A Novel System for Moving Object Detection Using Bionic Compound Eyes

Conventional moving target detection focuses on algorithms to improve detection efficiency. These algorithms pay less attention to the image acquisition means, and usually solve specific problems. This often results in poor flexibility and reus- ability. Insect compound eyes offer unique advantages for moving target detection and these advantages have attracted the attention of many researchers in recent years. In this paper we proposed a new system for moving target detection. We used the detection mechanism of insect compound eyes for the simulation of the characteristics of structure, control, and function. We discussed the design scheme of the system, the development of the bionic control circuit, and introduced the proposed mathe- matical model of bionic cqmpound eyes for data acquisition and object detection. After this the integrated system was described and discussed. Our paper presents a novel approach for moving target detection. This approach effectively tackles some of the well-known problems in the field of view, resolution, and real-time processing problems in moving target detection.

Fabrication of Waterproof Artificial Compound Eyes with Variable Field of View Based on the Bioinspiration from Natural Hierarchical Micro–Nanostructures

Planar and curved microlens arrays(MLAs)are the key components of miniaturized microoptical systems.In order to meet the requirements for advanced and multipurpose applications in microoptical field,a simple manufacturing method is urgently required for fabricating MLAs with unique properties,such as waterproofness and variable field-of-view(FOV)imaging.Such properties are beneficial for the production of advanced artificial compound eyes for the significant applications in complex microcavity environments with high humidity,for instance,miniature medical endoscopy.However,the simple and effective fabrication of advanced artificial compound eyes still presents significant challenges.In this paper,bioinspired by the natural superhydrophobic surface of lotus leaf,we propose a novel method for the fabrication of waterproof artificial compound eyes.Electrohydrodynamic jet printing was used to fabricate hierarchical MLAs and nanolens arrays(NLAs)on polydimethylsiloxane film.The flexible film of MLAs hybridized with NLAs exhibited excellent superhydrophobic property with a water contact angle of 158°.The MLAs film was deformed using a microfluidics chip to create artificial compound eyes with variable FOV,which ranged from 0°to 160°.

Femtosecond laser fabrication of 3D templates for mass production of artificial compound eyes

Compound eyes are unique optical imaging systems that consist of numerous separate light-sensitive units(ommatidia).Attempts have been made to produce artificial compound eyes via advanced 3 D nanotechnologies.Among them,femtosecond laser direct writing(FsLDW)technology has emerged as an effective strategy due to its distinct advantages in 3 D designable and high precision fabrication capability.However,the point-by-point scanning process results in a very low fabrication efficiency,limiting the practical applications of the FsLDW technology.To solve this problem,we propose a high-efficiency method for the mass production of 3 D artificial compound eyes using a photopolymer template fabricated by FsLDW.The resultant 3 D SU-8 compound eye templates could be used to replicate polydimethylsiloxane(PDMS)compound eyes many times(over 50 times)with a highly improved efficiency(nearly 20 times higher than the efficiency of direct fabrication using the point-by-point FsLDW).The PDMS replicas showed good focusing and imaging performances.We anticipate that this method may serve as an enabler for the mass production of 3 D artificial compound eyes and promote their practical applications in the near future.

Theoretical and Experimental Research on Error Analysis and Optimization of Tool Path in Fabricating Aspheric Compound Eyes by Precision Micro Milling

Structure design and fabricating methods of three-dimensional （3D） artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes （ACEs） are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye （ACE） with surface roughness （Ra） below 0.12 p.m is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.

Simple and High-Efficiency Preparation Method of Biometric 3D Artificial Compound Eyes for Wide-Field Imaging

Three-dimensional(3D)artificial compound eyes(ACEs)are helpful for wide field-o-fview imaging and sensing system applications.However,existing batch preparation methods are technically challenging.A bio-inspired,simple,and high-efficiency batch preparation method is proposed,which involves bonding a sticky microlens array(MLA)polydimethylsiloxane(PDMS)film to an elastic PDMS hemisphere under pressure,followed by abrupt pressure removal.Characterizations from a scanning electron microscope and laser scanning confocal microscope show that 3D ACEs prepared using the proposed method have high numbers of uniformly distributed ommatidia with a high-quality finish.Furthermore,optical imaging investigations demonstrate that the proposed preparation method can achieve clear,distortionfree imaging with a wide field-of-view(up to 140.2°).

