx＝x2/λf，fy＝y2λ f, j is an imaginary unit, λ is a terahertz wave wavelength, f is a propagation distance, (x)2，y2) Is the coordinate of the plane of the first lens.
And S3, the first transmission beam is modulated by the first lens, and then reaches the spectrum surface by the propagation distance f.
The first transmission beam is modulated by the first lens to obtain a second transmission beam;
the second transmitted beam field distribution to the spectral plane is:
wherein k is a wave number,
is the modulation function of the first lens, (x)3，y3) Are coordinates of the spectral plane.
And S4, the second transmission beam is modulated by a spiral phase plate on the frequency spectrum plane and reaches the second lens by a propagation distance f.
And the second transmission beam is modulated by a spiral phase plate positioned on the frequency spectrum plane to obtain a third transmission beam. The third transmitted beam field distribution reaching the second lens is:
wherein the content of the first and second substances,is the modulation function of the helical phase plate,
is the azimuth angle of the spectral plane, fx＝x4/λf，fy＝y4/λf，(x4，y4) Is the coordinate of the plane of the second lens, p is (x)4，y4) The radial length of the plane, R, is the radius of the helical phase plate.
S5, the third transmission beam is modulated by the second lens, and then the transmission distance f is received by the terahertz camera. And the third transmission beam is modulated by the second lens to obtain a fourth transmission beam.
The field distribution of the fourth transmission beam reaching the surface of the terahertz camera is as follows:
wherein (x)5，y5) Is a plane on which the terahertz camera is positionedThe coordinates of (a).
The fourier transform in the above equation can be written as,
wherein, Jm(. H) is a Bessel function of order m, Hm(. cndot.) is a Stereuf function of order m.
The convolution of the target function t and exp (j phi) in the field distribution expression of the surface of the terahertz camera causes that pixel points in a uniform area in a target image are replaced by 0, and boundaries of different strength or phase areas are highlighted, so that high-contrast imaging is realized.
Fig. 3 shows simulation results, in which fig. 3 (a), (c), and (e) show simulation targets, respectively, in which the transmittances of the letters "THz" in the target image are all 1, and the transmittances of the background are 0.6, 0.9, and 0.99, respectively, according to the contrast calculation formula: (max-min)/(max + min) it can be seen that the contrast of the target image is 25%, 5.26%, 0.5% respectively, i.e. the contrast is reduced accordingly, when the contrast is 0.5%, the human eye cannot recognize the target; (b) the images (a), (d), (f) and (e) are the corresponding images (a), (c) and (e) terahertz helical phase contrast imaging simulation results, and it can be seen that the simulation results can better extract the high-frequency information of the target, and the contrast of the three images is 100%, so that high-contrast imaging of the low-contrast target is realized.
In this embodiment, the first lens and the second lens are both convex lenses, and the focal lengths of the first lens and the second lens are both f. The purpose of the first lens is to fourier transform and then filter the terahertz beam containing the target information in the spectral plane. The spiral phase contrast imaging adds a spiral phase plate on a frequency spectrum surface, filters low-frequency components through phase modulation filtering, and highlights high-frequency components. The purpose of the second lens is to perform fourier transformation on the filtered beam at the spectral plane to restore the filtered image of the target.
In conclusion, the terahertz high-contrast imaging method based on the spiral phase contrast imaging can realize high-contrast imaging, and real-time imaging can be realized by adopting the terahertz camera as receiving.
Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. In particular, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Generally, the expression is meant to encompass variations of ± 10% in some embodiments, 5% in some embodiments, 1% in some embodiments, 0.5% in some embodiments by the specified amount.
Furthermore, "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.
The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A terahertz imaging method based on spiral phase contrast imaging comprises the following steps:
obtaining a first transmission beam after the collimated terahertz beam is transmitted by a target;
after the first transmission beam propagation distance f is modulated by a first lens, a second transmission beam is obtained;
after the propagation distance f of the second transmission wave beam is modulated by a spiral phase plate positioned on the frequency spectrum plane, a third transmission wave beam is obtained;
after the third transmission beam propagation distance f is modulated by a second lens, a fourth transmission beam is obtained;
and the fourth transmission beam is received by the terahertz camera after the propagation distance f and then is imaged.
