CN116560203A - Digital holographic speckle suppression imaging system based on random microlens array - Google Patents
Digital holographic speckle suppression imaging system based on random microlens array Download PDFInfo
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- CN116560203A CN116560203A CN202310666314.4A CN202310666314A CN116560203A CN 116560203 A CN116560203 A CN 116560203A CN 202310666314 A CN202310666314 A CN 202310666314A CN 116560203 A CN116560203 A CN 116560203A
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- 238000003384 imaging method Methods 0.000 title claims abstract description 24
- 230000001629 suppression Effects 0.000 title claims abstract description 12
- 239000000758 substrate Substances 0.000 claims description 7
- 238000013461 design Methods 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- 230000003287 optical effect Effects 0.000 claims description 3
- 238000003491 array Methods 0.000 claims description 2
- 238000001093 holography Methods 0.000 description 14
- 238000000034 method Methods 0.000 description 14
- 238000012545 processing Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000001914 filtration Methods 0.000 description 3
- 238000005286 illumination Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000002059 diagnostic imaging Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 238000013041 optical simulation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0443—Digital holography, i.e. recording holograms with digital recording means
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/48—Laser speckle optics
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/04—Processes or apparatus for producing holograms
- G03H1/0486—Improving or monitoring the quality of the record, e.g. by compensating distortions, aberrations
Abstract
The invention relates to a digital holographic speckle suppression imaging system based on a random microlens array. The laser generates a laser beam, and the laser beam is divided into a reference beam and an object beam through a beam splitting prism; the objective lens and the convex lens adjust the reference beam to expand the reference beam and convert the reference beam into a parallel beam, and the reflector changes the propagation direction of the reference beam into a vertical direction; the object light beam changes its propagation direction into the horizontal direction through the reflector, the object light beam is expanded by the objective lens, the height of the random microlens array and the motor is adjusted, the object light beam is made to strike at the edge part of the surface of the random microlens array, the convex lens makes the light beam parallel, the reference light beam and the object light beam are combined by the beam combining prism through the sample object, and the interference pattern is recorded by the interference light irradiation on the CCD camera. The device can effectively inhibit speckle noise of a digital holographic system through rotation of the random microlens array, and improve signal to noise ratio.
Description
Technical Field
The invention relates to a digital holographic speckle suppression imaging system and method based on a random microlens array, and belongs to the field of digital holography.
Background
The development of digital holography has provided us with a more advanced imaging technique that helps to study and understand the structure and behaviour of objects in depth. Digital holography has become a fairly mature topic covering a wide range of fields. The method has wide application in the fields of scientific research, medical imaging, industrial detection, virtual reality and the like. It can be used for three-dimensional morphological analysis, object reconstruction, motion tracking, optical encryption and other applications.
Digital holography realizes more convenient and efficient holographic imaging by digitizing light wave information of an object and by means of the computing and processing capabilities of a computer. Digital holography no longer requires the use of a conventional holographic film, but rather stores the light wave information in the form of digital data in a computer. The reconstruction and real-time display of the holographic image can be realized by utilizing a digital image processing algorithm and an optical simulation technology.
Digital holography has a wide range of applications in many fields including three-dimensional displays, holographic storage, holographic communications, and the like. The method provides new possibility for realizing more realistic and high-quality stereoscopic images, and provides a technical foundation for the development of the fields of virtual reality, augmented reality and the like. Meanwhile, digital holography has great potential in the fields of medicine, material science, safety anti-counterfeiting and the like.
In general, digital holography is an extension and development of conventional holography, and by means of the progress of digital technology, digitization and computerization of holographic imaging are realized, thus bringing new possibilities for imaging and display technologies in various fields.
However, the digital holographic imaging system adopts coherent light illumination, and the speckle noise has a great influence on the imaging capability, resolution and other factors of the system. The digital image processing, filtering and other methods are adopted, so that the image quality and resolution can be influenced. And a series of images with different speckle noise backgrounds are recorded and reproduced, the speckle noise contrast can be obviously reduced by a multi-step superposition method, the signal to noise ratio of the system is improved, and the requirements of three-dimensional high-resolution observation are met.
The problem of speckle in digital holography is a phenomenon common in holographic imaging that affects the quality and sharpness of the reconstructed image. The background of resolving the speckle problem can help us understand its cause and the targeted solution. Speckle is a phenomenon caused by interference and diffraction effects of light. In digital holography, when a laser or light source is irradiated onto a recorded object, the light waves interact with minute non-uniformities of the object surface, resulting in a spatial variation of the light intensity. The change of the light intensity is presented as problems of uneven brightness, noise, blurring and the like when reconstructing the holographic image, and the definition and quality of the image are reduced.
The speckle problem exists in conventional holography and continues in digital holography. Speckle is generated by light coherence, roughness of the object surface, wavelength of the light source, and the like. When a light wave passes through an uneven object surface, it diffracts and interferes, resulting in a change in local light intensity. These light intensity variations can manifest themselves as unwanted effects of interference fringes, speckle, noise, etc. during reconstruction of the holographic image.
