- 标题
- 摘要
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- 实验方案
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Single-pixel 3D reconstruction via a high-speed LED array
摘要： Three-dimensional reconstruction can be performed in many ways, among which photometric stereo is an established and intensively investigated method. In photometric stereo, geometric alignment or pixel-matching between two-dimensional images under different illuminations is crucial to the accuracy of three-dimensional reconstruction, and the dynamic of the scene makes the task difficult. In this work, we propose a single-pixel three-dimensional reconstructioning system utilizing structured illumination, which is implemented via a high-speed LED array. By performing 500kHz structured illumination and capturing the reflected light intensity with detectors at different spatical locations, two-dimensional images of different shadows with 64×64 pixel resolution are reconstructed at 122 frame per second. Three-dimensional profiles of the scene are further reconstructed using the surface gradients derived by photometric stereo algorithm, achieving a minimum accuracy of 0.50 mm. Chromatic three-dimensional imaging via an RGB LED array is also performed at 40 frame per second. The demonstrated system significantly improves the dynamic performance of the single-pixel three-dimensional reconstruction system, and offers potential solutions to many applications, such as fast three- dimensional inspection.
关键词： 3D reconstruction,LED array,single-pixel imaging
更新于2025-09-23 15:21:01
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Defect engineered mesoporous 2D graphitic carbon nitride nanosheet photocatalyst for Rhodamine B degradation under LED light illumination
摘要： In this work, a nitrogen vacancy induced 2D mesoporous graphitic carbon nitrogen (g-C3N4) nanosheet photocatalyst was successfully synthesized through a simple two step thermal treatment method. The morphology of the nanosheet photocatalyst and the presence of nitrogen vacancy was explored through a wide range of characterization techniques. The as prepared photocatalyst possess an improved visible light absorption efficiency as confirmed from the UV-Visible diffuse reflectance spectroscopy (DRS). Moreover, the improved charge carrier separation efficiency of the nitrogen vacant material was demonstrated from the photoluminescence spectrum. Most importantly, the photocatalyst exhibited an excellent photodegradation efficiency towards rhodamine B (RhB) dye under the illumination of an 18 W LED light. The vacancy induced nanosheets demonstrated a degradation co-efficient of 0.074 min-1 in RhB degradation, which is 9.25 fold higher than that of the bulk g-C3N4. The nanosheets further exhibited an enhanced degradation efficiency toward tetracycline antibiotic. Furthermore, the photocatalyst displayed an outstanding stability even after 5 cycles. A plausible photocatalytic mechanism has also been explained based on the results obtained from the radical scavenging experiments. This study would provide insight into the defect induction mechanism into the 2D g-C3N4 nanosheet and expected to help in rationally designing vacancy induced materials with cost effective application in various environmental fields.
关键词： nitrogen vacancy,LED light irradiation,rhodamine B,mesoporous,2D g-C3N4 nanosheet
更新于2025-09-23 15:21:01
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Design Guidelines on LED Costumes for Dance Performances
摘要： We present design guidelines on light emitting diode (LED) costumes for dance performances assuming repetitive use during concerts. We used LED costumes more than 120 times for large concerts of well-known artists at venues of approximately 50,000 capacity that were commercially successesful and we updated the LED costume design twice based on our experiences during these concerts. Through analyzing the position of broken LEDs and the types of breakage and the problems that occurred during actual performances, we devised 17 design guidelines on LED costumes for dance performances. Thanks to these design guidelines, the LEDs on the costume are more difficult to break and we can prepare for any contingencies that may occur during a performance. We fabricated an improved LED costume based on our design guidelines and conducted endurance tests involving dancing. Throughout the endurance tests, the LEDs did not break, and other factors that cause LED breakage were found. We participated in two exhibitions to conduct special LED dance performances.
