CN113687510A - Light path folding reflection type large-view-field compound eye imaging optical system and method thereof - Google Patents
Light path folding reflection type large-view-field compound eye imaging optical system and method thereof Download PDFInfo
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Abstract
A light path folding reflection type large-view-field compound eye imaging optical system and a method thereof belong to the technical field of large-view-field optical imaging systems and bionic compound eye imaging detectors. The system is designed into a large-view-field bionic compound eye imaging system of a multi-channel single detector, multi-view sub-eye image surface coplanarity and single-photodetector partition imaging are realized in a light path refraction and light path normalization mode, the detection view field is expanded while the system is designed in a light weight mode, the compound eye system achieves the advantages of low cost, small size, light weight, wide detection field and the like, can be carried on platforms with limited loads, such as small unmanned equipment, low-speed rocket and the like, provides large-view-field visual imaging and detection support for the platforms, can be used independently, and completes machine visual detection tasks, such as large-view-field monitoring, identification, early warning and the like.
Description
Technical Field
The invention belongs to the technical field of large-field-of-view optical imaging systems and bionic compound eye imaging detectors, and particularly relates to a compact optical path folding reflection type large-field-of-view compound eye imaging optical system and an imaging method thereof.
Background
At present, the conventional visual imaging and detecting device adopts a single lens group-single photodetector configuration, namely a traditional single-aperture imaging camera set. Due to the restriction of an optical imaging principle and a mapping relation, the field angle of the single-aperture detector is in an inverse proportional relation with the focal length, so that the detection distance of the imaging system must be sacrificed and the system aperture must be further enlarged to realize the large-field detection capability. However, this configuration has reached the limit of optimization if further miniaturization of the system is desired with an enlarged detection field of view.
In order to break through the imaging limitation of a single-aperture system, researchers develop the research of an artificial bionic compound eye imaging detector according to the imaging principle and the structural characteristics of insect compound eyes. The patent CN211786240U utilizes optical fiber bundles to couple a plurality of sub-glasses groups to a target surface of a photodetector, so as to realize multi-view synchronous imaging, break through the contradiction between high resolution and large imaging field, and realize bionic functional features such as three-dimensional space positioning, moving target fast tracking, super-resolution reconstruction and identification; the open patent CN107718611B combines 3D printing and negative pressure die forming technology to produce the organosilicon flexible curved surface compound eye film, the compound eye preparation process is simple to operate, the processing period is short, the expansibility is strong, and the problems of convenience and low cost of producing bionic compound eye products with different micro-lens curvatures in the prior art are effectively solved; the patent publication CN104165626B discloses that the field angle is enlarged by an optical relay system, and a bionic compound eye imaging target positioning system capable of focusing incident light to a detector array with curved surface distribution for imaging is designed. The patent plays a key role in the development of the bionic compound eye, but still has certain limitations. For example, in the patent CN211786240U, the optical fiber imaging beam is difficult to process and assemble, the light flux mapping is insufficient, and the cost of the adopted large target surface photodetector is high, which results in that the device is difficult to be produced in mass; although the manufacturing cost and the processing difficulty are effectively reduced in the patent publication CN107718611B, the curved flexible compound eye film only supports the processing of a single lens eye on a substrate, the compound eye film with the structure has the advantages of short detection distance and low imaging quality, and cannot be applied to actual imaging and detection environments; the patent CN104165626B has a large field of view and a high resolution, but the utilization rate of the optical space in the detector is low, which results in a large overall size of the system and inconsistent optical paths of the sub-eyes at different positions, which results in large imaging aberration of the sub-eyes at the edge of the field of view, and will have a certain influence on the subsequent imaging and the identification detection. The conventional compound eye detector has certain limitations when facing a real detection environment.
At present, the balance of the compound eye system in wide area detection, low cost, high definition imaging, quick response and light weight of equipment is not realized at home and abroad.
