Structure Of Compound Eye Research Articles

Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities

Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.

Design and Fabrication of an Artificial Compound Eye for Multi-Spectral Imaging.

The artificial compound eye (ACE) structure is a new type of miniaturized, lightweight and intelligent imaging system. This paper has proposed to design a multi-spectral ACE structure to enable the structure to achieve multi-spectral information on the basis of imaging. The sub-eyes in the compound eye structure have been designed as diffractive beam splitting lenses with the same focal length of 20 mm, but with the different designed center wavelengths of 650 nm, 532 nm, and 445 nm, respectively. The proximity exposure lithography and reactive ion etching process were used to prepare the designed multi-spectral ACE structure, and the spectral splitting and multi-spectral imaging experiments were carried out to verify the multi-spectral imaging function of the structure without axial movement. Furthermore, the structure can be designed according to actual requirements, which can be applied to covert reconnaissance, camouflage identification, gas leakage or other fields.

Optimization of positioning technology of aspheric compound eyes with variable focal length

For single non-uniform surface compound eyes cannot achieve zoom imaging, resulting in poor imaging and other issues, a new type of aspherical artificial compound eye structure with variable focal length is proposed in this paper. The structure divides the surface compound eye into three fan-shaped areas, and different focal lengths of the micro-lens in different area make the artificial compound eye zoom in a certain range. The focal length and size of the micro-lens are determined by the area and the location of the micro-lens. The optimization of aspherical array of the micro-lens is calculated and the spherical aberration in each area is reduced to one percent of the initial value. Through simulation analysis, the designed artificial compound eye structure can realize the focal length adjustment, and effectively reduce the problem of the poor imaging quality of the curved compound eye edge. As a result, the aspherical artificial compound eye sample with the number of eyes of n=61 and the diameter of the base of 8.66mm was prepared using the molding method. The mutual relationship between the eyes of the child was calibrated and a mathematical model for the simultaneous identification of multiple sub eyes was established. An artificial compound eye positioning experimental system with the error value less than 10% was set up through a number of micro-lens capture target point settlement coordinates.

Design and Fabrication of a Three-Dimensional Artificial Compound Eye Using Two-Photon Polymerization.

Microlens arrays have been widely used in the fields of micro-optics because of the advantages of their high diffraction efficiency, high fill factor, and wide operating band. However, the microlens array still has problems with its smaller field of view (FOV) and lower utilization of light energy. In this paper, a 3D compound eye system consisting of a microlens array and a pinhole array was designed according to the optical principle of insect compound eye. The artificial compound eye structure was processed in two-photon polymerization processing technology. Ray tracing and optical system simulation of the designed artificial compound eye structure were performed. The results showed that the artificial compound eye structure had a wider FOV and higher light energy utilization than a conventional 2D microlens array. This thesis may lay a theoretical foundation for the structural optimization design of microlens arrays.

The Design and Positioning Method of a Flexible Zoom Artificial Compound Eye.

The focal lengths of the sub-eyes in a single-layer uniform curved compound eye are all the same, resulting in poor imaging quality for the compound eye. A non-uniform curved compound eye can effectively solve the problem of poor edge-imaging quality, however, it suffers from a large spherical aberration, and is unable to achieve zoom imaging. To solve these problems, a new type of aspherical artificial compound eye structure with variable focal length is proposed in this paper. The structure divides the surface compound eye into three fan-shaped areas with different focal lengths of the microlens in different areas, which allow the artificial compound eye to zoom in a certain range. The focal length and size of the microlens is determined by the area and the location of the microlens. The aspherical optimization of the microlens is calculated, and spherical aberration in each area is reduced to one percent of the initial value. Through simulation analysis, the designed artificial compound eye structure realizes focal length adjustment and effectively reduces the problem of the poor imaging quality of the curved compound eye edge. As a result, an aspherical artificial compound eye sample—where the number of sub-eyes is n = 61, and the diameter of the base is Φ = 8.66 mm—was prepared by using a molding method. Additionally, the mutual relationship between the eyes of the child was calibrated, and hence, a mathematical model for the simultaneous identification of multiple sub-eyes was established. This study set up an experimental artificial compound eye positioning system, and through a number of microlens capture target point settlement coordinates, achieved an error value of less than 10%.

