Search

In this paper, we present a novel vision-based approach for 3D reconstruction using a single 360° camera, aiming to offer a simplified and accessible solution for various consumer-oriented applications. Consumer-grade 360° cameras have gained significant popularity due to their affordability and ease of use. However, traditional methods for 3D reconstruction often require complex setups with multiple cameras or expensive hardware such as Light Detection and Ranging (LiDAR). Our approach addresses the challenges associated with 360° cameras by converting the distorted Equirectangular Projection (ERP) into four perspective views, allowing compatibility with deep learning models trained on undistorted perspective images. We leverage Visual Simultaneous Localization and Mapping (VSLAM) techniques for camera pose estimation and employ a standard 3D reconstruction pipeline for generating detailed 3D mesh representations of the indoor environment. Through experimental evaluation, we compare the performance of 360° cameras with traditional perspective cameras in 3D reconstruction and analyze the accuracy and performance of our vision-based approach. Our findings demonstrate the potential of using 360° cameras for constructing high-quality models and facilitating efficient data collection for 3D reconstructions, opening up new possibilities for various consumer-oriented applications in multiple fields.

Recent technological advances in next-generation sequencing (NGS) technologies have dramatically reduced the cost of DNA sequencing, allowing species with large and complex genomes to be sequenced. Although bread wheat (Triticum aestivum L.) is one of the world's most important food crops, efficient exploitation of molecular marker-assisted breeding approaches has lagged behind that achieved in other crop species, due to its large polyploid genome. However, an international public-private effort spanning 9 years reported over 65% draft genome of bread wheat in 2014, and finally, after more than a decade culminated in the release of a gold-standard, fully annotated reference wheat-genome assembly in 2018. Shortly thereafter, in 2020, the genome of assemblies of additional 15 global wheat accessions was released. As a result, wheat has now entered into the pan-genomic era, where basic resources can be efficiently exploited. Wheat genotyping with a few hundred markers has been replaced by genotyping arrays, capable of characterizing hundreds of wheat lines, using thousands of markers, providing fast, relatively inexpensive, and reliable data for exploitation in wheat breeding. These advances have opened up new opportunities for marker-assisted selection (MAS) and genomic selection (GS) in wheat. Herein, we review the advances and perspectives in wheat genetics and genomics, with a focus on key traits, including grain yield, yield-related traits, end-use quality, and resistance to biotic and abiotic stresses. We also focus on reported candidate genes cloned and linked to traits of interest. Furthermore, we report on the improvement in the aforementioned quantitative traits, through the use of (i) clustered regularly interspaced short-palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene-editing and (ii) positional cloning methods, and of genomic selection. Finally, we examine the utilization of genomics for the next-generation wheat breeding, provi

Pedestrian dead reckoning (PDR) is an inertial navigation system that relies on smartphone sensors for estimating a pedestrian’s step movements. However, such systems suffer from poor accuracy due to the drift and inherent noise in sensor readings. In addition, step size variation among pedestrians and device heterogeneity pose further challenges for building a scalable PDR system that can provide uniform performance across various devices and a diverse range of users. Visible light positioning (VLP), which uses LED lights with visible light communication (VLC) capability to provide high-accuracy localization, can achieve precision of a few cm. However, VLP systems suffer from practical limitations due to occasional line-of-sight blockage and the sparse density of lighting in large-scale indoor venues. In this work, we propose a light-assisted dead reckoning (LiDR) system, which aims to address the problems of both VLP and PDR. It uses LED lighting as high-accuracy location landmarks to provide regular calibration for the PDR and estimates the individual pedestrians’ step size for increased accuracy. In addition, a light-shape-based heading angle correction algorithm is proposed to reduce the heading angle error and further improve the accuracy. The system is implemented as an Android-based navigation application, with a digital map and cloud-based backend storage for location, device and user-specific parameters. The real-time performance of the system is evaluated in a 450 m2 lab and on a 150 m walking track. The experimental results demonstrate that, with a maximum light spacing of 15 m, an overall average accuracy of < 0.7 m can be achieved for the whole system. IEEE

This study examines the nexus between green transformational leadership (GTL) and environmental performance (EP), considering the mediating role of green human resource management (GHRM) and green innovation (GI). Besides, we also find the moderating effects of environmental values (EV) between GTL and EP. This study collected data from 110 respondents using a survey questionnaire from small and medium enterprises and employed structural equation modeling. The findings confirm a positive and significant effect of GTL on EP. Furthermore, mediation analysis confirms that GHRM and GI positively mediate between GTL and EP. Moreover, it is also confirmed from structural equation modelling that EV play moderating role between GTL and EP. These results offer valuable recommendations for all stakeholders.