Ultrastructure of the compound eye of Longitarsus lewisii(Baly,1874)(Coleoptera,Chrysomelidae)

In this study,the morphology and ultrastructure of the compound eye of L.lewisii were investigated using scanning electron microscopy(SEM),transmission electron microscopy(TEM),microcomputed tomography(μCT),and 3D reconstruction.The compound eye of L.lewisii was of the apposition type,with an average of 121.88±7.64 ommatidia in males and 119.00±4.71 ommatidia in females.Each ommatidium was composed of a biconvex cornea,an acone consisting of four cone cells,eight retinular cells along with the rhabdom,two primary pigment cells,and numerous secondary pigment cells.The open type of rhabdom in L.lewisii consists of six peripheral rhabdomeres contributed by the six peripheral retinular cells(R1~R6)and two vertically attached central rhabdomeres contributed by R7 and R8 respectively.The orientation of microvilli suggested a weak sensitivity to polarized light perception.

Compound diffractive telescope system:design,stray light analysis,and optical test

The compound diffractive telescope is a novel space optical system which combines the structure of compound eyes with diffractive optics and so it has a lighter weight, a wider field of view （FOV）, a lower cost as well as looser fabrication tolerance. In this paper, the design of a compound diffractive telescope composed of one primary lens and twenty-one eyepieces is introduced. Then the influence of diffraction orders on the performance of the system is analysed. A modified phase function model of diffractive optics is proposed to analyse the modulation transfer function （MTF） curves for 0° FOV, which provides a more accurate prediction of the performance of the system. In addition, an optimized mechanism is also proposed to suppress stray light. The star image and resolution tests show that the system can achieve diffraction limit imaging within ±2° of FOV and 4-4 mm of eccentricity. Finally, a series of pictures of an object are taken from different channels, and the splicing of pictures from adjacent FOVs is demonstrated. In summary, the designed system has been proved to have great potential applications.

Bionic Mosaic Method of Panoramic Image Based on Compound Eye of Fly

To satisfy the requirements of real-time and high quality mosaics, a bionic compound eye visual system was designed by simulating the visual mechanism of a fly compound eye. Several CCD cameras were used in this system to imitate the small eyes of a compound eye. Based on the optical analysis of this system, a direct panoramic image mosaic algorithm was proposed. Several sub-images were collected by the bionic compound eye visual system, and then the system obtained the overlapping proportions of these sub-images and cut the overlap sections of the neighboring images. Thus, a panoramic image with a large field of view was directly mosaicked, which expanded the field and guaranteed the high resolution. The experimental results show that the time consumed by the direct mosaic algorithm is only 2.2% of that by the traditional image mosaic algorithm while guaranteeing mosaic quality. Furthermore, the proposed method effectively solved the problem of misalignment of the mosaic image and eliminated mosaic cracks as a result of the illumination factor and other factors. This method has better real-time properties compared to other methods.

Study on the relationship between the diameter of the compound eye and the growth of the Antarctickrill

Correlation between the body length and the diameter of the compound eyeof the Antarctic krill Euphausis sulfa was examined. From the samples collected inthe late summer, it shows that there is an apparent exponential relationship betweeneye diameter and the body length. From the laboratory population, it seems that whenthe krill shrink, the diameter of the compound eye does not decrease. It is more reliableto use the eye diameter as krill growth index than they length. The ratio of the theylength to the diameter of the compound eye offers another method for detecting the effect of shrinking in natural populations of krill.