Design and fabrication of a multifocal bionic compound eye for imaging

Miniaturized bionic compound eyes featured with multi-aperture imaging have potential applications in the areas of micro opto-electro-mechanical-system. In this manuscript, we present a novel structure of the bionic compound eye with multiple focal lengths consists of an array of individual lenses with 1000 µm diameter. The simulation results of the designed multifocal bionic compound eye (MBCE) with two focal lengths of 190 mm and 44.4 mm demonstrate excellent two-order focusing abilities. Moving mask exposure technology was used to fabricate the designed MBCE with the corresponding imaging experiments conducted to validate the two-order imaging ability of the fabricated MBCE. Experimental results revealed that the developed structure has potential applications in diverse optical imaging systems such as three-dimensional imaging and real-time detection of unconfined or fluctuating targets.

A Bionic Polarization Navigation Sensor Based on Polarizing Beam Splitter

Polarization navigation has been an active research direction in navigation fields due to its autonomy and robustness, especially in global navigation satellite system-denied environment. Most existing bionic polarization sensing schemes employed the linear polarizer as the analyzer. However, the quadrature error between the two sets of mutually orthogonal polarizers is usually inevitable, which may cause the sensor output distortion and directly affect the performance of polarization navigation sensors. In this paper, inspired by the special polarization-sensitive structure of insect compound eyes, a polarizing beam splitter (PBS) based polarization navigation sensor is designed. Concerned with the optical path coupling and extinction ratio inconsistency problem between the transmitted beam and the reflected one of the PBS, the novel sensor model is established, where we introduce a coupling coefficient to solve the problems mentioned above. An algorithm of computing the polarization degree and the polarization azimuth angle is presented based on the model. The unscented Kalman filter calibration method is adopted and the calibration experiments are carried out. Finally, the outdoor static accuracy of the sensor is tested, where the results showed that the sensor designed in this paper achieved high accuracy and good stability for a long time.

Rotenone Induced Alterations in Lifecycle Parameters and Compound Eye Morphology of Drosophila Melanogaster

Rotenone is a widely used natural pesticide and piscicide and a potent inhibitor of mitochondrial complex I (NADHquinone reductase) that elicits the degeneration of dopaminergic neurons. Present study explored the adverse effect of rotenone at concentrations far below the reported LC 50 on several life cycle parameters and on the compound eye structure of a non-target insect, Drosophila melanogaster . Newly hatched first instar larvae were introduced in Drosophila food medium containing different concentrations (50, 100, 150, 200, 250 μg/L) of rotenone. Different life cycle parameters were recorded. Emerged adult flies were collected and studied under Scanning electron microscope. Student's t-test was performed to explore significant difference and changes in both life cycle parameter and eye architecture. Treated groups showed significant delay (p<0.05 level) in larval duration, pupal duration, and in emergence of flies when compared with the control groups. Delay in life cycle parameters significantly increased with increase of rotenone exposure. Interestingly, the compound eye structure of the treated flies was seen to be affected by rotenone. Thus these results clearly demonstrate that chronic exposure to rotenone can alter the structure and lifecycle of a non-target organism like Drosophila at sub-lethal concentrations. Thus rotenone in Drosophila at sub-lethal concentrations might be the reason for developmental toxicity.

Conservative whole-organ scaling contrasts with highly labile suborgan scaling differences among compound eyes of closely related Formica ants.

Static allometries determine how organ size scales in relation to body mass. The extent to which these allometric relationships are free to evolve, and how they differ among closely related species, has been debated extensively and remains unclear; changes in intercept appear common, but changes in slope are far rarer. Here, we compare the scaling relationships that govern the structure of compound eyes of four closely related ant species from the genus Formica. Comparison among these species revealed changes in intercept but not slope in the allometric scaling relationships governing eye area, facet number, and mean facet diameter. Moreover, the scaling between facet diameter and number was conserved across all four species. In contrast, facet diameters from distinct regions of the compound eye differed in both intercept and slope within a single species and when comparing homologous regions among species. Thus, even when species are conservative in the scaling of whole organs, they can differ substantially in regional scaling within organs. This, at least partly, explains how species can produce organs that adhere to genus wide scaling relationships while still being able to invest differentially in particular regions of organs to produce specific features that match their ecology.

