Wide Field Of View Research Articles

First measurement of interplanetary scintillation with the ASKAP radio telescope: Implications for space weather

We report on a measurement of interplanetary scintillation (IPS) using the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope. Although this proof-of-concept observation utilised just 3 s of data on a single source, this is nonetheless a significant result, since the exceptional wide field of view of ASKAP, and this validation of its ability to observe within 10 degrees of the Sun, mean that ASKAP has the potential to observe an interplanetary coronal mass ejection (CME) after it has expanded beyond the field of view of white light coronagraphs, but long before it has reached the Earth. We describe our proof of concept observation and extrapolate from the measured noise parameters to determine what information could be gleaned from a longer observation using the full field of view. We demonstrate that, by adopting a ‘Target Of Opportunity’ (TOO) approach, where the telescope is triggered by the detection of a CME in white-light coronagraphs, the majority of interplanetary CMEs could be observed by ASKAP while in an elongation range <30°. It is therefore highly complementary to the colocated Murchison Widefield Array, a lower-frequency instrument which is better suited to observing at elongations >20°.

Fabrication of a bionic compound eye on a curved surface by using a self-assembly technique.

Microlens arrays on curved surfaces are regarded as critical elements of bionic compound eyes (BCEs), which exhibit the comparative advantages of a wide field of view and tracking fast-moving objects. However, the fabrication of a curved microlens array is still challenging. Along these lines, in this work, a straightforward, rapid, and low-cost technique for the fabrication of curved microlens arrays is reported by using the self-assembly technique. A reactive ion etching process treated the surface of the curved polydimethylsiloxane (PDMS) substrate to generate a hydrophobic-hydrophilic pattern. Then, the curved microlens array can be realized by dewetting a liquid glue onto the substrate using the dip-coating method and followed by crosslinking. The proposed BCE structure consists of 2400 microlenses (400 - µm diameter and 440 - µm center distance) arranged in a hexagonal configuration on a curved PDMS surface (34 - mm diameter and 40.4 - mm curvature radius). A field-of-view of 50° was demonstrated, which has potential applications in various fields including imaging sensors, medical diagnostics, machine vision systems, and photodetectors.

Investigations on simultaneous multi-color photometry survey for GEO region

Optical surveys play significant roles in space object monitoring and catalog, especially for some unique high-altitude regions like the Geosynchronous Earth Orbit (GEO) region. For object classes identification and space environment models development, besides the orbits additional information like physical properties are required. Non-resolving observation techniques like color photometry can provide such knowledge. Here simultaneous surveys for GEO region in g’r’i’ bands were performed utilizing the CHanging Event Survey (CHES) system of Purple Mountain Observatory. Based on the large amounts of images, the object detection, catalog correlation and multi-color photometry are performed consecutively. Due to the extremely wide field of view of CHES system, the simultaneous multi-band information of 1697 objects is obtained. The distribution and clustering behavior of their color indexes are preliminarily investigated, and the evolution of color with launch age is also analyzed. It is demonstrated that even for the same object class the distribution of color index may be different, and for various objects of the same class multiple clusters of color index are found. It indicates that the color photometry can help to classify object classes and provide useful information for correlating new observations with catalog.

Photometric characterization of Starlink satellite tracklets using RGB filters

The number of satellites orbiting the Earth has significantly increased and large constellations based on thousands of satellites are currently being designed and operated. Among them the Starlink project, owned by SpaceX, is in advanced phase. The massive presence of orbiting objects could have a negative impact on astronomical research. In the case of observations with long exposure times and/or wide field of view (FoV), numerous bright tracklets, caused by the reflection of sunlight on a transiting satellite, may appear in the images. For this reason, the Sapienza Space Systems and Space Surveillance Laboratory (S5Lab), which has been involved in research on space debris and space surveillance for many years, started a new research project on the photometric characterization of some satellites of the Starlink project, using red, green and blue filters and comparing the results with observations performed without filters in order to analyze the features of the transit of Starlink satellites. The observations will stress the high complexity of the Starlink satellites reflection pattern, producing interesting results concerned with the used filters and the observation geometry.

Design and collaborative optimization method of multilayer coatings to correct polarization aberration of optical systems.