关键词： dance performance,wearable computing,design guideline,costume,LED
更新于2025-09-23 15:21:01
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Deep clipping noise mitigation using ISTA with the specified observations for LED-based DCO-OFDM system
摘要： Deep clipping is beneficial for the optical orthogonal frequency division multiplexing (O-OFDM) system, since it can lower the peak-to-average power ratio, reduce the direct current requirement in light emitting diodes (LEDs), and relax the bit-resolution requirement in digital-to-analogue converters (DACs). However, it is accompanied by more signal distortions. In this study, a deep clipping noise mitigation scheme using iterative shrinkage/thresholding algorithm (ISTA) with three steps is proposed to improve bit error rate (BER) performance of the LED-based DCO-OFDM systems. In the first step, the estimated observation interference is eliminated from the received symbols to minimise the negative effect of channel noise. In the second step, two strategies are presented to generate the specified observations thus reduce the component of measurement noise in the whole observation vector. In the last step, combining the generalised cross validation and the estimation of observation interference, the appropriate regularisation parameter are calculated for ISTA to improve the robustness of the sparse recovery performance. They use simulations to show that the proposed scheme can correct the deep clipping noise with favourable reconstruction quality, which significantly improves the BER performance and therefore assist the LED non-linearity mitigation.
关键词： clipping noise mitigation,ISTA,BER performance,LED-based DCO-OFDM system,Deep clipping
更新于2025-09-23 15:21:01
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Coupled thermoa??electrical analysis of highly scaled GaN micro-LEDs with meshed hybrid conductors
摘要： Display technology with ultrafine pixels for near-eye application is a rapidly growing field due to the recent emergence of augmented/mixed reality. With the constant demand for high energy efficiency, long lifetime, and high luminosity, micro-LED displays based on compound semiconductors are promising candidates for such applications. However, miniaturizing LEDs results in significant drawbacks in terms of their quantum efficiency, current injection efficiency, and heat extraction. With relatively low device resistance compared to that of liquid crystals or organic LEDs, micro-LEDs are also more susceptible to the effects of parasitic resistance. In this study, gallium nitride based micro-LED displays with very small pixels (5 μm pixel, 10 μm pitch) are fabricated to study the thermal–electrical effect of meshed hybrid conductors on the optical emission efficiency. In situ thermographic imaging with I–V measurement confirms a significant trade-off among heat transfer, electrical conductivity, and light extraction efficiency. An increase of 37.9 % in the emission efficiency (2,540 PPI, 5 μm pixels, 1 mm2 display, at 49.2 ℃) is achieved by optimizing the thermal and electrical conduction paths. This study experimentally confirms the importance of thermal management and multi-physics analysis in designing ultra-small-pixel micro-LEDs with high energy efficiency.
关键词： hybrid transparent conductor,Thermo–electrical analysis,gallium nitride,micro-LED
更新于2025-09-23 15:21:01
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[IEEE 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Pitesti, Romania (2019.6.27-2019.6.29)] 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Design of an LED-based solar spectrum simulator for porphyrin dye-sensitized solar cell characterization
摘要： This paper presents the design considerations for a special solar spectrum simulator, based on LED technology, specifically conceived for the characterization of porphyrin-based dye-sensitized solar cells.
关键词： solar spectrum,photovoltaics,solar simulator,DSSC,LED
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th Global Conference on Consumer Electronics (GCCE) - Osaka, Japan (2019.10.15-2019.10.18)] 2019 IEEE 8th Global Conference on Consumer Electronics (GCCE) - An AC-Powered Smart LED Bulb for 3D Indoor Localization Using VLC
摘要： This paper demonstrates a smart LED bulb for indoor localization based on visible light communication (VLC) techniques, which is directly supplied with an AC power. It consists of two building blocks: a power management block and a control block. The power management block generates (30V and 5V) DC power supply for the LEDs and the control block, respectively, from the AC power. The control block modulates the light intensity of the LEDs via an NMOS switch to transmit pre-defined localization data patterns. Finally, the transmitted VLC signal is detected with a mobile phone camera.