To address the problem of speckle, researchers have proposed various methods and techniques. One common approach is to suppress speckle noise by using spatial filtering techniques. The filtering techniques can adjust the light intensity in the reconstruction process of the holographic image, and reduce the influence of speckle. In addition, the influence of speckle can be effectively reduced by adopting the techniques of multi-angle recording, multi-wavelength illumination and the like. Furthermore, mathematical models and image processing algorithms are also applied to model and correct speckle.
Overall, the speckle problem is one of the challenges common in digital holography. The digital holographic speckle suppression imaging system based on the random microlens array can improve the quality and definition of digital holographic images and improve the holographic imaging effect and the application reliability.
Disclosure of Invention
In order to solve the influence of speckle noise in the digital holographic imaging process, the invention provides a digital holographic speckle suppression imaging system and method based on a random microlens array. The device can effectively inhibit speckle noise of a digital holographic system through rotation of the random microlens array, and improves signal to noise ratio.
In order to achieve the above purpose, the present invention is realized by the following technical scheme: the device comprises a laser 1, a beam splitting prism 2, an objective lens 3, a convex lens 4, a reflecting mirror 5, a reflecting mirror 6, an objective lens 7, a random micro lens array 8, a motor 9, a convex lens 10, a sample object 11, a beam combining prism 12 and a CCD camera 13; the laser 1 generates a laser beam, and the laser beam is divided into a reference beam and an object beam through the beam splitting prism 2; the objective lens 3 and the convex lens 4 adjust the reference beam to expand the reference beam and convert the reference beam into a parallel beam, and the reflector 5 changes the propagation direction of the reference beam into a vertical direction; the object light beam changes its propagation direction to the horizontal direction through the reflector 6, the object light beam is expanded by the objective lens 7, the heights of the random microlens array 8 and the motor 9 are adjusted, the object light beam is made to strike at the edge part of the surface of the random microlens array 8, the convex lens 10 makes the beam parallel, the reference beam and the object light beam are combined through the sample object 11, the beam combining prism 12 irradiates the interference pattern on the CCD camera 13, and the interference pattern is recorded.
Further, the random microlens array 8 is formed by randomly arranging a plurality of quadrilateral microlenses, pentagonal microlenses and hexagonal microlenses on a circular glass substrate; each micro lens is an ellipsoid, the radius of each micro lens is 2mm, the thickness of each micro lens is 0.3mm, the bottom of each micro lens is provided with a round glass substrate with the diameter of 56mm, and the thickness of each micro lens is 0.2mm; the thickness of the entire microlens array was 0.5mm.
Further, a through hole is arranged in the center of the random microlens array 8, the diameter of the through hole is 2mm, the through hole is connected with the shaft of the motor 9, and the through hole is driven by the motor to rotate.
Further, a random microlens array 8 is placed in the object light path between the objective lens 7 and the convex lens 10; the random microlens array 8 serves as a diffuser, plays a role in homogenizing light, and can effectively suppress speckle noise in a digital holographic system.
Further, for the design of the random microlens array, the method comprises the following steps: creating a reference plane for locating the position of the microlens; randomly generating a group of points on a reference plane to serve as the center of the micro lens; for each point, creating a micro lens at a corresponding position according to preset parameters; the micro lens is an ellipsoid; finally, a round substrate is generated under the micro lens, and a through hole with the diameter of 2mm is arranged in the center.
Compared with the prior art, the invention has the following obvious progress: the device drives the random microlens array to rotate through the motor, and can obviously inhibit speckle noise of a digital holographic imaging system. In the aspect of signal processing, a digital holographic algorithm is adopted, so that speckle noise can be fully restrained in the aspect of image reproduction, and the signal-to-noise ratio of the system is improved. The spectrum analysis can effectively concentrate the spectrum, and the purpose of speckle noise reduction is further achieved.
Drawings
Fig. 1 is a schematic view of the optical path of an imaging system of the present invention.
Fig. 2 is a schematic diagram of a random microlens array according to the present invention.
FIG. 3 is a schematic diagram of the random microlens array and motor assembly of the present invention.
In the figure: 1. a laser; 2. a beam-splitting prism; 3. an objective lens; 4. a convex lens; 5. a reflecting mirror; 6. a reflecting mirror; 7. an objective lens; 8. a random microlens array; 9. a motor; 10. a convex lens; 11. a sample object; 12. a beam combining prism; 13. CCD camera.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear and obvious, the invention is further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are to be considered in an illustrative sense only and are not intended to limit the invention.
As shown in fig. 1, a holographic speckle suppression imaging system based on random microlens column numbers is characterized in that: the device comprises a laser 1, a beam splitting prism 2, an objective lens 3, a convex lens 4, a reflecting mirror 5, a reflecting mirror 6, an objective lens 7, a random micro lens array 8, a motor 9, a convex lens 10, a sample object 11, a beam combining prism 12 and a CCD camera 13. The laser 1 generates a laser beam, and the laser beam is divided into a reference beam and an object beam through the beam splitting prism 2; the objective lens 3 and the convex lens 4 adjust the reference beam to expand the reference beam and convert the reference beam into a parallel beam, and the reflector 5 changes the propagation direction of the reference beam into a vertical direction; the object light beam changes its propagation direction to the horizontal direction through the reflector 6, the object light beam is expanded by the objective lens 7, the heights of the random microlens array 8 and the motor 9 are adjusted, the object light beam is made to strike at the edge part of the surface of the random microlens array 8, the convex lens 10 makes the beam parallel, the reference beam and the object light beam are combined through the sample object 11, the beam combining prism 12 irradiates the interference pattern on the CCD camera 13, and the interference pattern is recorded.