Recent technological advances in next-generation sequencing (NGS) technologies have dramatically reduced the cost of DNA sequencing, allowing species with large and complex genomes to be sequenced. Although bread wheat (Triticum aestivum L.) is one of the world's most important food crops, efficient exploitation of molecular marker-assisted breeding approaches has lagged behind that achieved in other crop species, due to its large polyploid genome. However, an international public-private effort spanning 9 years reported over 65% draft genome of bread wheat in 2014, and finally, after more than a decade culminated in the release of a gold-standard, fully annotated reference wheat-genome assembly in 2018. Shortly thereafter, in 2020, the genome of assemblies of additional 15 global wheat accessions was released. As a result, wheat has now entered into the pan-genomic era, where basic resources can be efficiently exploited. Wheat genotyping with a few hundred markers has been replaced by genotyping arrays, capable of characterizing hundreds of wheat lines, using thousands of markers, providing fast, relatively inexpensive, and reliable data for exploitation in wheat breeding. These advances have opened up new opportunities for marker-assisted selection (MAS) and genomic selection (GS) in wheat. Herein, we review the advances and perspectives in wheat genetics and genomics, with a focus on key traits, including grain yield, yield-related traits, end-use quality, and resistance to biotic and abiotic stresses. We also focus on reported candidate genes cloned and linked to traits of interest. Furthermore, we report on the improvement in the aforementioned quantitative traits, through the use of (i) clustered regularly interspaced short-palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene-editing and (ii) positional cloning methods, and of genomic selection. Finally, we examine the utilization of genomics for the next-generation wheat breeding, provi

Financial instability refers to the situation when financial system faces some disturbances and volatility. There are some important factors that can have a significant influence on the stability or instability of the financial sector. The main objective of this study is to examine the impact of financial sector development, financial liberalization, and GDP growth rate on financial instability. Using data from 53 countries from 2000 to 2016 and employing a battery of estimation techniques consisting of fixed effect, random effect, dynamic panel, and system GMM, the study finds that financial development and financial liberalization accentuate financial instability. The study also finds that economic growth dampens it. Furthermore, the relationship is robust to a variety of controls like monetary independence index, exchange rate stability, law and order, and government expenditure. The policy implication is straightforward that financial development and financial liberalization demand a caution.

Smart home systems (SHSs) are a modern lifestyle trend, changing daily lives in the most intuitive way. To connect and operate various smart devices under one system, an accurate, convenient, and secure control method is of utmost significance. Nowadays, most smart home control systems are based on radio-frequency (RF) technologies such as Bluetooth, Wi-Fi, and Zigbee. They tend to suffer from poor location accuracy in high-density environments due to the interference and noise in RF signals as well as their penetration through walls, leading to security vulnerabilities and low-precision control. To address these issues, this paper presents a smart home control system based on visible light communication (VLC), with enhanced security and accurate localization for precise and convenient control. The system includes an AC lightbulb, a smartphone running the position and control applications, and a cloud server with location-based access and a database of smart home devices. The design of the AC lightbulb integrates VLC and Bluetooth connectivity in a standard form factor for easy installation and plug-n-play capability. A smartphone camera-based 3D indoor positioning and orientation algorithm that allows precise control by pointing the smartphone the device is also presented. We demonstrate the feasibility of this system through prototype implementation and experimental verification. © 2022 by the authors.

An indoor positioning algorithm is presented that uses a single rectangular visible light communication (VLC)-modulated LED as a transmitter and the CMOS image sensor of a smartphone camera as a receiver. The real-world location of the LED is transmitted as a VLC signal that is decoded by the smartphone using optical camera communication (OCC). Then the location of the smartphone is calculated by finding the camera pose using the perspective-n-point algorithm on the real-world coordinates and corresponding image coordinates of the LED. The algorithm is experimentally evaluated as a real-time application running on a smartphone. The experimental results show that the algorithm can achieve an average 3D positioning error of less than 5 cm for an arbitrarily tilted smartphone.