Disclosure of Invention
Aiming at the problems of large volume and mass, high spare part cost, high image data generation amount and the like of a multi-camera array compound eye system in the prior art, the invention provides a light path folding reflection type large-view-field compound eye imaging optical system and a method thereof, designs a multi-channel-single detector large-view-field bionic compound eye imaging system, by means of light path refraction and light path normalization, multi-view sub-eye image surface coplanarity and single photoelectric detector partition imaging are realized, the detection vision field is enlarged while the system lightweight design is met, and the compound eye system achieves the advantages of low cost, small size, light weight, wide detection field and the like, the device can be carried on platforms with limited loads such as small unmanned equipment and low-speed rocket, provides large-view-field visual imaging and detection support for the small unmanned equipment and low-speed rocket, and can be independently used to complete machine visual detection tasks such as large-view-field monitoring, identification and early warning. The specific technical scheme is as follows:
a light path folding reflection type large-view-field compound eye imaging optical system is an N-level imaging structure, wherein N is more than or equal to 1, each level imaging structure is composed of three sub-eye channels and a photoelectric detector, the main optical axes of the three sub-eye channels are perpendicular to each other under adjacent channels and are located on the same plane, and the photoelectric detector specifically comprises a target surface 1 of the photoelectric detector, an edge sub-glasses group 2, a center sub-glasses group 3 and a reversing prism 4; as shown in fig. 13;
two symmetrical reversing prisms 4 are arranged on two sides of the photoelectric detector target surface 1, a center sub-glasses group 3 is arranged in the middle Y-axis direction of the photoelectric detector target surface 1, two symmetrical edge sub-glasses groups 2 are arranged in the X-axis direction of two ends of the outer side of the photoelectric detector target surface 1, and the mirror surfaces of the two edge sub-glasses groups 2 are respectively opposite to the right-angle surfaces of the two reversing prisms 4;
the central sub-glasses group 3 is positioned at the center of the imaging layer, the light path is vertical to the target surface 1 of the photoelectric detector, and the light path is not required to be refracted; the two edge sub-glasses groups 2 are positioned at two ends of an imaging level and need to be subjected to light path refraction and reflection; right-angle surfaces on one sides of the two reversing prisms 4 are coupled with a target surface 1 of the photoelectric detector, and right-angle surfaces on the other sides of the two reversing prisms are used for receiving channel optical signals corresponding to the two edge sub-glasses groups 2; the two reversing prisms 4 realize the reflection and folding of the light paths of the two edge sub-glasses groups 2; the central sub-glasses group 3 and the two edge sub-glasses groups 2 are identical in optical structure, and the equivalent optical lengths are kept consistent; the central sub-glasses group 3 and the two edge sub-glasses groups 2 perform trisection subarea imaging on the target surface 1 of the photoelectric detector and synchronously map corresponding imaging subareas; after light path refraction and reflection, three sub-eye image planes of each level of imaging structure are superposed with the target surface 1 of the photoelectric detector;
the central lines of the two symmetrical edge sub-glasses groups 2 form a transverse main optical axis 5, the central line of the central sub-glasses group 3 forms a longitudinal main optical axis 6, the intersection of the transverse main optical axis 5 and the longitudinal main optical axis 6 is a main optical axis intersection point O7, and an adjacent sub-eye main optical axis included angle theta 10 is formed; a visual field blind point B8 is respectively formed at the intersection of the visual field boundary line of the center sub-glasses group 3 and the visual field boundary lines of the two edge sub-glasses groups 2; the boundary line of the field of view of the central sub-glasses group 3 and the longitudinal main optical axis 6 form a sub-eye half-field of view omega 9; as shown in fig. 1;
a method for manufacturing a light path folding reflection type large-view-field compound eye imaging optical system comprises the following steps:
step 1: determining a use environment and detection requirements, and measuring or calculating the whole field angle, the quality, the volume, the detection distance, the detection target resolution and the imaging resolution of the optical path folding reflection type large-field compound eye imaging optical system;
step 2: developing the design of a light path folding reflection type large-view-field compound eye imaging optical system, and solving optical design parameters and constraint conditions of a single-channel sub-eye;
the size of the prism and the size of the target surface of the photoelectric detector satisfy the following relation:
wherein X is the target surface width of the photoelectric detector, Y is the target surface height of the photoelectric detector, H is the height of the reversing prism, and D is the right-angle side length of the reversing prism;
the optical structures of the central sub-glasses group 3 and the edge sub-glasses group 2 have the following constraints:
wherein l is the working distance of the sub-eye system, f is the effective focal length, xi is the distance between the reversing prism and the target surface of the photoelectric detector, and omega is the half-field angle of the sub-eye;
the included angle theta between the full field angle 2 omega of the sub-eye and the main optical axis of the adjacent sub-eye should satisfy the following condition:
θ＜2ω≤2θ (3)
the main optical axes of adjacent sub-eyes in the folding reflection type compound eye are mutually vertical, namely theta is equal to 90 degrees; controlling the angle to be 45 degrees < omega ≤ 70 degrees;
with a pixel size p of 3.2 μm × 3.2 μm, the cutoff frequency is:
and step 3: simulating a central sub-eye optical system by utilizing Zemax software and a Zebase optical model database, and adjusting the curvature of a curved surface, glass materials, the caliber of a lens group and the interval of lenses in the lens group by local optimization and hammer optimization; meanwhile, a sub-eye optical system point sequence diagram, an MTF diagram and a field curvature/distortion diagram are monitored, and the fact that aberration is in a descending trend in the sub-eye optimization process is guaranteed until design constraints and imaging requirements are met;
and 4, step 4: adjusting the length of the rear working distance of the built central sub-eye optical system, and enabling the rear working distance of the sub-eye to have sufficient space to accommodate the reversing prism for light path offset imaging according to a prism expansion calculation formula; the process is completed by inserting a reflecting prism surface in a Zemax optical model of the central sub-eye, and the imaging quality also needs to be monitored in the process so as to avoid overlarge aberration; after the aberration and the optical size reach within the constraint condition through adjustment, the establishment of the edge sub-eye model is completed;
establishing a compound eye array space coordinate system formed by main optical axes of the central sub-eye and the edge sub-eye, wherein an original point is a main optical axis intersection point O; the array distance between the center of the center sub-eye equivalent model and the point O is lcThe array distance between the center of the edge sub-eye equivalent model and the incident plane of the prism is lb(ii) a For the layout relation of one side of the longitudinal main optical axis, the array distance d between the center of the edge sub-eye equivalent model and the point ObComprises the following steps:
the farthest blind point B exists in the blind area of the refractive compound eye vision field and is positioned at the intersection point of the vision field edges of the adjacent channels; the position (x) of the farthest blind spot B in the compound eye array space coordinate systemB，yB) Expressed as:
after arrangement, the farthest blind spot B position of the compact folding reflection type bionic compound eye is as follows:
and 5: according to the calculation result of the step 4 and the array relation of each sub-eye part, designing each channel array mode and the joint imaging model of the folded reverse compound eye by using the optical model of the central sub-eye and the edge sub-eye which are completely designed, after determining each sub-eye array mode and the layout, establishing an optical structure model of the compact folded reflection type large-view-field compound eye imaging system based on the space coordinates and the relative position information among the components, carrying out ray tracing simulation on the compact folded reflection type large-view-field compound eye imaging system, and comprehensively evaluating the indexes of the whole structure parameters and the optical imaging performance of the folded reverse compound eye;
step 6: and generating a CAD processing drawing according to the established sub-eye Zemax optical model, processing the lens group, and assembling after the processing is finished.