Multilayer coatings induce a significant polarization aberration in optical systems with high numerical aperture (NA) and wide field of view, which will cause wavefront distortion and imaging degradation. Studies have used low-polarization coatings (LPC) design to reduce the coating-induced polarization aberration. However, the polarization aberration caused by LPC remain evident in systems with large incident angles and many coated surfaces. In this paper, a hybrid optimization algorithm (HOA) is proposed to enhance the design accuracy of LPC. Based on the HOA, a collaborative optimization method is developed to simultaneously design coatings with different polarization properties for multiple surfaces, which can correct polarization aberration by mutual compensation between the coated surfaces and other optical elements in a single system. Finally, a high NA lithographic lens is simulated as an example to verify the collaborative optimization method. The simulation demonstrates that this method is superior to conventional methods. This research provides a new way to correct the polarization aberration and is applicable to any systems coated with multilayer coatings.

Printing Polymeric Convex Lenses to Boost the Sensitivity of a Graphene-Based UV Sensor.

Ultraviolet (UV) is widely used in daily life as well as in industrial manufacturing. In this study, a single-step postprocess to improve the sensitivity of a graphene-based UV sensor is studied. We leverage the advantage of electric-field-assisted on-demand printing, which is simply applicable for mounting functional polymers onto various structures. Here, the facile printing process creates optical plano-convex geometry by accelerating and colliding a highly viscous droplet on a micropatterned graphene channel. The printed transparent lens refracts UV rays. The concentrated UV photon energy from a wide field of view enhances the photodesorption of electron-hole pairs between the lens and the graphene sensor channel, which is coupled with a large change in resistance. As a result, the one-step post-treatment has about a 4× higher sensitivity compared to bare sensors without the lenses. We verify the applicability of printing and the boosting mechanism by variation of lens dimensions, a series of UV exposure tests, and optical simulation. Moreover, the method contributes to UV sensing in acute angle or low irradiation. In addition, the catalytic lens provides about a 9× higher recovery rate, where water molecules inside the PEI lens deliver fast reassembly of the electron-hole pairs. The presented method with an ultimately simple fabrication step is expected to be applied to academic research and prototyping, including optoelectronic sensors, energy devices, and advanced manufacturing processes.

Inversion of the hybrid machine learning model to estimate leaf area index of winter wheat from GaoFen-6 WFV imagery

The leaf area index (LAI) is an important agroecological physiological parameter affecting vegetation growth and is an essential indicator for estimating crop growth. To apply the hybrid machine learning model to the remote sensing inversion of winter wheat LAI at three growth stages based on the wide field of view (WFV) of the GaoFen-6 (GF-6 WFV) images, the Xiangfu District in the east of Kaifeng City, Henan Province, was selected as the testing region. The LAI values, which were simulated using the CERES-wheat model, were an input for the PROSAIL model to simulate spectral reflectance. Different machine learning regression algorithms (MLRA) were trained with simulated spectra reflectance by PROSAIL and subsequently applied to the GF-6 WFV reflectance spectra. The random forest regression (RFR) model achieved reliable LAI estimates at the three growth stages. CERES-wheat and PROSAIL preserved the most informative spectra reflectance for LAI estimation so that each RFR could achieve satisfactory estimation results. The hybrid machine learning model could accurately reverse the growth state of winter wheat in three growth stages.

Visible imaging system with changeable field of view on the HL-2A tokamak.

A new visible imaging system characterizing a flexible optical design and delivering high resolution frames is established on the HL-2A tokamak. It features a modular configuration, consisting of a front-end imaging lens, a set of bilateral telecentric relay lenses, and a camera. To avoid the effects of plasma radiation (x and gamma-rays) and magnetic field variation on the camera, it should be away from the coils. Therefore, the length of the relay lenses determines the total size of the imaging system. The main feature of this imaging system is to realize the variation of field of view (FOV) by interchanging the front-end prime lenses or by using a zoom lens directly rather than designing the optical system afresh, which lowers the cost drastically. The primary purpose of varying FOV is to enrich the versatility of this system, i.e., focusing on a narrow FOV such as gas puff imaging or a wide FOV such as the plasma cross sections. During the HL-2A experiments, this visible imaging system is used to provide high quality pictures of the plasma-wall interaction, divertor detachment, pellet injections, and so on. The frames confirmed that a strong radiation close to the X point is correlated with the completely detached inner target.