With the rapid development of robotics and in-depth research of automatic navigation technology, mobile robots have been applied in a variety of fields. Map construction is one of the core research focuses of mobile robot development. In this paper, we propose an autonomous map calibration method using visible light positioning (VLP) landmarks and Simultaneous Localization and Mapping (SLAM). A layout map of the environment to be perceived is calibrated by a robot tracking at least two landmarks mounted in the venue. At the same time, the robot’s position on the occupancy grid map generated by SLAM is recorded. The two sequences of positions are synchronized by their time stamps and the occupancy grid map is saved as a sensor map. A map transformation method is then performed to align the orientation of the two maps and to calibrate the scale of the layout map to agree with that of the sensor map. After the calibration, the semantic information on the layout map remains and the accuracy is improved. Experiments are performed in the robot operating system (ROS) to verify the proposed map calibration method. We evaluate the performance on two layout maps: one with high accuracy and the other with rough accuracy of the structures and scale. The results show that the navigation accuracy is improved by 24.6 cm on the high-accuracy map and 22.6 cm on the rough-accuracy map, respectively. © 2022 by the authors.

Accurate indoor positioning is critical in the field of location-based services and robotics. Visible light positioning (VLP) technology is a promising technique as it can provide high accuracy positioning based on the existing lighting infrastructure. However, it is difficult to meet the requirement of multiple LED anchors in range for successful and accurate positioning. In this paper, we proposed a loosely-coupled VLP-inertial fusion method for VLP, with an inertial measurement unit (IMU) and rolling shutter camera, to improve positioning robustness under LED shortage/outage. The efficacy of the proposed VLP scheme as well as the robustness under LED outage, handover situation and background light interference, are verified by real-world experiments1. The results show that our proposed scheme can provide an average accuracy of 2.1 cm (stationary localization) and the average computational time in low-cost embedded platforms is around 33 ms. IEEE

Indoor visible light positioning (VLP) systems can be directly integrated with existing lighting infrastructure and achieve high-accuracy positioning when using CMOS image sensors as receivers. Due to cameras’ limited field of view (FOV), VLP systems based on multiple light emitting diodes (LEDs) require lamps to be arranged with high density, which is not practical in realistic scenarios. Additionally, smartphones held in the human hand may rotate about the x-, y- or z-axis. This paper proposes a tilted receiver camera correction method for indoor VLP systems to eliminate the additional positioning errors caused by rotation. Furthermore, the proposed method can suppress the positioning errors when part of the LED light is blocked, and can therefore enhance the robustness of the VLP system. The experimental results show that the proposed VLP method can achieve average positioning error within 7 cm when more than 40% of the LED image is captured, and can achieve average positioning error of 3.9 cm when more than 90% of the LED image is captured. IEEE

Recent technological advances in next-generation sequencing (NGS) technologies have dramatically reduced the cost of DNA sequencing, allowing species with large and complex genomes to be sequenced. Although bread wheat (Triticum aestivum L.) is one of the world’s most important food crops, efficient exploitation of molecular marker-assisted breeding approaches has lagged behind that achieved in other crop species, due to its large polyploid genome. However, an international public–private effort spanning 9 years reported over 65% draft genome of bread wheat in 2014, and finally, after more than a decade culminated in the release of a gold-standard, fully annotated reference wheat-genome assembly in 2018. Shortly thereafter, in 2020, the genome of assemblies of additional 15 global wheat accessions was released. As a result, wheat has now entered into the pan-genomic era, where basic resources can be efficiently exploited. Wheat genotyping with a few hundred markers has been replaced by genotyping arrays, capable of characterizing hundreds of wheat lines, using thousands of markers, providing fast, relatively inexpensive, and reliable data for exploitation in wheat breeding. These advances have opened up new opportunities for marker-assisted selection (MAS) and genomic selection (GS) in wheat. Herein, we review the advances and perspectives in wheat genetics and genomics, with a focus on key traits, including grain yield, yield-related traits, end-use quality, and resistance to biotic and abiotic stresses. We also focus on reported candidate genes cloned and linked to traits of interest. Furthermore, we report on the improvement in the aforementioned quantitative traits, through the use of (i) clustered regularly interspaced short-palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated gene-editing and (ii) positional cloning methods, and of genomic selection. Finally, we examine the utilization of genomics for the next-generation wheat breeding, provi

A high precision visible light communication (VLC)-based mobile robot positioning demonstration is proposed1. Based on our built experiment platform, the positioning accuracy is within 2cm. © 2021 OSA.