A Novel Artificial Superposition Compound Eye

A new artificial superposition compound eye model is presented based on micro-lens array. In all compound eyes,it has the advantages of small volume,light weight,wide FOV,high sensitivity and much higher energy utilization ratio. Nevertheless,its structure is relatively complicated,especially the GRIN medium in the crystalline cone. Therefore,the modeling,analysis and fabrication for it are burdensome. In the established model,the GRIN is replaced by a curved micro-lens array. Thus,the modeling,analysis and optimization process are simple,and the components of artificial superposition compound eye are easy to be fabricated. The system is modeled by ZEMAX software. With the help of raytracing,its principle is analyzed,and the sensitivity comparison between the superposition compound eye and the apposition compound eye is done. The model's validity is proven.

Holographic laser fabrication of 3D artificial compound μ-eyes

The demand for fast optical image acquisition without movable optical elements(e.g.,for self-driving car technology)can be met using bioinspired 3D compound eyes.3D laser processing strategies enable designable 3D structuring but suffer from low fabrication efficiency,which significantly limits their applications in producing complex 3D optical devices.Herein,we demonstrate a versatile yet simple wet-etching-assisted holographic laser fabrication method for the development of 3D compound eyes.Artificial compoundμ-eyes can be readily fabricated by programming a 3D spot array for the parallel ablation of a curved fused silica surface,followed by controllable etching in a hydrofluoric(HF)acid solution.A 3D-concave-lens array made on a curved surface over an area of 100μm cross-section with each lenslet of 10μm radius was fabricated with high fidelity and excellent imaging/focusing quality.The resultant 3D-concave-lens can serve as a hard template for the mass production of soft compound eyes through soft lithography.Additionally,using a generative adversarial network(GAN)-based deep learning algorithm,image restoration was conducted for each lenslet,which retained a large field of view and significantly improved image quality.This method provides a simple solution to the requirements of compoundμ-eyes required by Industry 4.0.

Mechanics of bioinspired imaging systems

Imaging systems in nature have attracted a lot of research interest due to their superior optical and imaging characteristics, Recent advancements in materials science, mechanics, and stretchable electronics have led to successful development of bioinspired cameras that resemble the structures and functions of biological light-sensing organs. In this review, we discuss some recent progresses in mechanics of bioinspired imaging systems, including tunable hemispherical eyeball camera and artificial compound eye camera. The mechanics models and results reviewed in this article can provide efficient tools for design and optimization of such systems, as well as other related optoelectronic systems that combine rigid elements with soft substrates.

ten-a overexpression causes abnormal pattern in the Drosophila compound eye

Ten-a is one of the two Drosophila proteins that belong to the Ten M protein family. This protein is a type Ⅱ transmembrane protein and is expressed mainly in the embryonic CNS, in the larval eye imaginal disc and in the compound eye of the pupa. Here, we investigate the role of ten-α during development of the compound eye by using the Gal4/ UAS system to induce ten-α overexpression in the developing eye. We found that overexpression of ten-α can perturb eye development during all stages examined. In an early stage, overexpression of ten-α in eye primordial cells caused small and rough eyes and interfered with photoreceptor cell recruitment, resulting in some ommatidia having fewer or extra photoreceptor cells. Conversely, ten-α overexpression daring ommatidial formation caused severe eye defects due to absence of many cellular components. Interestingly, overexpression of ten-α in the late stage developing ommatidial cluster affected the number of pigment cells, caused cone cells proliferation in many ommatidia, and caused some photoreceptor cell defects. These results suggest that ten-α may be a novel gene required for normal eye morphogenesis.

Recent advances in bioinspired vision systems with curved imaging structures

Limited by the planar imaging structure,the commercial camera needs to introduce additional optical elements to compensate for the curved focal plane to match the planar image sensor.This results in a complex and bulky structure.In contrast,biological eyes possess a simple and compact structure due to their curved imaging structure that can directly match with the curved focal plane.Inspired by the structures and functions of biological eyes,curved vision systems not only improve the image quality,but also offer a variety of advanced functions.Here,we review the recent advances in bioinspired vision systems with curved imaging structures.Specifically,we focus on their applications in implementing different functions of biological eyes,as well as the emerging curved neuromorphic imaging systems that incorporate bioinspired optical and neuromorphic processing technologies.In addition,the challenges and opportunities of bioinspired curved imaging systems are also discussed.