Compared with the prior art, the optical path folding reflection type large-view-field compound eye imaging optical system and the method thereof have the advantages that:
the invention adopts a configuration that a plurality of sub-eyes correspond to a single photoelectric detector for imaging, and utilizes a folding reflection and common image plane imaging technology of a light path to realize large-field imaging and detection in a compact space, thereby achieving the effect of expanding the field range.
The three-channel optical lens group array with the optical axes forming 90 degrees with each other is used as a single imaging level of the compound eye, level expansion can be carried out according to detection requirements, and the compound eye three-channel optical lens group array is flexible to apply and suitable for various scenes and use requirements. For the requirements of multi-dimensional imaging and detection, the imaging levels of the folding reflective compound eye can be expanded to construct a multi-level imaging structure.
Thirdly, the imaging light path of the optical subsystem is deflected by the reversing prism, so that the bionic compound eye is compactly designed, and the bionic compound eye has the advantage of small occupied space.
And fourthly, the invention extends the rear working distance of the central sub-eye through image plane normalization and prism expansion calculation, so that the optical path of the multi-angle sub-eye is equivalent, and the coplanar subarea imaging of a multi-channel single detector is realized, thereby improving the imaging precision which can be improved by more than 30 percent compared with the prior art.
And fifthly, in order to facilitate installation of internal components of the compound eye and resist vibration and overload, the folding reflection type compound eye realizes light path reflection and folding of the edge sub-eye by using the reversing prism.
In summary, the large-view-field bionic compound eye imaging system of the multi-channel single detector is designed, multi-view sub-eye image surface coplanarity and single-photodetector partition imaging are achieved through a light path reflection and light path normalization mode, the detection view field is expanded while the system lightweight design is met, the compound eye system achieves the advantages of low cost, small size, light weight, wide detection field and the like, can be carried on platforms with limited loads, such as small unmanned equipment, low-speed rocket and the like, and provides large-view-field visual imaging and detection support for the platforms, and can be used independently to complete machine visual detection tasks, such as large-view-field monitoring, identification, early warning and the like.
Drawings
Fig. 1 is an imaging schematic diagram of an optical path folding reflection type large-field compound eye imaging optical system of the present invention, wherein: the method comprises the following steps of 1-a target surface of a photoelectric detector, 2-an edge sub-glasses group, 3-a center sub-glasses group, 4-a reversing prism, 5-a transverse main optical axis, 6-a longitudinal main optical axis, 7-a main optical axis intersection point O, 8-a visual field blind point B, 9-a sub-eye half visual field omega, and 10-an adjacent sub-eye main optical axis included angle theta.
FIG. 2 is a sectional view of the target surface of the photodetector according to example 1, wherein: 1-central sub-eye imaging area, 2-edge sub-eye imaging area, 3-view overlap imaging area, 4-photodetector target surface height Y, 5-photodetector target surface width X.
Fig. 3 is an optical structure diagram of a central sub-eye of an optical path folding reflective large-field-of-view compound eye imaging optical system according to embodiment 1.
Fig. 4 is an optical structure diagram of an edge sub-eye of an optical path folding reflective large-field-of-view compound eye imaging optical system according to embodiment 1.
Fig. 5 is a graph of MTF test results of a central sub-eye of the optical path folding reflective large-field compound eye imaging optical system according to embodiment 1.
Fig. 6 is a graph of MTF test results of edge sub-eyes of the optical path folding reflective large-field compound eye imaging optical system according to embodiment 1.
Fig. 7 is a central sub-eye imaging point array diagram of the optical path folding reflection type large-field-of-view compound eye imaging optical system in embodiment 1.
Fig. 8 is a diagram of an edge sub-eye imaging spot array of the optical path folding reflective large-field-of-view compound eye imaging optical system according to embodiment 1.
FIG. 9 is a diagram of an embodiment 1 of an optical path folding reflective large field of view compound eye imagingA same-level central sub-eye and edge sub-eye layout diagram of an optical system, wherein: 1-main optical axis intersection point O, 2-half photoelectric detector target surface width 0.5X, 3-array distance l from center of edge sub-eye equivalent model to prism incident surfacebAnd 4-the array distance between the center of the center sub-eye equivalent model and the point O is lcAnd the distance xi between the 5-reversing prism and the target surface of the photoelectric detector is 6, the included angle theta of the main optical axis of the adjacent sub-eye is 7, the half visual field omega of the sub-eye is 8, and the blind point B of the visual field is formed.