This paper presents critical amendments to the subject paper. The names of the authors are included here, who should have been credited in the subject paper for their contribution in designing the hardware, facilitating the system development, and constructing the testbed.

Indoor visible light positioning (VLP) systems can be directly integrated with existing lighting infrastructure and achieve high-accuracy positioning when using CMOS image sensors as receivers. Due to cameras’ limited field of view (FOV), VLP systems based on multiple light emitting diodes (LEDs) require lamps to be arranged with high density, which is not practical in realistic scenarios. Additionally, smartphones held in the human hand may rotate about the x-, y- or z-axis. This paper proposes a tilted receiver camera correction method for indoor VLP systems to eliminate the additional positioning errors caused by rotation. Furthermore, the proposed method can suppress the positioning errors when part of the LED light is blocked, and can therefore enhance the robustness of the VLP system. The experimental results show that the proposed VLP method can achieve average positioning error within 7 cm when more than 40% of the LED image is captured, and can achieve average positioning error of 3.9 cm when more than 90% of the LED image is captured. IEEE

Accurate indoor positioning is critical in the field of location-based services and robotics. Visible light positioning (VLP) technology is a promising technique as it can provide high accuracy positioning based on the existing lighting infrastructure. However, it is difficult to meet the requirement of multiple LED anchors in range for successful and accurate positioning. In this paper, we proposed a loosely-coupled VLP-inertial fusion method for VLP, with an inertial measurement unit (IMU) and rolling shutter camera, to improve positioning robustness under LED shortage/outage. The efficacy of the proposed VLP scheme as well as the robustness under LED outage, handover situation and background light interference, are verified by real-world experiments1. The results show that our proposed scheme can provide an average accuracy of 2.1 cm (stationary localization) and the average computational time in low-cost embedded platforms is around 33 ms. IEEE

This paper demonstrates a smart high-power LED lightbulb equipped with visible light communication (VLC) functionality for a target smart-home system (SHS). We present both a theoretical model and a hardware prototype to verify its ability to control domestic devices. The lightbulb consumes 10.3 W electric power and reaches a communication distance of 3 m. It serves as a beacon in the SHS, furnishing location data and information about the information appliances (IAs) that can be controlled in a particular room. Managing the IAs in the SHS is performed through Bluetooth via a preinstalled smartphone app.

Economic growth, although being a major quest of all the economies, is not an automatic phenomenon. Among its determinants, structural change in the form of reallocation of labour from low to high productivity sectors is of crucial importance. In view of the remarkable growth performance and unprecedented structural change of Asia in the last couple of decades, this paper empirically investigated the case of 20 selected Asian countries. By employing the data spanning from 1991 to 2018, the study shows three main results. First, by employing Shift Share Analysis framework, it reaffirms the findings of previous literature that structural change contributes to the aggregate productivity growth. Second, by utilizing Generalized Methods of Moments technique, the results find it to be an important booster of growth. Third, the results are reliable and consistent with alternative measures of structural change like Norm of Absolute Values and Modified Lilien Index. Taken together, these findings suggest that the governments in Asia (other regions like Africa and Latin America may alike) must chalk out policies for structural change promotion.

The study was design to evaluate the effect of water regimes on overall performance of wheat and optimum need of water. Wheat was tested under 2, 3 and 4 numbers of irrigations named as I1, I2 and I3 respectively. Treatments were arranged in randomized complete block design (RCBD) with factorial arrangement. Sowing was started in November 2018 by automatic drill in Rabi. Observations on growth and yield parameters of wheat were recorded by following standard procedures. The data collected were analyzed statistically by applying least significant difference test (LSD) at 5% probability level for comparison among treatment’s means. The I3 had significantly (P<0.05) high leaf area index, plant height, spike length (cm), no. of spikelets/spike, biological yield of wheat, grain yield (t ha-1), straw yield of (t ha-1), harvest index (%) significantly While the days to booting, tillers (m-2), no. of grains/spike, grain weight/spike, weight of 1000 grains had not significant differences. It was concluded that the I3 with 4 irrigations had a potentially high yield, performance and economically beneficial.