2. The terahertz imaging method of claim 1,
the first lens and the second lens are both convex lenses, and the focal lengths of the first lens and the second lens are both f.
3. The terahertz imaging method of claim 1,
field distribution E of the starting position of the first transmission beam1(x1，y1) Comprises the following steps:
E1(x1，y1)＝E0(x1，y1)t(x1，y1)；
wherein E is0(x1，y1) For a collimated terahertz field distribution to illuminate a target, t (x)1，y1) As a transmission function of the object, (x)1，y1) Are the coordinates of the target plane.
4. The terahertz imaging method according to claim 3,
field distribution E of the first transmitted beam reaching the first lens2(x2，y2) Satisfies the following conditions:
F{E2(x2，y2)}＝F{E1(x1，y1)}H(fx，fy)；
wherein F {. is Fourier transform,
fx＝x2/λf，fy＝y2λ f, j is an imaginary unit, λ is a terahertz wave wavelength, (x)2，y2) Is the coordinate of the plane of the first lens.
5. The terahertz imaging method according to claim 4,
field distribution E of the second transmitted beam reaching said spectral plane3(x3，y3) Comprises the following steps:
wherein k is a wave number,
is the modulation function of the first lens, (x)3，y3) Are coordinates of the spectral plane.
6. The terahertz imaging method according to claim 5,
a third transmitted beam field distribution E to the second lens4(x4，y4) Comprises the following steps:
wherein the content of the first and second substances,
is the modulation function of the helical phase plate,
is the azimuth angle of the spectral plane, fx＝x4/λf，fy＝y4/λf，(x4，y4) Is the coordinate of the plane of the second lens, p is (x)4，y4) The radial length of the plane, R, is the radius of the helical phase plate.
7. The terahertz imaging method according to claim 6,
field distribution E of the terahertz camera surface4(x4，y4) Comprises the following steps:
wherein (x)5，y5) Coordinates of a plane where the terahertz camera is located;
the fourier transform in the above equation can be written as,
wherein, Jm(. H) is a Bessel function of order m, Hm(. cndot.) is a Stereuf function of order m.
8. An imaging apparatus for performing the terahertz imaging method according to any one of claims 1 to 7, comprising:
a first lens for modulating a first transmitted beam transmitted through an imaging target;
a helical phase plate for modulating the second transmitted beam passing through the first lens;
a second lens for modulating the third transmitted beam passing through the spiral phase plate; and
and the terahertz camera is used for receiving and imaging the fourth transmission beam after passing through the second lens.
9. The imaging apparatus according to claim 8,
the imaging target, the first lens, the spiral phase plate, the second lens and the terahertz camera are arranged in parallel at equal intervals.
10. The imaging apparatus according to claim 9,
the distance between the imaging target, the first lens, the spiral phase plate, the second lens and the terahertz camera is f.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911152101.XA CN110811615A (en) | 2019-11-20 | 2019-11-20 | Terahertz imaging method and device based on spiral phase contrast imaging |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911152101.XA CN110811615A (en) | 2019-11-20 | 2019-11-20 | Terahertz imaging method and device based on spiral phase contrast imaging |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110811615A true CN110811615A (en) | 2020-02-21 |
Family
ID=69557954
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911152101.XA Pending CN110811615A (en) | 2019-11-20 | 2019-11-20 | Terahertz imaging method and device based on spiral phase contrast imaging |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110811615A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111505629A (en) * | 2020-05-08 | 2020-08-07 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015163912A (en) * | 2014-02-28 | 2015-09-10 | 国立大学法人 千葉大学 | Optical vortex generator, continuous spiral phase plate used therefor, and optical vortex generation method |
| CN106533574A (en) * | 2016-12-26 | 2017-03-22 | 华中科技大学 | Demodulation device and method for terahertz vortex beam orbit angular momentum state |
| US20180284025A1 (en) * | 2017-03-31 | 2018-10-04 | Richard Gozali | Oam microscope for edge enhancement of biomedical and condensed matter samples and objects |