Fig. 10 is an optical structural diagram of an optical path folding reflective large-field-of-view compound eye imaging optical system according to embodiment 1.
Fig. 11 is an optical tracking model diagram of an optical path folding reflective large-field-of-view compound eye imaging optical system according to embodiment 1.
Fig. 12 is a schematic diagram of a prototype packaging effect of an optical path folding reflective large-field-of-view compound eye imaging optical system in embodiment 1.
Fig. 13 is a schematic diagram of a single-layer imaging structure of an optical path folding reflective large-field compound eye imaging optical system of the present invention, wherein: 1-target surface of photoelectric detector, 2-edge sub-glasses group, 3-center sub-glasses group and 4-reversing prism.
Detailed Description
The invention will be further described with reference to specific embodiments and figures 1 to 13, but the invention is not limited to these embodiments.
Example 1
A light path folding reflection type large-view-field compound eye imaging optical system is an N-level imaging structure, wherein N is more than or equal to 1, each level imaging structure is composed of three sub-eye channels and a photoelectric detector, the main optical axes of the three sub-eye channels are perpendicular to each other under adjacent channels and are located on the same plane, and the photoelectric detector specifically comprises a target surface 1 of the photoelectric detector, an edge sub-glasses group 2, a center sub-glasses group 3 and a reversing prism 4; as shown in fig. 13;
two symmetrical reversing prisms 4 are arranged on two sides of the photoelectric detector target surface 1, a center sub-glasses group 3 is arranged in the middle Y-axis direction of the photoelectric detector target surface 1, two symmetrical edge sub-glasses groups 2 are arranged in the X-axis direction of two ends of the outer side of the photoelectric detector target surface 1, and the mirror surfaces of the edge sub-glasses groups 2 are respectively opposite to the right-angle surfaces of the reversing prisms 4.
The central sub-glasses group 3 is positioned at the center of the imaging layer, the light path is vertical to the target surface 1 of the photoelectric detector, and the light path is not required to be refracted; the two edge sub-glasses groups 2 are positioned at two ends of an imaging level and need to be subjected to light path refraction and reflection; right-angle surfaces on one sides of the two reversing prisms 4 are coupled with a target surface 1 of the photoelectric detector, and right-angle surfaces on the other sides of the two reversing prisms are used for receiving channel optical signals corresponding to the two edge sub-glasses groups 2; the two reversing prisms 4 realize the reflection and folding of the light paths of the two edge sub-glasses groups 2; the central sub-glasses group 3 and the two edge sub-glasses groups 2 are identical in optical structure, and the equivalent optical lengths are kept consistent; the central sub-glasses group 3 and the two edge sub-glasses groups 2 perform trisection subarea imaging on the target surface 1 of the photoelectric detector and synchronously map corresponding imaging subareas; after light path refraction and reflection, three sub-eye image planes of each level of imaging structure are superposed with the target surface 1 of the photoelectric detector;
the central lines of the two symmetrical edge sub-glasses groups 2 form a transverse main optical axis 5, the central line of the central sub-glasses group 3 forms a longitudinal main optical axis 6, the intersection of the transverse main optical axis 5 and the longitudinal main optical axis 6 is a main optical axis intersection point O7, and an adjacent sub-eye main optical axis included angle theta 10 is formed; a visual field blind point B8 is respectively formed at the intersection of the visual field boundary line of the center sub-glasses group 3 and the visual field boundary lines of the two edge sub-glasses groups 2; the boundary line of the field of view of the central sub-glasses group 3 and the longitudinal main optical axis 6 form a sub-eye half-field of view omega 9; as shown in fig. 1.
A method for manufacturing a light path folding reflection type large-view-field compound eye imaging optical system comprises the following steps:
the compact folding reflection type bionic compound eye (hereinafter referred to as a folding type compound eye) mainly aims at tasks such as imaging detection, target recognition, visual flight control and the like under a load-limited platform such as small unmanned equipment and the like. Because there is a certain correlation between each optical device parameter of the refractive compound eye and the optical path structure, the imaging principle of the refractive compound eye is the same as the design scheme, and the calculated detection capability and performance parameters have differences. In order to be capable of accurately representing the optical performance parameters of the catadioptric compound eye, clearly showing the design process of each functional component and clearly feeding back the catadioptric compound eye imaging quality and the detection performance, the scheme takes a proposed small unmanned aerial vehicle as a carrier platform and takes vehicle and personnel targets as imaging and detection objects. For the detection environment, the conventional detection distance range is 5 m-75 m, the identification distance range is 10 m-30 m, the allowable load limit of the visual detection platform is 1kg, and the maximum allowable volume of the detector and the processing module thereof is 100mm multiplied by 220mm, so the designed folding reflection type compound eye imaging detection system needs to have the characteristics of light weight, low power consumption, high detection efficiency and the like, and needs to be combined with a facing use environment to obtain the optimal balance between the detection visual field and the detection distance.