A High-Speed Chip-Scale Rotary Polygon Optical Scanner Based on a Micromotor Integrated With a Micro-Polyhedron Mirror

Micro-opto-electro-mechanical systems (MOEMS) based mirrors with a suitable actuation range are often used for optical beam scanning applications. While several MOEMS scanners have been reported, they often have limitations with respect to their range of motion, field of view, mass, size and fabrication cost. In this work, we present a rotary micro-polygon scanner based on an electrostatic variable capacitance micromotor for laser beam steering applications. The miniaturized scanner consists of a hollow micro-polyhedron mirror with a base radius of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$200 {\mu }\text{m}$ </tex-math></inline-formula> and a height of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$400 {\mu }\text{m}$ </tex-math></inline-formula> . It is mounted on the rotor of a variable capacitance micromotor using an epoxy-based adhesive. The rotor has a diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$600 {\mu }\text{m}$ </tex-math></inline-formula> and is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.5 {\mu }\text{m}$ </tex-math></inline-formula> thick. The micromotor was fabricated using a commercial three-layer polysilicon surface micro-machining process (PolyMUMPs) and the micro-polyhedrons were fabricated using a commercial bulk micro-machining process (PiezeoMUMPs). After fabrication of the components, the micro-scanner was assembled and operated under atmospheric conditions using a three-phase square wave excitation ranging from 0 V to 200 V and achieved rotational speeds of up to 2100 rpm. An optical laser beam with a wavelength of 632 nm was reflected off the sidewall of the rotating micro-polyhedron, achieving an experimentally measured scanning angular range of 57.88°, an angular scan rate of 220 radians per second and a scan speed of 25,200 lines per minute or 420 lines per second with a 12 sided micro-mirror. The ratio of the output power over the input optical power is measured over a scanning range of 22°, which is limited by the size of the photo-detector, yielding a ratio spanning from 0.18 to 0.22. This rotary micro-scanner can provide high scanning speeds and a wide scanning field of view with a footprint of 1.25 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a thickness of 0.83 mm, which is suitable to implement chip-level high-performance micro-beam steering systems for various applications. [2022-0020]

Gaia EDR3 comparative study of protoplanetary disk fractions in young stellar clusters

Context. The lifetime of protoplanetary disks around young stars limits the timescale of planet formation. A disk dissipation timescale ≤10 Myr was inferred from surveys that count the relative number of stars with disks – the disk fraction – in young stellar clusters with different ages. However, most previous surveys focused on the compact region within ∼2 pc of the clusters’ centers, for which the disk fraction information about the outer part is practically absent. Aims. We aim to test if disk fraction estimates change when inferred from an extended region around the clusters’ centers. Methods.Gaia EDR3 data and a best-suited, Virtual Observatory (VO)-based tool – Clusterix – are used to identify member stars for a representative sample of 19 young stellar clusters considering two concentric fields of view (FOVs) with radii of ∼20 pc and ∼2 pc. Inner-disk fractions associated with each FOV are identically derived from 2MASS color-color diagrams and compared to each other. Results. Although the density of members is smaller in the periphery, the absolute number of member stars is typically ∼5 times larger at distances farther than ∼2 pc from the clusters’ centers. In turn, our analysis reveals that the inner disk fractions inferred from the compact and the extended regions are equal within ∼±10%. A list of member and disk stars identified in each cluster is provided and stored in a VO-compliant archive, along with their membership probabilities, angular distances to the center, and Gaia and near-infrared data. Averaged values and plots that characterize the whole clusters are also provided, including Hertzsprung-Russell diagrams based on Gaia colors and absolute magnitudes for the sources with known extinction. Conclusions. Our results cover the largest fields ever probed when dealing with disk fractions for all clusters analyzed, and imply that their complete characterization requires the use of wide FOVs. However, the comparative study does not support a previous hypothesis that disk fractions should be significantly larger when extended regions are considered. The resulting database is a benchmark for future detailed studies of young clusters, whose disk fractions must be accurately determined by using multiwavelength analysis potentially combined with data from upcoming Gaia releases.