关键词： Smart LED Bulb,AC Power Supply,Indoor Localization,VLC
更新于2025-09-23 15:21:01
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Plant Growth and Photosynthetic Characteristics of Soybean Seedlings Under Different LED Lighting Quality Conditions
摘要： Light-emitting diodes (LEDs) have recently been widely used as light sources for the cultivation of plants in controlled environments. However, before LEDs can be used as the sole light source, it is imperative that soybean (Glycine max) response to light quality be well characterized. The objective of the present work was to investigate how soybean seedlings respond to different blue (B) and red (R) photon flux ratios (PFR) using LEDs. Light treatments were comprised of 170 ± 5 μmol m?2 s?1 photosynthetic photon flux density with B:R ratios of 0B:100R%, 10B:90R%, 25B:75R%, 50B:50R%, 80B:20R%, 90B:10R%, and 100B:0R%. Our results suggest that with the increase in B PFR from 0 to 90%, both plant height and specific leaf area inclined to decline while stem diameter gradually increased. The plants exposed to 80B:20R% showed unexpectedly greater total root length, root surface area, root volume, number of root tip, plant dry mass, leaf dry mass, root dry mass, leaf mass fraction and root mass fraction than plants exposed to all other treatments. Plants grown with 0B:100R% had the highest content of chlorophyll b (Chl b) and content of total chlorophyll [Chl (a + b)] but possessed the lowest ratio of the content of chlorophyll a to the content of chlorophyll b (Chl a/b). Plants grown with R alone also showed the lowest chlorophyll fluorescent parameters. The light-saturated CO2 assimilation rate (Asat) and the light-saturated stomatal conductance (gssat) for 0B:100R% were, respectively, 64.85% and 203.23% lower than those for 80B:20R%. However, plants grown with sole R accumulated higher soluble sugar and starch content during the daytime. Collectively, our results suggest that compared to R- or B-LED alone, an appropriate combination of R and B promotes plant growth and photosynthetic performance for soybean.
关键词： Soybean,Plant growth,Light quality,Photosynthetic characteristics,LED
更新于2025-09-23 15:21:01
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[IEEE 2019 International Conference on Information and Communication Technology Convergence (ICTC) - Jeju Island, Korea (South) (2019.10.16-2019.10.18)] 2019 International Conference on Information and Communication Technology Convergence (ICTC) - A simple LED panel dection algoritum for Optical Camera Communication systems
摘要： In optical camera communication (OCC), LED panels are used to transmit visible light signal which will be received by cameras. The transmitted data is obtained through processing the captured images of LED panels. The first step in this process is to determine where the LED panels are in the image. Existing object detection algorithms are not originally designed for LED detection and thus is not effective for this task. In this study, based on distinct characteristics of LED, a simple and effective LED panel detection algorithm is proposed. The performance of the proposed algorithm is verified through simulations.
关键词： communication,simulation,optical,camera,LED
更新于2025-09-23 15:21:01
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Volumetric light-shaping polymer-dispersed liquid crystal films for mini-LED backlights
摘要： Volumetric light-shaping polymer-dispersed liquid crystal (PDLC) films for mini-LED backlit liquid crystal displays (LCDs) are proposed and experimentally demonstrated. With proper material engineering and good vertical alignment of liquid crystals, passive PDLC films with angle-selective scattering properties can be achieved. Such films only respond to angles rather than spatial locations. By directly adhering the PDLC films onto a LED, angular intensity distribution of light can be tailored from Lambertian-like to batwing-like. Further simulation shows that by engineering the angular distribution, a fewer number of LEDs or equivalently a shorter light-spreading distance should be required to maintain good uniformity. Such a PDLC film would find widespread applications in emerging mini-LED backlit LCDs and shed light on designing other light-shaping films in the future.
关键词： Polymer-dispersed liquid crystals,volumetric diffusers,angle-dependent scattering,mini-LED backlights
更新于2025-09-23 15:21:01