In order to meet the requirements, a folding reflection type imaging structure shown in fig. 13 and fig. 1 in the attached drawings is adopted to realize large-field detection and common image surface imaging of the bionic compound eye. The same imaging level of the folding reflection type compound eye is composed of three sub-eye channels and a photoelectric detector, wherein the main optical axes of the three sub-eye channels are perpendicular to each other under adjacent channels and are located on the same plane. The center sub-eye is positioned in the center of the hierarchy, the light path of the center sub-eye is vertical to the target surface of the photoelectric detector, and the center sub-eye does not need to be refracted; the left and right edge sub-eyes are positioned at the two ends of the hierarchy and need to perform light path reflection. Each sub-eye system is identical in optical structure, and the equivalent optical length is kept consistent. After the light path is refracted, the three sub-eye image planes at the same level are superposed with the target surface of the photoelectric detector. In consideration of easy installation, vibration resistance and overload capacity of internal components of the compound eye, the folding reflection type compound eye realizes light path reflection and folding of the edge sub-eye by using the reversing prism. One end of the reversing prism is coupled with the target surface of the photoelectric detector, and the other end of the reversing prism is used for receiving optical signals of the corresponding sub-eye channels. During imaging, the same-level sub-eye divides the target surface of the photoelectric detector into three equal divisions and synchronously maps the corresponding imaging divisions. For the requirements of multi-dimensional imaging and detection, the imaging levels of the folding reflective compound eye can be expanded to construct a multi-level imaging structure. Because each layer of interstage optical structure is the same as the imaging principle, and the single-layer interstage structure can meet the use environment requirement of the scheme, only the single-layer compact folding reflection type bionic compound eye imaging system is researched.
The central sub-eye and the edge sub-eye in the same level can perform subarea imaging on the same photoelectric detector target surface, and at the moment, when the edge sub-eye performs light path reflection by using the reversing prism, the image surface of the edge sub-eye after being reflected by the prism is required to be coplanar with the image surface of the central sub-eye and coincide with the corresponding area of the photoelectric detector target surface. In order to avoid optical path interference generated during synchronous mapping of multiple sub-eyes at the same level, the target surface of the photoelectric detector needs to be divided into regions according to the positions of the different sub-eyes and detection regions, so that the corresponding sub-eyes can only image in the regions. In order to maximize the utilization rate of the target surface of the single photodetector, the target surface partition mode of the photodetector corresponding to each sub-eye at the same level is shown in fig. 2 in the attached drawing.
In order to keep the image surface of the marginal sub-eye after the light path is deflected by the reversing prism complete and not lose imaging information of a marginal field of view, the size of the prism and the size of a target surface of the photoelectric detector meet the following relation:
wherein X, Y is the width and height of the target surface of the photoelectric detector, H, D is the height and the length of the right angle side of the reversing prism. Because the center sub-eye is consistent with the left and right edge sub-eyes in the optical structure, in order to enable the image surfaces of the center sub-eye and the left and right edge sub-eyes to coincide, the rear working distance of the center sub-eye needs to have enough space so that the edge sub-eye with the same structure can contain the reversing prism to perform light path reflection and map the image onto the target surface of the photoelectric detector through the prism, and then the optical structure of the sub-eye has the following constraints:
wherein l is the working distance of the sub-eye system, f is the effective focal length, xi is the distance between the reversing prism and the target surface of the photoelectric detector, and omega is the half-field angle of the sub-eye. In order to prevent compound eyes from generating blind visual angle zones, a certain visual field overlap is required between adjacent sub-eyes. Meanwhile, in order to ensure the improvement of the overall optical performance of the system, the view overlapping area cannot be too large, and the included angle θ between the full field angle 2 ω of the sub-eye and the main optical axis of the adjacent sub-eye should satisfy the following conditions:
θ＜2ω≤2θ (3)
the main optical axes of adjacent sub-eyes in the folding reflection type compound eye are perpendicular to each other, namely theta is equal to 90 degrees. Under the influence of the size and the shape of the target surface of the photoelectric detector, the imaging information of each sub-eye cannot be completely mapped on the corresponding subarea of the photoelectric detector, namely the optical field angle of the sub-eye is smaller than the actual imaging detection field angle. In order to ensure that splicing repeated image information still exists after adjacent sub-eyes are imaged, when the sub-eye system is optically designed, the optical angle of view constraint value is larger than the detection angle of view, and enough field of view reservation is made for splicing imaging overlapping information, so that 45 degrees < omega > is controlled to be less than or equal to 70 degrees in the design process of the scheme.
By combining the requirements and carrying capacity of the small unmanned aerial vehicle and the unmanned vehicle in machine vision application environments of imaging, detection, identification and the like, the conventional detection target and the object space projection size of the bionic compound eye detection system are respectively a vehicle (4.5m multiplied by 1.5m) and a human (0.5m multiplied by 1.7m), the maximum detection distance is no less than 30m, the maximum optical aperture of the sub-eye system is no less than 30mm, and the single-channel optical length is no less than 50 mm.
For different detection environments, the sub-eye optical structure of the catadioptric compound eye and the imaging performance of the photoelectric detector need to be adjusted by combining different task requirements. In the scheme, the pixel size p is 3.2 microns multiplied by 3.2 microns, and the cutoff frequency is as follows:
the object space spatial resolution of the folded compound eye at the position of 30m is taken to be 0.2m, and the optical design parameters and the constraint conditions of the single-channel sub-eye shown in the table 1 can be solved according to the design principle of the optical system and the imaging geometrical relationship of the folded compound eye by combining the design requirements.