Multi-aperture optical imaging systems and their mathematical light field acquisition models

Inspired by the compound eyes of insects,many multi-aperture optical imaging systems have been proposed to improve the imaging quality,e.g.,to yield a high-resolution image or an image with a large field-ofview.Previous research has reviewed existing multi-aperture optical imaging systems,but few papers emphasize the light field acquisition model which is essential to bridge the gap between configuration design and application.In this paper,we review typical multi-aperture optical imaging systems(i.e.,artificial compound eye,light field camera,and camera array),and then summarize general mathematical light field acquisition models for different configurations.These mathematical models provide methods for calculating the key indexes of a specific multiaperture optical imaging system,such as the field-of-view and sub-image overlap ratio.The mathematical tools simplify the quantitative design and evaluation of imaging systems for researchers.

Molecular aspects of eye development and regeneration in the Australian redclaw crayfish,Cherax quadricarinatus

The compound eye evolved over 500 million years ago and enables mosaic vision in most arthropod species.The molecular regulation of the development of the compound eye has been primarily studied in the fruit fly Drosophila melanogaster.However,due to the nature of holometabolous insects halting growth after their terminal metamorphosis into the adult form,they lack the capacity to regenerate.Crustaceans,unlike holometabolous insects,continue to grow during adulthood,achieved through regular shedding of their exoskeleton,in a cyclic process known as molting.This therefore offers crustaceans as a highly suitable model to study ocular regeneration in the adult arthropod eye.We have assessed the regenerative capacity of the retinal section of the Cherax quadricarinatus(red-claw crayfish)eye,following ablation and successive post-metamorphic molts.This work then provides a transcriptomic description of the outer,pigmented retinal tissue(the ommatidia and lamina ganglionaris)and the basal,non-pigmented neuroendocrine ocular tissue(the X-organ Sinus Gland complex,hemiellipsoid body and optic nerve).Using comparative analysis,we identified all the transcripts in the C.quadricarinatus ocular transcriptome that are known to function in compound eye development in D.melanogaster.Differentially and uniquely transcribed genes of the retina are described,suggesting proposed mechanisms that may regulate ocular regeneration in decapod Crustacea.This research exemplifies the application C.quadricarinatus holds as an optimal model to study the regulation of ocular regeneration.Further in-depth transcriptomic analyses are now required,sampled throughout the regeneration process to better define the regulatory mechanism.

Deep learning enables parallel camera with enhanced-resolution and computational zoom imaging

High performance imaging in parallel cameras is a worldwide challenge in computational optics studies.However,the existing solutions are suffering from a fundamental contradiction between the field of view(FOV),resolution and bandwidth,in which system speed and FOV decrease as system scale increases.Inspired by the compound eyes of mantis shrimp and zoom cameras,here we break these bottlenecks by proposing a deep learning-based parallel(DLBP)camera,with an 8-μrad instantaneous FOV and 4×computational zoom at 30 frames per second.Using the DLBP camera,the snapshot of 30-MPs images is captured at 30 fps,leading to orders-of-magnitude reductions in system complexity and costs.Instead of directly capturing photography with large scale,our interactive-zoom platform operates to enhance resolution using deep learning.The proposed end-to-end model mainly consists of multiple convolution layers,attention layers and deconvolution layer,which preserves more detailed information that the image reconstructs in real time compared with the famous super-resolution methods,and it can be applied to any similar system without any modification.Benefiting from computational zoom without any additional drive and optical component,the DLBP camera provides unprecedented-competitive advantages in improving zoom response time(~100×)over the comparison systems.Herein,with the experimental system described in this work,the DLBP camera provides a novel strategy to solve the inherent contradiction among FOV,resolution and bandwidth.