Fly compound-eye inspired inorganic nanostructures with extraordinary visible-light responses

Inorganic bio-inspired nanomaterials, which integrate the unique properties of metal oxide nanomaterials and the features of well-evolved biological structures and functions, are a novel direction towards mining the potential of existing materials to further enhance the performance of various microelectronic and energy harvesting, conversion, and storage devices, although the facile fabrication of bio-inspired materials still remains a major challenge. We noticed that some compound eyes presented extremely strong responses to light and displayed beautiful colours and patterns, which inspired us to design novel photonic materials. In this study, we fabricated fly compound-eye inspired ZnO nanomaterials in the forms of either isolated microspheres or highly-ordered coatings grown in-situ, in which the three-zone structures were similar to the anatomical structure of the biological compound eyes, including an outermost faceted microlens array, a middle rhabdom-like channel layer, and a central hollow zone. The bio-inspired nanomaterials, as we expected, presented extraordinary visible-light response behaviour and would make it possible to capture energy across a wide solar spectrum with a single semiconductor material. This study thus paves the way to further improving the performance of the current photoelectronic and energy harvesting, conversion, and storage devices.

Flight Morphology, Compound Eye Structure and Dispersal in the Bog and the Cranberry Fritillary Butterflies: An Inter- and Intraspecific Comparison.

Understanding dispersal is of prime importance in conservation and population biology. Individual traits related to motion and navigation during dispersal may differ: (1) among species differing in habitat distribution, which in turn, may lead to interspecific differences in the potential for and costs of dispersal, (2) among populations of a species that experiences different levels of habitat fragmentation; (3) among individuals differing in their dispersal strategy and (4) between the sexes due to sexual differences in behaviour and dispersal tendencies. In butterflies, the visual system plays a central role in dispersal, but exactly how the visual system is related to dispersal has received far less attention than flight morphology. We studied two butterfly species to explore the relationships between flight and eye morphology, and dispersal. We predicted interspecific, intraspecific and intersexual differences for both flight and eye morphology relative to i) species-specific habitat distribution, ii) variation in dispersal strategy within each species and iii) behavioural differences between sexes. However, we did not investigate for potential population differences. We found: (1) sexual differences that presumably reflect different demands on both male and female visual and flight systems, (2) a higher wing loading (i.e. a proxy for flight performance), larger eyes and larger facet sizes in the frontal and lateral region of the eye (i.e. better navigation capacities) in the species inhabiting naturally fragmented habitat compared to the species inhabiting rather continuous habitat, and (3) larger facets in the frontal region in dispersers compared to residents within a species. Hence, dispersers may have similar locomotory capacity but potentially better navigation capacity. Dispersal ecology and evolution have attracted much attention, but there are still significant gaps in our understanding of the mechanisms of dispersal. Unfortunately, for many species we lack detailed information on the role of behavioural, morphological and physiological traits for dispersal. Our novel study supports the existence of inter- and intra-specific evolutionary responses in both motion and navigation capacities (i.e. flight and eye morphology) linked to dispersal.

Colony-Level Differences in the Scaling Rules Governing Wood Ant Compound Eye Structure.

Differential organ growth during development is essential for adults to maintain the correct proportions and achieve their characteristic shape. Organs scale with body size, a process known as allometry that has been studied extensively in a range of organisms. Such scaling rules, typically studied from a limited sample, are assumed to apply to all members of a population and/or species. Here we study scaling in the compound eyes of workers of the wood ant, Formica rufa, from different colonies within a single population. Workers’ eye area increased with body size in all the colonies showing a negative allometry. However, both the slope and intercept of some allometric scaling relationships differed significantly among colonies. Moreover, though mean facet diameter and facet number increased with body size, some colonies primarily increased facet number whereas others increased facet diameter, showing that the cellular level processes underlying organ scaling differed among colonies. Thus, the rules that govern scaling at the organ and cellular levels can differ even within a single population.