TABLE 1 Single channel sub-eye optical design parameters and constraints
Using table 1 as an initial condition, the center sub-eye and the edge sub-eye were optically designed using ZEMAX software. In the method, a wide-angle optical imaging system in a Zebase optical model library is used as a basic configuration, and after reconstruction and optimization, the optical structure and imaging quality simulation results of the central sub-eye and the edge sub-eye of the compact folding reflection type compound eye are shown in figures 3 to 8 in the attached drawings.
In fig. 3 and 4, the optical total lengths of the central sub-eye and the edge sub-eye single channel are 26.54mm and 29.66mm respectively, and the maximum aperture of the sub-eye system is 6.86mm, so that the design size requirement of the compact compound eye is met; in fig. 5 and 6, the minimum MTF value of the full field at 156lp/mm of the center sub-eye and the edge sub-eye is greater than 0.3, and the curves are smooth, so that the image quality is good; in fig. 7 and 8, the radius of the airy disk is 3.00 μm, and the RMS radius of each channel sub-eye is smaller than the radius of the airy disk within the range of 0- ω -45 °, so as to meet the requirement of large-field-of-view clear imaging of the catadioptric compound eye. Partial sub-eye channels have RMS radii slightly larger than airy disc radius in the field of view range 45 ° < ω <70 °, which causes some imaging aberrations. However, if the numerical value is beyond the allowable distortion range, the image correction algorithm can reduce the lens group edge aberration, and the imaging information within the field of view range is only used as a contrast reference for the subsequent splicing algorithm. Meanwhile, the overlapping vision field of the adjacent sub-eyes is greatly reserved, and after the area with large aberration is corrected, cut and filtered, the single-channel sub-eyes can still be ensured to have an effective imaging angle of view not less than 90 degrees, the requirement of large-field detection and global imaging splicing can be met, and therefore the detection efficiency of the bionic compound eye system is not influenced. The magnification of the sub-eye system is calculated as-0.00023 using the operand PMAG, and the imaging distance on the target surface of the photodetector is 46 μm for two targets located at 30m and 0.2m apart. Combining the rayleigh criterion with the size of the scattered spot in each field in fig. 7 and 8, the object resolution of the sub-glasses group reaches 0.2 m.
In summary, the designed central sub-eye and the edge sub-eye after optical path refraction and reflection have good imaging quality, and on the basis of realizing optical path refraction and partitioned imaging of the same photoelectric detector, the optical system is used as a sub-eye single-channel lens group structure of a compact folding reflective compound eye to ensure that adjacent sub-eye channels have certain view field overlapping.
After the optical structure design of the center sub-eye and the edge sub-eye is completed, the array position of each sub-eye at the same level is determined, the integral compact and large-field design of the compound eye system is realized, and the vision field blind area of the compound eye system is calibrated. In the array process, the optical imaging parts of the central sub-eye and the edge sub-eye are relatively independent, and an optical equivalent model is established for each sub-eye channel to obtain the layout relation of the central sub-eye and the edge sub-eye in the same level as shown in fig. 9 in the attached drawing.
The central sub-eye is placed at the front end of the photoelectric detector, and the main optical axis is superposed with the normal of the center of the target surface of the photoelectric detector; the left and right marginal sub-eyes are respectively placed on two sides of the photoelectric detector, and the main optical axis is superposed with the central normal of the incident surface of the corresponding reversing prism. And establishing a compound eye array space coordinate system formed by the main optical axes of the central sub-eye and the edge sub-eye, wherein the origin point of the compound eye array space coordinate system is the intersection point O of the main optical axes of all channels. The array distance between the center of the center sub-eye equivalent model and the point O is lcThe array distance between the center of the edge sub-eye equivalent model and the incident plane of the prism is lb. For the layout relation of one side of the longitudinal main optical axis, the array distance d between the center of the edge sub-eye equivalent model and the point ObComprises the following steps:
the most distant blind point B exists in the blind zone of the refractive compound eye vision field, and the blind point is positioned at the intersection point of the vision field edges of the adjacent channels. According to the geometrical relationship shown in fig. 9, the farthest blind spot B is located in the compound eye array space coordinate system (x)B，yB) Can be expressed as:
after arrangement, the farthest blind spot B position of the compact folding reflection type bionic compound eye is as follows:
from the above formula, the blind zone calibration position equation already contains the positioning parameters of all optical devices in the compound eye system design process. The scheme combines the optical design constraint conditions and the carrying capacity of small unmanned equipment, calculates the array position of each sub-eye system in the compact folding reflective bionic compound eye under the single-layer level, and simulates and optimizes the positioned three sub-eye combined imaging optical model by utilizing Zemax software to obtain the optical imaging principle model of the compact folding reflective compound eye under the single-layer level, which is shown in figure 10 in the attached drawing.
In fig. 10, the optical dimensions of the catadioptric compound eye are 29.78mm × 19.74mm × 6.82mm, the overall optical field of view of the system is 320 ° × 140 °, and the blind spot B coordinates are (26.08mm,22.65 mm). Firstly, joint imaging simulation is carried out on each sub-eye channel, and then the compact folding reflection type large-view-field compound eye imaging optical system imaging tracking model is shown in figure 11 in the attached drawing. According to the imaging model combining imaging analysis of each channel and multiple channels, the catadioptric compound eye designed by the scheme realizes multi-angle large-field-of-view clear imaging, improves the utilization rate of the internal space of the compound eye and reduces the carrying quantity of photoelectric detectors through the mode of light path turning back and image surface normalization, and realizes the compact design of the bionic compound eye imaging system.
