Object re-identification(ReID) technology aims to match the same object captured by cameras across different areas at different time.The key is to distinguish different objects through fine-grained ...differences between different individuals, which is widely used in security control, criminal investigation and monitoring, etc.Traditional ReID technology is usually suitable for visible cameras with good lighting conditions, but its performance is severely limited under low-light conditions.The infrared camera is often used to collect infrared images of objects under low light conditions due to its outstanding night vision performance.Therefore, cross-modality object re-identification technology focuses on achieving uninterrupted object ReID across day and night from visible images to infrared images(VI-ReID),and vice versa.In recent years, VI-ReID technology has made significant progress.However, a comprehensive summary and in-depth analysis of existing models are still lacking.To this end, this paper conducts a
The exploration of performance luminescence near-infrared (NIR) material is crucial for rapidly developing NIR spectroscopic techniques. Herein, the NIR LaMg0.5Sn0.5O3:Cr3+ phosphor was synthesized ...by a high temperature solid-state method. And its luminescence performance were improved by In3+-Sc3+ substituting for Mg2+-Sn4+. The half-peak width can be expanded to 211 nm, the emission intensity can reach the seven times of that un-substitution, and the emission intensity at 423 K was maintained at 60 % of that at room temperature, moreover, the internal quantum efficiency can reach 54.2 %. On this basis, the phosphor converted light emitting diodes (pc-LEDs) were achieved by combining La(Mg1-xSn1-xInxScx)0.5O3:Cr3+ with blue LED, importantly, it can be applied to the biodetection and night vision lighting, which indicate its application value.
•The emission of La(Mg0.5Sn0.5In0.5Sc0.5)0.5O3: 0.003Cr3+ can red-shift to 821 nm by In3+-Sc3+ co-substitute for Mg2+-Sn4+.•The half-peak width can expand to 211 nm.•The emission intensity can be enhanced seven times of that before substitution.•The phosphor maintains an internal quantum efficiency of 54.2 %.
The near-infrared (NIR) light source has a huge potential for foodstuff analysis, biometric identification, physiological monitoring, and night vision technology with real-time and non-destructive ...advantages. Demand-led growth impels the exploration of novel NIR phosphors with broadband emission. Here we report a new kind of blue-light excitable NIR phosphor Mg7Ga2GeO12: xCr3+, in which the multi-site occupation of Cr3+ induces broadband NIR emission in the range of 600–1200 nm with a large full width at half maximum (FWHM) of ~190 nm and a NIR photoluminescence quantum yield (PLQY) of 12.06% at x = 0.02. The FWHM can be effectively adjusted from 101 to 226 nm via multisite occupancy preference of Cr3+ ions. The PL intensity remains ~50% and nearly 100% of the initial level after heated up to 400 K and immersed in hot water (100 °C) for 24 h, respectively, demonstrating good thermal stability and robust chemical stability. The broadband emission originated from multi-site PL centers of Cr3+ is discussed in detail by the temperature-dependent PL behaviors and PL decay lifetime. Finally, a broadband emission NIR-LED is fabricated, based on which a proof-of-concept application for night vision is demonstrated. This work not only provides a strategy for the design and developing of novel broadband NIR phosphors, but also indicates the potential for various advanced spectroscopy applications.
Broadband near‐infrared (NIR) phosphor‐converted (pc) LED is promising next‐generation tiny light source for smart and broadband NIR spectroscopy technology. However, NIR phosphors suffer from ...challenges in terms of low quantum efficiency and bandwidth. By selecting a host that has a big bandgap and weakening coupling effect among Cr3+, a novel LiGaP2O7:Cr3+ (LGAP:Cr3+) NIR phosphor that has a high external quantum efficiency (28.3%) is discovered. Under ≈450 nm excitation, LGAP:Cr3+ shows broad NIR emission from 700 to 1100 nm with a bandwidth of ≈170 nm. Importantly, the fabricated pcLED demonstrates bright broadband NIR light and an excellent performance in night vision. The results promise the use of the LGAP:Cr3+ phosphor for high‐performance broadband NIR LED that employs only one tiny blue LED chip.
Opening the bandgap of the LiGaP2O7 (LGAP) host and decreasing the coupling effect of Cr3+ to the host, LGAP:Cr3+ shows efficient and broadband near‐infrared (NIR) emission from 700 to 1100 nm. The fabricated NIR light‐emitting diode (LED) based on a blue chip and LGAP:Cr3+ phosphors shows bright NIR light peaked around 846 nm with a bandwidth of 168 nm.