Searching for stellar flares from low-mass stars using ASKAP and TESS

ABSTRACT Solar radio emission at low frequencies (&amp;lt;1 GHz) can provide valuable information on processes driving flares and coronal mass ejections (CMEs). Radio emission has been detected from active M dwarf stars, suggestive of much higher levels of activity than previously thought. Observations of active M dwarfs at low frequencies can provide information on the emission mechanism for high energy flares and possible stellar CMEs. Here, we conducted two observations with the Australian Square Kilometre Array Pathfinder Telescope totalling 26 h and scheduled to overlap with the Transiting Exoplanet Survey Satellite Sector 36 field, utilizing the wide fields of view of both telescopes to search for multiple M dwarfs. We detected variable radio emission in Stokes I centred at 888 MHz from four known active M dwarfs. Two of these sources were also detected with Stokes V circular polarization. When examining the detected radio emission characteristics, we were not able to distinguish between the models for either electron cyclotron maser or gyrosynchrotron emission. These detections add to the growing number of M dwarfs observed with variable low-frequency emission.

Multi-parameter and multi-objective optimization of stratified OLEDs over wide field-of-view considering thickness tolerance.

Poor wide field-of-view (FOV) performances and low production yields are major factors that restrict the application of organic light-emitting diodes (OLEDs) in large-size panels. In this paper, we propose an optimization and analysis method to improve optical performances of stratified OLEDs over wide FOV with consideration of the thickness tolerance in the practical production process. With key optical performance parameters defined using the angle-dependent luminescence spectra, including the external quantum efficiency (EQE), current efficiency (CE), just noticeable color difference (JNCD), and the color coordinates, the optimization of OLEDs over wide FOV is described as a multi-parameter and multi-objective optimization problem which is accomplished by the genetic algorithms (GAs). Further, the thickness tolerance is introduced to improve the structure stability considering thickness fluctuations in the practical production process. Appropriate thickness tolerances can be determined to achieve stable structures for the OLED device by defining and analyzing the distributions of preference regions of the GA output noninferior solutions and the correlation coefficients between the layer thicknesses. Based on the proposed methods, high-throughput simulations are carried out on a typical Green Bottom-emitting OLED (G-BOLED) to design a stable device structure with high-performances. Experimental results demonstrate that compared with the initial device, the performances of the optimized device have been significantly improved, with the CE improved by over 30% in the normal direction, the EQE improved by over 20%, and the JNCD reduced from 4.45 to 1.36 over the whole FOV of 0-60°. In addition, within the thickness fluctuation in the practical process, optimized devices can strictly satisfy the "Best" preferred region, indicating that the structure is more stable against thickness fluctuations in the practical production process. The proposed optimization method can simultaneously improve optical performances over wide FOV and provide a stable structure for stratified OLEDs, and it therefore can be expected to improve the production yields and promote the OLEDs applied to large-size panels.

Label-free, real-time detection of perineural invasion and cancer margins in a murine model of head and neck cancer surgery

Surgical management of head and neck cancer requires a careful balance between complete resection of malignancy and preservation of function. Surgeons must also determine whether to resect important cranial nerves that harbor perineural invasion (PNI), as sacrificing nerves can result in significant morbidity including facial paralysis. Our group has previously reported that Dynamic Optical Contrast Imaging (DOCI), a novel non-invasive imaging system, can determine margins between malignant and healthy tissues. Herein, we use an in vivo murine model to demonstrate that DOCI can accurately identify cancer margins and perineural invasion, concordant with companion histology. Eight C3H/HeJ male mice were injected subcutaneously into the bilateral flanks with SCCVIISF, a murine head and neck cancer cell line. DOCI imaging was performed prior to resection to determine margins. Both tumor and margins were sent for histologic sectioning. After validating that DOCI can delineate HNSCC margins, we investigated whether DOCI can identify PNI. In six C3H/HeJ male mice, the left sciatic nerve was injected with PBS and the right with SCCVIISF. After DOCI imaging, the sciatic nerves were harvested for histologic analysis. All DOCI images were acquired intraoperatively and in real-time (10 s per channel), with an operatively relevant wide field of view. DOCI values distinguishing cancer from adjacent healthy tissue types were statistically significant (P < 0.05). DOCI imaging was also able to detect perineural invasion with 100% accuracy compared to control (P < 0.05). DOCI allows for intraoperative, real-time visualization of malignant and healthy tissue margins and perineural invasion to help guide tumor resection.