According to imaging requirements of imaging field angles, detection distances, target identification sizes, object space resolution and the like in different detection tasks, and simultaneously in combination with constraint conditions of the carrying platform on the mass, the volume, the power consumption and the like of the compound eye system, the sub-eye optical structure and the channel space array mode of the catadioptric compound eye system in the environment can be determined. According to the principle, the compact folding reflection type large-field compound eye imaging optical system after being packaged is shown in a prototype in figure 12 in the attached drawing. So far, the present embodiment has completed the preparation and design description of the compact folding reflective large-field compound eye imaging optical system.
Claims (6)
1. A light path folding reflection type large-view-field compound eye imaging optical system is an N-level imaging structure, wherein N is more than or equal to 1, each level imaging structure is composed of three sub-eye channels and a photoelectric detector, the main optical axes of the three sub-eye channels are perpendicular to each other under adjacent channels and are positioned on the same plane, and the system is characterized by specifically comprising a target surface (1) of the photoelectric detector, an edge sub-glasses group (2), a center sub-glasses group (3) and a reversing prism (4);
two symmetrical reversing prisms (4) are arranged on two sides of the target surface (1) of the photoelectric detector, a central sub-glasses group (3) is arranged in the middle Y-axis direction of the target surface (1) of the photoelectric detector, two symmetrical edge sub-glasses groups (2) are arranged in the X-axis direction of two ends of the outer side of the target surface (1) of the photoelectric detector, and the mirror surfaces of the two edge sub-glasses groups (2) are respectively opposite to the right-angle surfaces of the two reversing prisms (4);
the central sub-glasses group (3) is positioned in the center of the imaging layer, the light path is vertical to the target surface (1) of the photoelectric detector, and the light path is not required to be refracted; the two edge sub-glasses groups (2) are positioned at two ends of an imaging level and need to be subjected to light path refraction and reflection; right-angle surfaces on one sides of the two reversing prisms (4) are coupled with a target surface (1) of the photoelectric detector, and right-angle surfaces on the other sides of the two reversing prisms are used for receiving channel optical signals corresponding to the two edge sub-glasses groups (2); the two reversing prisms (4) realize the reflection and folding of the light paths of the two edge sub-glasses groups (2); the central sub-glasses group (3) and the two edge sub-glasses groups (2) are identical in optical structure, and the equivalent optical paths are kept consistent; the central sub-glasses group (3) and the two edge sub-glasses groups (2) perform trisection subarea imaging on the target surface (1) of the photoelectric detector and synchronously map corresponding imaging subareas; after the refraction and reflection of the light path, three sub-eye image planes of each level of imaging structure are superposed with the target surface (1) of the photoelectric detector.
2. The optical path folding reflection type large-field compound eye imaging optical system according to claim 1, wherein the central lines of two symmetrical edge sub-glasses groups (2) form a transverse main optical axis (5), the central line of the central sub-glasses group (3) forms a longitudinal main optical axis (6), the intersection of the transverse main optical axis (5) and the longitudinal main optical axis (6) is a main optical axis intersection point O (7), and an included angle θ (10) between the main optical axes of adjacent sub-eyes is formed; a visual field blind point B (8) is respectively formed at the intersection of the visual field boundary line of the central sub-glasses group (3) and the visual field boundary lines of the two edge sub-glasses groups (2); the boundary line of the field of view of the central sub-glasses group (3) and the longitudinal main optical axis (6) form a sub-eye half-field of view omega (9).
3. The method for manufacturing the optical path folding reflection type large-field compound eye imaging optical system according to claim 1, characterized by comprising the following steps:
step 1: determining a use environment and detection requirements, and measuring or calculating the whole field angle, the quality, the volume, the detection distance, the detection target resolution and the imaging resolution of the optical path folding reflection type large-field compound eye imaging optical system;
step 2: developing the design of a light path folding reflection type large-view-field compound eye imaging optical system, and solving optical design parameters and constraint conditions of a single-channel sub-eye;
and step 3: simulating a central sub-eye optical system by utilizing Zemax software and a Zebase optical model database, and adjusting the curvature of a curved surface, glass materials, the caliber of a lens group and the interval of lenses in the lens group by local optimization and hammer optimization; meanwhile, a sub-eye optical system point sequence diagram, an MTF diagram and a field curvature/distortion diagram are monitored, and the fact that aberration is in a descending trend in the sub-eye optimization process is guaranteed until design constraints and imaging requirements are met;
and 4, step 4: adjusting the length of the rear working distance of the built central sub-eye optical system, and enabling the rear working distance of the sub-eye to have sufficient space to accommodate the reversing prism for light path offset imaging according to a prism expansion calculation formula; the process is completed by inserting a reflecting prism surface in a Zemax optical model of the central sub-eye, and the imaging quality also needs to be monitored in the process so as to avoid overlarge aberration; after the aberration and the optical size reach within the constraint condition through adjustment, the establishment of the edge sub-eye model is completed;
and 5: according to the calculation result of the step 4 and the array relation of each sub-eye part, designing each channel array mode and the joint imaging model of the folded reverse compound eye by using the optical model of the central sub-eye and the edge sub-eye which are completely designed, after determining each sub-eye array mode and the layout, establishing an optical structure model of the compact folded reflection type large-view-field compound eye imaging system based on the space coordinates and the relative position information among the components, carrying out ray tracing simulation on the compact folded reflection type large-view-field compound eye imaging system, and comprehensively evaluating the indexes of the whole structure parameters and the optical imaging performance of the folded reverse compound eye;
step 6: and generating a CAD processing drawing according to the established sub-eye Zemax optical model, processing the lens group, and assembling after the processing is finished.