This paper presents a smart lighting solution using Bluetooth and visible light communication (VLC) to enable smart lighting control and location-based services. Integrating VLC into smart lights can allow unique line-of-sight-based directional control using a smartphone camera. When combined with Bluetooth, VLC can facilitate smart lighting installations in large commercial and industrial venues. VLC and Bluetooth can complement each other to provide accurate location inside venues to support a wide range of consumer and industrial location-aware applications. © 2019 IEEE.

A universal visible light communication (VLC) modulator design is presented in this paper. The modulator is used to retrofit LED lighting and signage to enable VLC by connecting it between the LED driver output and LED lighting input. The modulator can work with both major types of LED drivers, i.e., constant current type and constant voltage type, and can support a wide input voltage range. Experiments are conducted to verify the modulation function and its impact on the light intensity of the luminaire. © 2019 IEEE.

A wireless control system for visible light communication (VLC) is presented in this paper. It is equipped with Bluetooth Low Energy (BLE) SoC to support iBeacon and the VLC data/frequency can be easily configured by smartphone. This combo beacon/lighting/VLC functionality helps to cut the cost of beacon deployment and increase the indoor localization accuracy. © 2019 IEEE.

This paper presents a smart micro-light-emitting-diode (mu LED) display system employing visible light communication (VLC) as the near-field communication technology for portable devices equipped with mu LED displays. In the transmitter, a VLC modulator is integrated into a 400 x 240 gallium nitride (GaN) mu LED display with a pixel size of 30 x 30 mu m(2) to enable simultaneous display and VLC functions. In the receiver, two different configurations are implemented, including a photodiode (PD)-based and a smartphone camera-based receiver. The smart mu LED display-VLC system with the two different receivers is characterized by varying the distance and the angle between the transmitter and the receiver. Experimental results show that the PD-based system can achieve a bit rate of 2 Mb/s and a maximum overall data rate of 550 kb/s beyond 10 cm, but it is sensitive to angular misalignment. In contrast, the camera-based system is more suitable for the transmission of short pieces of information at a bit rate of 16.6 kb/s, and the maximum overall data rate is 5 kb/s at a distance of 5 cm (and 2.5 kb/s when the distance is extended to 10 cm). Moreover, the camera-based system is less sensitive to angular misalignment.

This paper focuses on the design and implementation of an automatic synchronizing and protection relay to automate the synchronization process of a Distributed Energy Resource (DER) to the Main Grid. The proposed design utilize a cost-effective data acquisition using arduino in combination with LabVIEW software to implement the multi-purpose synchronizing relay. The proposed synchronizing relay is capable of synchronizing a Distributed Generator (DG) to the power grid from black-start and fulfills the requirements imposed by the utility. The synchronizing relay is implemented through voltage and frequency control of an actual lab-scale synchronous generator. In the synchronization process, frequency synchronization is done using speed control of the stepper motor as prime mover and voltage synchronization is accomplished using Excitation Control module through Power-Hardware-in-the-Loop (PHIL) simulation. In grid-connected mode, active and reactive power controls and protection schemes for the synchronous generator have also been implemented. The proposed multi-function relay has been deployed and tested on a lab-scale test bed to validate the proposed design and functionality., Comment: 6 pages, 14 figures, submitted in IEEE International Symposium on Recent Advances in Electrical Engineering

The LED backlights of LCD displays are modulated to broadcast relevant information synchronized to the screen content in each frame using visible light communication (VLC) or Li-Fi. The signal is then captured and decoded by a smartphone camera to establish an optical camera communication (OCC) link. This work presents a Li-Fi based QR code (LiQR) backlight modulator that is embedded in a LCD display to enable IoT applications including location and content based information broadcasting. © 2018 OSJ

The first real-time micro-LED (µLED) display with simultaneous visible light communication (VLC) function for text message broadcast based on a 400×240 blue µLED array is presented, demonstrating the great potential of enabling various displays using VLC technologies for futuristic IoT applications. Transmitted messages are detected and shown on an LCD.