A wide-field and high-resolution lensless compound eye microsystem for real-time target motion perception

Optical measurement systems suffer from a fundamental tradeoff between the field of view (FOV), the resolution and the update rate. A compound eye has the advantages of a wide FOV, high update rate and high sensitivity to motion, providing inspiration for breaking through the constraint and realizing high-performance optical systems. However, most existing studies on artificial compound eyes are limited by complex structure and low resolution, and they focus on imaging instead of precise measurement. Here, a high-performance lensless compound eye microsystem is developed to realize target motion perception through precise and fast orientation measurement. The microsystem splices multiple sub-FOVs formed by long-focal subeyes, images targets distributed in a panoramic range into a single multiplexing image sensor, and codes the subeye aperture array for distinguishing the targets from different sub-FOVs. A wide-field and high resolution are simultaneously realized in a simple and easy-to-manufacture microelectromechanical system (MEMS) aperture array. Moreover, based on the electronic rolling shutter technique of the image sensor, a hyperframe update rate is achieved by the precise measurement of multiple time-shifted spots of one target. The microsystem achieves an orientation measurement accuracy of 0.0023° (3σ) in the x direction and 0.0028° (3σ) in the y direction in a cone FOV of 120° with an update rate ~20 times higher than the frame rate. This study provides a promising approach for achieving optical measurements with comprehensive high performance and may have great significance in various applications, such as vision-controlled directional navigation and high-dynamic target tracking, formation and obstacle avoidance of unmanned aerial vehicles.

Hyperbolic metamaterial-assisted structured illumination microscopy using periodic sub-diffraction speckles

Structured illumination microscopy (SIM), as a wide-field, rapid, super-resolution imaging technology, is widely employed in the field of biology. In this work, we propose a hyperbolic metamaterial (HMM)-assisted super-resolution structured illumination microscopy technique. By utilizing the HMM, a sub-diffraction illumination pattern of bulk plasmon polariton (BPP) with pure and higher spatial frequency replaces the conventional laser interference fringes, thus the imaging resolution of BPPSIM could surpass that of conventional SIM and reach 65 nm for HMM with 8-layers periodic structure. Moreover, an HMM with 10-layers aperiodic structure designed with particle swarm optimization was obtained, and BPPSIM could bring the imaging resolution down to 60 nm (1/9 of the fluorescence wavelength), which is a 3.3-fold improvement compared with the diffraction-limited image. This BPPSIM would provide a super-resolution, wide field of view, and good bio-compatibility approach in biological imaging.

Elucidation of frictional properties between rubber and flooring using a laser microscope with wide field of view

We investigate the measurement of real contact area, denoted by Ar, between various floor materials and rubber. Observation of Ar plays an important role for better understanding of frictional force. The Ar between them, however, has yet to be observed over regions wider than what an optical microscope can cover. Current optical microscopy techniques are limited by the measurement time required to observe the whole apparent contact area. Further, it is difficult to reproduce actual contact situations between the rubber and the floor materials because at least one of the contacting specimens must be transparent. Usually, glass plates much harder than rubber are used as counter specimens. In this study, we observed the Ar between a transparent silicone rubber and the various floor materials by using a laser microscope with a wide field of view, allowing us to observe the whole apparent contact area of 9 mm × 7 mm for a very short time. By using transparent rubber, we were able to reproduce the actual contact situations of the rubber-floor specimens, which is impossible with glass plates. The measurement of Ar when the apparent contact area was too small suffered from large fluctuations in measurement values due to waviness of the floor specimen. We investigated the apparent contact area required to accurately understand the relationship between frictional force and Ar and clarified the influence of waviness of the floor materials on the distribution of Ar.