As shown in fig. 1, a digital holographic speckle suppression imaging system based on a random microlens array comprises the following adjustment steps: the horizontal central axes of the beam splitting prism 2, the objective lens 3, the convex lens 4 and the reflecting mirror 5 are on the same horizontal straight line with the central axis of the light beam emitted by the laser 1, and the reflecting mirror 5 forms 45 degrees with the horizontal axis; the reflecting mirror 6 is in the vertical direction of the splitting prism 2; the horizontal central axes of the reflector 6, the objective lens 7, the convex lens 10, the sample object 11, the beam combining prism 12 and the CCD camera 13 are positioned on the same horizontal line, and the reflector forms 45 degrees with the horizontal axis; the object light beam is expanded through the objective lens 7, the distance between the random microlens array 8 and the objective lens 7 is fully adjusted, and the object light beam strikes the edge part of the surface of the random microlens array.
As shown in fig. 2, a structure diagram of a random microlens array is characterized in that: for the design of random microlens arrays, comprising the steps of: creating a reference plane for locating the position of the microlens; randomly generating a group of points on a reference plane to serve as the center of the micro lens; for each point, creating a micro lens at a corresponding position according to preset parameters; the micro lens is an ellipsoid; finally, a round substrate is generated under the micro lens, and a through hole with the diameter of 2mm is arranged in the center.
As shown in fig. 3, an assembly schematic diagram of a random microlens array and a motor is characterized in that: the center of the random microlens array is provided with a hole with the diameter of 2mm, the shaft of the motor is 2mm, and the assembling mode is shown in the figure.
Claims (5)
1. A digital holographic speckle suppression imaging system based on a random microlens array is characterized in that: the device comprises a laser (1), a beam splitting prism (2), an objective lens (3), a convex lens (4), a reflecting mirror (5), a reflecting mirror (6), an objective lens (7), a random micro lens array (8), a motor (9), a convex lens (10), a sample object (11), a beam combining prism (12) and a CCD camera (13); the laser (1) generates a laser beam, and the laser beam is divided into a reference beam and an object beam through the beam splitting prism (2); the objective lens (3) and the convex lens (4) adjust the reference beam to expand the reference beam and convert the reference beam into a parallel beam, and the reflecting mirror (5) changes the propagation direction of the reference beam into a vertical direction; the object light beam changes the propagation direction of the object light beam into the horizontal direction through the reflecting mirror (6), the object light beam is expanded by the objective lens (7), the heights of the random micro lens array (8) and the motor (9) are adjusted, the object light beam is made to strike at the edge part of the surface of the random micro lens array (8), the convex lens (10) makes the beam parallel, the reference beam and the object light beam are combined through the sample object (11), and the interference pattern is recorded on the CCD camera (13) by the interference light irradiation.
2. The random microlens array digital holographic speckle suppression imaging system of claim 1 wherein: the random microlens array (8) is formed by randomly arranging a plurality of quadrilateral microlenses, pentagonal microlenses and hexagonal microlenses on a round glass substrate, wherein each microlens is an ellipsoid.
3. The random microlens array digital holographic speckle suppression imaging system of claim 1 wherein: the center of the random micro lens array (8) is provided with a through hole, and the through hole is connected with the shaft of the motor (9) and is driven by the motor to rotate.
4. The random microlens array digital holographic speckle suppression imaging system of claim 1 wherein: the random micro lens array (8) is arranged in the optical path of the object light, and is arranged between the objective lens (7) and the convex lens (10); the random micro lens array (8) serves as a diffuser, plays a role of homogenizing light, and can effectively inhibit speckle noise in a digital holographic system.
5. The system for digital holographic speckle reduction imaging of random microlens arrays of claim 1, wherein for the design of the random microlens array, comprising the steps of: creating a reference plane for locating the position of the microlens; randomly generating a group of points on a reference plane to serve as the center of the micro lens; for each point, creating a micro lens at a corresponding position according to preset parameters; the micro lens is an ellipsoid; and finally, generating a round substrate under the micro lens, wherein the center of the round substrate is provided with a through hole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310666314.4A CN116560203A (en) | 2023-06-07 | 2023-06-07 | Digital holographic speckle suppression imaging system based on random microlens array |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310666314.4A CN116560203A (en) | 2023-06-07 | 2023-06-07 | Digital holographic speckle suppression imaging system based on random microlens array |
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| CN116560203A true CN116560203A (en) | 2023-08-08 |
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| CN202310666314.4A Pending CN116560203A (en) | 2023-06-07 | 2023-06-07 | Digital holographic speckle suppression imaging system based on random microlens array |
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- 2023-06-07 CN CN202310666314.4A patent/CN116560203A/en active Pending
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