4. The method for manufacturing the optical path folding reflective large-field-of-view compound eye imaging optical system according to claim 3, wherein in the step 2:
the size of the prism and the size of the target surface of the photoelectric detector satisfy the following relation:
wherein X is the target surface width of the photoelectric detector, Y is the target surface height of the photoelectric detector, H is the height of the reversing prism, and D is the right-angle side length of the reversing prism;
the optical structures of the central sub-glasses group 3 and the edge sub-glasses group 2 have the following constraints:
wherein l is the working distance of the sub-eye system, f is the effective focal length, xi is the distance between the reversing prism and the target surface of the photoelectric detector, and omega is the half-field angle of the sub-eye;
the included angle theta between the full field angle 2 omega of the sub-eye and the main optical axis of the adjacent sub-eye should satisfy the following condition:
θ＜2ω≤2θ (3)
the main optical axes of adjacent sub-eyes in the folding reflection type compound eye are mutually vertical, namely theta is equal to 90 degrees; controlling the angle to be 45 degrees < omega <70 degrees.
5. The method for manufacturing the optical path folding reflective large-field-of-view compound eye imaging optical system according to claim 3, wherein in the step 2:
with a pixel size p of 3.2 μm × 3.2 μm, the cutoff frequency N is:
6. the method for manufacturing the optical path folding reflective large-field-of-view compound eye imaging optical system according to claim 3, wherein in the step 4:
establishing a compound eye array space coordinate system formed by main optical axes of the central sub-eye and the edge sub-eye, wherein an original point is a main optical axis intersection point O; the array distance between the center of the center sub-eye equivalent model and the point O is lcThe array distance between the center of the edge sub-eye equivalent model and the incident plane of the prism is lb(ii) a For the layout relation of one side of the longitudinal main optical axis, the array distance d between the center of the edge sub-eye equivalent model and the point ObComprises the following steps:
the farthest blind point B exists in the blind area of the refractive compound eye vision field and is positioned at the intersection point of the vision field edges of the adjacent channels; the position (x) of the farthest blind spot B in the compound eye array space coordinate systemB，yB) Expressed as:
after arrangement, the farthest blind spot B position of the compact folding reflection type bionic compound eye is as follows:
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115451820A (en) * | 2022-10-21 | 2022-12-09 | 哈尔滨师范大学 | Three-channel polarization information acquisition system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010062257A1 (en) * | 2008-11-28 | 2010-06-03 | Stelop Pte. Ltd. | An apparatus for imaging |
| CN205545523U (en) * | 2016-01-20 | 2016-08-31 | 福建福特科光电股份有限公司 | Big target surface low light level whole day ball camera system |
| CN107846534A (en) * | 2017-09-18 | 2018-03-27 | 努比亚技术有限公司 | A kind of camera and photographic method |
| CN207225252U (en) * | 2017-09-04 | 2018-04-13 | 信利光电股份有限公司 | A kind of camera module and vehicle viewing system |
| CN108415216A (en) * | 2018-03-27 | 2018-08-17 | 捷西迪（广州）光学科技有限公司 | A kind of prism total reflection twin-lens is total to chip module |
| CN211531173U (en) * | 2020-03-30 | 2020-09-18 | 华中科技大学 | Optical imaging lens suitable for panoramic photography |
-
2021
- 2021-07-19 CN CN202110811754.5A patent/CN113687510A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010062257A1 (en) * | 2008-11-28 | 2010-06-03 | Stelop Pte. Ltd. | An apparatus for imaging |
| CN205545523U (en) * | 2016-01-20 | 2016-08-31 | 福建福特科光电股份有限公司 | Big target surface low light level whole day ball camera system |
| CN207225252U (en) * | 2017-09-04 | 2018-04-13 | 信利光电股份有限公司 | A kind of camera module and vehicle viewing system |
| CN107846534A (en) * | 2017-09-18 | 2018-03-27 | 努比亚技术有限公司 | A kind of camera and photographic method |
| CN108415216A (en) * | 2018-03-27 | 2018-08-17 | 捷西迪（广州）光学科技有限公司 | A kind of prism total reflection twin-lens is total to chip module |
| CN211531173U (en) * | 2020-03-30 | 2020-09-18 | 华中科技大学 | Optical imaging lens suitable for panoramic photography |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115451820A (en) * | 2022-10-21 | 2022-12-09 | 哈尔滨师范大学 | Three-channel polarization information acquisition system |
| CN115451820B (en) * | 2022-10-21 | 2024-05-14 | 哈尔滨师范大学 | Three-channel polarization information acquisition system |
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