Compound eye and ocellar structure for walking and flying modes of locomotion in the Australian ant, Camponotus consobrinus.

Ants are unusual among insects in that individuals of the same species within a single colony have different modes of locomotion and tasks. We know from walking ants that vision plays a significant role in guiding this behaviour, but we know surprisingly little about the potential contribution of visual sensory structures for a flying mode of locomotion. Here we investigate the structure of the compound eye and ocelli in pedestrian workers, alate females and alate males of an Australian ant, Camponotus consobrinus, and discuss the trade-offs involved in optical sensitivity and spatial resolution. Male ants have more but smaller ommatidia and the smallest interommatidial angles, which is most likely an adaptation to visually track individual flying females. Both walking and flying forms of ants have a similar proportion of specialized receptors sensitive to polarized skylight, but the absolute number of these receptors varies, being greatest in males. Ocelli are present only in the flying forms. Each ocellus consists of a bipartite retina with a horizon-facing dorsal retina, which contains retinula cells with long rhabdoms, and a sky-facing ventral retina with shorter rhabdoms. We discuss the implications of these and their potential for sensing the pattern of polarized skylight.

Differential scaling within an insect compound eye.

Environmental and genetic influences cause individuals of a species to differ in size. As they do so, organ size and shape are scaled to available resources whilst maintaining function. The scaling of entire organs has been investigated extensively but scaling within organs remains poorly understood. By making use of the structure of the insect compound eye, we show that different regions of an organ can respond differentially to changes in body size. Wood ant (Formica rufa) compound eyes contain facets of different diameters in different regions. When the animal body size changes, lens diameters from different regions can increase or decrease in size either at the same rate (a ‘grade’ shift) or at different rates (a ‘slope’ shift). These options are not mutually exclusive, and we demonstrate that both types of scaling apply to different regions of the same eye. This demonstrates that different regions within a single organ can use different rules to govern their scaling, responding differently to their developmental environment. Thus, the control of scaling is more nuanced than previously appreciated, diverse responses occurring even among homologous cells within a single organ. Such fine control provides a rich substrate for the diversification of organ morphology.

Exceptional preservation of eye structure in arthropod visual predators from the Middle Jurassic.

Vision has revolutionized the way animals explore their environment and interact with each other and rapidly became a major driving force in animal evolution. However, direct evidence of how ancient animals could perceive their environment is extremely difficult to obtain because internal eye structures are almost never fossilized. Here, we reconstruct with unprecedented resolution the three-dimensional structure of the huge compound eye of a 160-million-year-old thylacocephalan arthropod from the La Voulte exceptional fossil biota in SE France. This arthropod had about 18,000 lenses on each eye, which is a record among extinct and extant arthropods and is surpassed only by modern dragonflies. Combined information about its eyes, internal organs and gut contents obtained by X-ray microtomography lead to the conclusion that this thylacocephalan arthropod was a visual hunter probably adapted to illuminated environments, thus contradicting the hypothesis that La Voulte was a deep-water environment.

Precision UV imprinting system for parallel fabrication of large-area micro-lens arrays on non-planar surfaces

This paper reports a vacuum-assisted UV imprinting system for parallel fabrication of micro-lens arrays on a spherical dome for artificial compound eye applications. Artificial compound eyes are a kind of micro-optics structure inspired by insect eyes. They offer unique optical characteristics, e.g., wide field of view (FOV), high sensitivity and light weight, in a compact arrangement with miniaturized lens arrays on a curved surface. In practice, it has been a great challenge to precisely fabricate micro-lens arrays on curved substrates at reasonable cost. The UV imprinting system was developed to ensure conformal contact between a soft elastomeric stamp and a convex substrate, i.e., dome, coated with UV-curable resins. The pressure-driven stamp enables large-area direct formation of high fill factor hexagonal micro-lens arrays through soft UV imprint processes. The geometrical characteristics, surface quality and optical properties of the micro-lens array were characterized quantitatively, e.g., NA=0.06; RMS∼λ/50. Lastly, the optical performance of the artificial compound eyes was demonstrated by an ultra-wide angle imaging experiment under uniform illumination. The vacuum imprinting system presents a new manufacturing platform for fabricating 3-dimensional structures on nonplanar substrates in a parallel and cost effective way. The fabricated compound eye structure will be particularly useful in the areas of multi-channel imaging, machine vision, and surveillance.