Room‐temperature‐operating highly sensitive mid‐wavelength infrared (MWIR) photodetectors are utilized in a large number of important applications, including night vision, communications, and optical ...radar. Many previous studies have demonstrated uncooled MWIR photodetectors using 2D narrow‐bandgap semiconductors. To date, most of these works have utilized atomically thin flakes, simple van der Waals (vdW) heterostructures, or atomically thin p–n junctions as absorbers, which have difficulty in meeting the requirements for state‐of‐the‐art MWIR photodetectors with a blackbody response. Here, a fully depleted self‐aligned MoS2‐BP‐MoS2 vdW heterostructure sandwiched between two electrodes is reported. This new type of photodetector exhibits competitive performance, including a high blackbody peak photoresponsivity up to 0.77 A W−1 and low noise‐equivalent power of 2.0 × 10−14 W Hz−1/2, in the MWIR region. A peak specific detectivity of 8.61 × 1010 cm Hz1/2 W−1 under blackbody radiation is achieved at room temperature in the MWIR region. Importantly, the effective detection range of the device is twice that of state‐of‐the‐art MWIR photodetectors. Furthermore, the device presents an ultrafast response of ≈4 µs both in the visible and short‐wavelength infrared bands. These results provide an ideal platform for realizing broadband and highly sensitive room‐temperature MWIR photodetectors.
A novel metal‐mirror‐enhanced n–p–n van der Waals heterostructure is designed. The device exhibits excellent performance including high blackbody photoresponsivity up to 0.77 A W−1, high specific detectivity of 8.61 × 1010 cm Hz1/2 W−1 under blackbody radiation, and fast response speed of ≈4 µs.
Nowadays many patients are choosing EDOF or multifocal lenses for replacement of natural lens in cataract surgery. This can result in issues such as presence of dysphotopsias, namely halo and glare. ...In this work, we propose a new perimetry method to describe dysphotopsias in far-field region in a presence of bright, point-like light source. We constructed a custom device and designed measurement procedure for quantitative measurement of dysphotopias in the center of visual field and used it to examine patients with mild cataracts or implanted IOLs. Our approach may help in establishing an objective method to study and compare dysphotopsias.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Pancake lens has been widely used in virtual reality (VR) and mixed reality (MR) due to its compact form factor. However, using a half mirror (HM) to fold the optical path results in a tremendous ...optical loss. To enhance the optical efficiency while keeping a compact form factor, we present a new folded optical system incorporating a nonreciprocal polarization rotator. In our proof‐of‐concept experiment using a commercial Faraday rotator (FR), the theoretically predicted 100% efficiency is validated. Besides, the angular response of terbium gallium garnet (TGG) material is simulated for the first time and the results indicate that such an FR is relatively insensitive to the incident angle, which can dramatically enhance the contrast ratio of our pancake design. Finally, the potential application of such pancake optics for ultracompact near‐infrared (NIR) night vision goggles is also discussed.
We proposed a lossless and compact pancake optics using a nonreciprocal Faraday rotator as the imaging optics for VR displays. The effectiveness of the proposed system is validated by experiment. Such a novel design is expected to revolutionize the next‐generation VR displays and near infrared night vision google with lightweight, compact form factor, and low power consumption.
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•The lack of a functional SWS1 gene in owls is confirmed.•Owls also lack the enzyme required for red pigmentation L cone oil droplets.•The ocular media of owls transmit large amounts ...of ultraviolet.•Owls likely have trichromatic colour vision in daylight.•UV-transmittance of the ocular media make rod vision of owls more sensitive.
Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensitive opsin (LWS). Double cones (D) express LWS but do not contribute to colour vision. Each cone is equipped with an oil droplet, transparent in UV/V cones, but pigmented by carotenoids: galloxanthin in S, zeaxanthin in M, astaxanthin in L and a mixture in D cones. Owls (Strigiformes) are crepuscular or nocturnal birds with rod-dominated retinae and optical adaptations for high sensitivity. For eight species, the absence of functional SWS1 opsin has recently been documented, functional RH2 opsin was absent in three of these. Here we confirm the absence of SWS1 transcripts for the Long-eared owl (Asio otus) and demonstrate its absence for the Short-eared owl (Asio flammeus), Tawny owl (Strix aluco) and Boreal owl (Aegolius funereus). All four species had transcripts of RH2, albeit with low expression. All four species express all enzymes needed to produce galloxanthin, but lack CYP2J19 expression required to produce astaxanthin from dietary precursors. We also present ocular media transmittance of the Eurasian eagle owl (Bubo bubo) and Short-eared owl and predict spectral sensitivities of all photoreceptors of the Tawny owl. We conclude that owls, despite lacking UV/V cones, can detect UV light. This increases the sensitivity of their rod vision allowing them, for instance, to see UV-reflecting feathers as brighter signals at night.
Large area PMTs (LPMT) are widely used in neutrino experiments and cosmic ray detection. To meet the performance requirements for Jiangmen Underground Neutrino Observatory (JUNO), researchers at IHEP ...developed 20-inch MCP-PMTs which provide higher collection efficiency at a lower cost. 15k 20-inch PMTs produced by North Night Vision Technology Co., Ltd. (NNVT) has been delivered to Jiangmen and are to be installed as the central liquid scintillator detector of JUNO. Compared with prototype, though the collection efficiency (CE) and the quantum efficiency (QE) of the 15k MCP-PMTs get improved, the time performance gets worse. In this manuscript, the reasons for the deterioration of time resolution of the 15k MCP-PMTs are explored from several aspects. The optimized structure with great TTS of less than 5 ns is also introduced.
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