Optical system for the measurement of the surface topography of additively manufactured parts

Additive manufacturing (AM) is now regularly used for customised fabrication of parts with complex shapes and geometries. However, the large range of relevant scales, high slopes, step-like transitions, undercuts, alternation between dark and overly bright regions and other complex features present on the surfaces, in particular of metal additive parts, represent a significant challenge for current optical measurement technologies. Measuring surfaces with such complex features requires high numerical aperture (NA) optics, and state-of-the-art systems commonly include optics that can only reliably acquire surface topographies over a small field of view (FOV), typically tens or hundreds of micrometers. Such measurements are often insufficient for practical applications. Here, we present an optical system that features a large NA (0.3) and a wide FOV mm, capable of measuring AM parts in a single measurement, without the need for lateral stitching to increase the FOV. The proposed system exhibits optical properties that provide facility for large-field, high-resolution measurement of industrially-produced additively manufactured parts.

(Digital Presentation) Garnet Structure with UVC and UVB Dual-Band Persistent Luminescence

While persistent luminescence (PersL) at visible and infrared are frequently reported in lanthanide-doped inorganic phosphors for night-vision displays and bio-imaging, an awareness to ultraviolet (UV) PersL remains much less. Here, we have designed Pr3+-doped (Ca1.5Y1.5)(Al3.5Si1.5)O12 (CYAS-Pr) through co-substituting Ca2+-Si4+ into a well-known garnet structure, Y3Al5O12. By the strategy of Ca2+-Si4+ co-substitution, the CYAS-Pr exhibits lattice distortion and subsequently an unprecedent UVC and UVB dual-band PersL with maxima at 266 and 311 nm for 12 hours after charged by UV irradiation due to creation of intrinsic trapping centers. The unique PersL performance is contributed by an existence of two different Pr3+ environments at Ca2+ and Y3+ sites of the CYAS host. The CYAS-Pr shows efficient dual information storage and precise long-distance self-sustained “solar-blind” imaging capabilities in a wide and bright field of view. It is expected that the UVC and UVB dual-band PersL CYAS-Pr will find more applications and trigger further exploration towards persistent sterilization and persistent photocatalysis.

High-performance lensless diffraction imaging from diverse holograms by three-dimensional scanning.

For lensless diffraction imaging, it is a challenging dilemma to achieve a large field of view (FOV) and high resolution with a small amount of data at the same time. Ptychography can reconstruct the high-resolution image and illumination light simultaneously. But the illumination is limited to a small size by a probe in typical ptychography. For large samples, it takes much time to collect abundant patterns and has strict requirements for the computing power of computers. Another widely applied method, multi-height measurement, can realize a wide FOV with several holograms. But, the recovered image is easily destroyed by the background noise. In this Letter, a lensless diffraction imaging method by three-dimensional scanning is proposed. All positions of the object are different in three directions instead of scanning schemes only on a plane or along the optic axis, so more diversity of diffraction information is obtained. We apply the illumination without the limit of a confined aperture, which means that the imaging FOV of a pattern is equal to the size of the utilized image sensor. In comparison with the multi-height method, our method can separate the illumination background noise from the retrieved object. Consequently, the proposed method realized high resolution and contrast, large FOV, and the removal of background noise simultaneously. Experimental validations and comparisons with other methods are presented.

Optical imaging system for an all-time star sensor based on field of view gated technology.

The wide field of view (FOV) of traditional star sensor optical systems restricts the ability to suppress atmospheric background. An optical imaging system for an all-time star sensor based on FOV gated technology is proposed. In this system, a wide FOV telescope is used to observe a large sky area containing multiple stars. A microlens and microshutter array is employed to subdivide the wide FOV and gate a narrow FOV to suppress atmospheric background radiation. Assisted by a common imaging lens, each set of microlens and microshutter elements corresponds to a FOV gated imaging channel. With the rapid switching of gated FOV, multiple stellar images are obtained on a common detection during daytime. As an example, a FOV gated optical imaging system with 0.4° gated FOV and 61 imaging channels is designed. In addition, a simplified prototype is developed, and a preliminary experiment of FOV gated imaging is performed near the ground. The results verify the capability of multiple stellar detections during daytime. The proposed optical imaging system has a strong capability of suppressing atmospheric background radiation and provides sufficient FOV gated imaging channels to enhance the probability of detecting multiple stars. It provides an effective technical way to develop all-time star sensors based on star pattern recognition and enables a completely autonomous attitude determination possible for platforms inside the atmosphere during daytime.