Mechanics and optics of stretchable elastomeric microlens array for artificial compound eye camera

Compound eye-inspired imaging devices can find vast applications due to their remarkable imaging characteristics, such as extremely large field of view angle, low aberrations, high acuity to motion, and infinite depth of field. Recently, researchers have successfully developed a digital camera that resembles the structure and functions of apposition compound eyes of arthropod, by combining an elastic array of microlenses with a stretchable array of photodetectors in their planar form and then transforming into a hemispherical shape. Designing an elastomeric microlens array that can be mechanically stretched to very large extent without deteriorating the optical performance is critical to this development. In this study, mechanics and optics of the stretchable microlens array, in which each hemispherical microlens sits on top of a supporting post connected to a base membrane, are studied. The results show that proper designs of the microlenses, supporting posts and base membrane are critically important to meet both mechanical and optical requirements simultaneously. This study can have important implications in not only the design of artificial compound eye cameras, but also other developments that require stretchable optical elements.

Description and interpretation of the internal structure of a Cambrian crustacean compound eye

Description and interpretation of the internal structure of a Cambrian crustacean compound eye

大视场复眼结构图像处理算法研究

For the large field of view compound eye structure with multi-dimensional sub-eye imaging channels aranged on a curve surface, the segmentation-rotation-projection image processing algorithm was presented to realize a large field of view synthesized of multi-channels. By confirming the arrangement characteristics of the compound eye structure, the relation among all sub-eye images captured by corresponding imaging channels was analyzed and the overlap regions between nearby sub-eye images were eliminated. Meanwhile, by using the principle of geometrical optics and imaging optics, the relation between the sub-eye images and the three-dimensional projection space was studied to achieve the large field of view of two-dimensional sub-eye images synthesized in a three-dimensional space. An artificial compound eye consisted of 37 lenses with field of view over 118 degrees was fabricated and the corresponding sub-eye images captured by the fabricated compound eye structure were processed based on the presented algorithm. The results show that the resolution of the sub-eye images can be ensured of no decrease during the image processing precedure and the algorithm can effectively realise a large field of view synthesized of multi-channel images meeting the practical requirements with high visual effect. All of the above studies could put forword the application of the compound eye imaging system.

各波長LEDに対するトビイロウンカの誘引行動と複眼構造およびオプシン遺伝子

イネ害虫トビイロウンカの光応答とそれに関連する分子に関する基礎的な知見を得るために，フォトン数を合わせられるLEDを用いての誘引実験，オプシン遺伝子同定および複眼の構造解析を行った．暗箱内での粘着板を用いた実験では，一方向からの光照射の場合は365–735 nmの広い波長範囲でトビイロウンカの誘引が見られた．また，両方向から等フォトンの光を照射した場合，選好性は 365 nm＝385 nm＞470 nm＝525 nm＞白色LED＝590 nm＞660 nm＞735 nm＞850 nm の順に有意に高かった．トビイロウンカ複眼の分光感度は520 nmに高いピークと360 nm にそれより低いピークが見られ，660 nm以上の長波長に対しての光受容感度は非常に低かった．トビイロウンカの光受容遺伝子は，長波長オプシン1種とUVオプシン遺伝子2種が見つかった．長波長オプシンは複眼の全体と単眼で，UVオプシン1は触角周縁部の下側で，UVオプシン2は複眼の全体で発現していた．ウンカ複眼の個眼は少なくとも8個の視細胞からなっていた．