| CN108780042A (en) * | 2016-01-13 | 2018-11-09 | 尼克根合伙Ip有限责任公司 | System and method for multi-parameter spectrum |
| CN109212749A (en) * | 2018-07-09 | 2019-01-15 | 苏州大学 | A kind of filter plate and its design method for realizing edge enhancing imaging |
-
2019
- 2019-11-20 CN CN201911152101.XA patent/CN110811615A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015163912A (en) * | 2014-02-28 | 2015-09-10 | 国立大学法人 千葉大学 | Optical vortex generator, continuous spiral phase plate used therefor, and optical vortex generation method |
| CN108780042A (en) * | 2016-01-13 | 2018-11-09 | 尼克根合伙Ip有限责任公司 | System and method for multi-parameter spectrum |
| CN106533574A (en) * | 2016-12-26 | 2017-03-22 | 华中科技大学 | Demodulation device and method for terahertz vortex beam orbit angular momentum state |
| US20180284025A1 (en) * | 2017-03-31 | 2018-10-04 | Richard Gozali | Oam microscope for edge enhancement of biomedical and condensed matter samples and objects |
| CN109212749A (en) * | 2018-07-09 | 2019-01-15 | 苏州大学 | A kind of filter plate and its design method for realizing edge enhancing imaging |
Non-Patent Citations (3)
| Title |
|---|
| HUI LIU: "Study on the Terahertz Vortex Imaging based on Spiral Phase Plates", 《2019 44TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ)》 * |
| 刘婷婷: "基于螺旋相位滤波的共路相移数字全息术", 《光电子 激光》 * |
| 王炯: "螺旋相位板参数对螺旋相衬成像系统性能影响研究", 《光学学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111505629A (en) * | 2020-05-08 | 2020-08-07 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
| CN111505629B (en) * | 2020-05-08 | 2021-02-02 | 中国科学院国家空间科学中心 | Terahertz security inspection imaging system and method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Anand et al. | Single-shot mid-infrared incoherent holography using Lucy-Richardson-Rosen algorithm | |
| US10401294B2 (en) | OAM microscope for edge enhancement of biomedical and condensed matter samples and objects | |
| Levin et al. | 4D frequency analysis of computational cameras for depth of field extension | |
| CN105204311B (en) | A kind of optical scanner holography edge detection method based on Gauss apodization | |
| CN108873323B (en) | Method and system for realizing edge enhanced imaging | |
| CN104007559A (en) | Foveated imaging system with partial super-resolution scanning function | |
| CN109187434B (en) | Reflective scattering imaging device and imaging method using same | |
| CN110811615A (en) | Terahertz imaging method and device based on spiral phase contrast imaging | |
| Dubey et al. | High-resolution imaging system with an annular aperture of coded phase masks for endoscopic applications | |
| Carles et al. | Phase mask selection in wavefront coding systems: A design approach | |
| CN109716387B (en) | Image processing apparatus and method | |
| JP6124518B2 (en) | Image processing apparatus, operation method of image processing apparatus, and image processing program | |
| Liu et al. | Underwater image transmission and blurred image restoration | |
| CN110793943A (en) | Reflection type terahertz imaging method and device based on spiral phase contrast imaging | |
| CN106092318B (en) | A kind of total-reflection type broadband multi-optical spectrum imaging system | |
| CN109993703A (en) | Multi-scale image noise-reduction method and device | |
| CN110823832A (en) | Terahertz imaging method and device based on dark field imaging | |
| Vila-Francés et al. | Improving the performance of acousto-optic tunable filters in imaging applications | |
| CN117288720A (en) | Non-invasive Shan Zhenkuan spectrum scattering imaging system and imaging method based on subarea homogenization | |
| CN109212749B (en) | Filter plate for realizing edge enhanced imaging and design method thereof | |
| CN110849841A (en) | Dark field imaging-based reflective terahertz imaging method and device | |
| EP0244640B1 (en) | Light-modulating microscope using deconvolution | |
| Zhou et al. | Inverse sinusoidal phase mask to extend the depth of field of incoherent imaging systems | |
| JP4982300B2 (en) | Object photographing method and apparatus | |
| Matei et al. | Circular IIR filter design and applications in biomedical image analysis |
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 | ||
| WD01 | Invention patent application deemed withdrawn after publication | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20200221 |