Under-sampled camera communication (CamCom) systems realized using fast shutter speeds limit the communication channel length and impose restrictions on the minimum signal-to-noise ratio (SNR) requirement of LED based transmitters. In this paper, we present an empirical model to estimate the effective channel length of a CamCom system. Based upon the model, a transceiver methodology is proposed and demonstrated to support low-SNR transmitters, thereby increasing the effective communication distance of an under-sampled CamCom link. Moreover, an adaptive threshold decoding technique is presented to make the system robust against the variable frame rate phenomenon. The proposed methodology can be utilized to increase the communication distance of under-sampled CamCom links for infrastructure-to-vehicle communication employing low-SNR transmitters.

The first real-time micro-LED (µLED) display with simultaneous visible light communication (VLC) function for text message broadcast based on a 400×240 blue µLED array is presented, demonstrating the great potential of enabling various displays using VLC technologies for futuristic IoT applications. Transmitted messages are detected and shown on an LCD.

This paper presents an energy-efficient visible light communication (VLC) receiver SoC that utilizes ambient light rejection and post-equalization techniques for emerging LiFi applications. Based on ordinary phosphorescent white LEDs, a 24-Mb/s IEEE 802.15.7-compliant LiFi link is demonstrated over 1.6 m with a BER below 10−9. © 2017 IEEE.

An adaptive threshold decoding algorithm is proposed for recovering visible light communication signals transmitted by a LED-based display. The measured BER of data received from a 4-frame/s micro-LED display is improved from 6.9×10−2 to 4.4×10−4 using the proposed algorithm compared to conventional constant threshold scheme. © 2017 IEEE.

This paper presents an IEEE 802.15.7 Physical Layer I (PHY-I) standard compliant visible light communication (VLC) transmitter system-on-a-chip (SoC), enabling the use of ordinary white LED lights as beacons or broadcasters for location-based applications. The mixed-signal SoC integrates a baseband digital signal processing (DSP) unit, a VLC modulator, and a switching boost LED driver with an on-chip power MOSFET. The DSP unit supports various coding schemes as well as both the on-off keying (OOK) modulation and the variable pulse-position modulation specified in the aforementioned standard. The boost LED driver is designed to power a matrix of 4 × 5 LEDs using Li-ion batteries for portable applications. The SoC simultaneously supports VLC and LED illumination with nine dimming levels. Implemented in a 0.35-μm CMOS process with 20-V devices, the SoC achieves a measured VLC data rate of up to 266 kb/s at a package error rate (PER) <; 10% using a 211 -1 PRBS (pseudo random binary sequence) input. The communication distance measured is more than 2 m using no optical lens with the link efficiency of 5 nJ/bit. From an input at 3-5 V, the boost converter generates an output at 6-20 V with a 92% peak efficiency and an 8-W rating.

This paper presents the design and characterization of the first active matrix light-emitting diode (AMLED) microdisplay with an embedded visible light communication (VLC) transmitter, enabling LED digital signage for location-based applications such as information broadcasters and indoor positioning beacons. The driver system-on-a-chip (SoC) integrates four identical macro-cells, each containing a pixel driver array, a row driver, a column driver and a first-in first-out (FIFO) memory, to drive a wide quarter-VGA (WQVGA) display featuring 400×240 blue micro-LED (μLED) pixels fabricated on a single gallium nitride (GaN) substrate. The size of each μLED pixel is 30×30 μm2. At the system level, pulse-width modulation (PWM) superimposed with on-off keying (OOK) modulation is proposed to accomplish grayscale control for display and simultaneously transmit VLC signal by modulating the μLED array. At the circuit level, a pixel driver cell composed of three transistors and one capacitor (3T1C) with a novel VLC function is employed to implement the control scheme. Flip-Chip bonding is adopted to establish connections between the WQVGA microdisplay and the AMLED driver SoC. Implemented in a 0.5-μm 2P3M CMOS process, the driver SoC enables a high-resolution microdisplay module to achieve 4-bit grayscale at a 100-Hz frame rate, while supporting 1.25-Mb/s VLC for a bit error rate (BER) <10-5 up to 25-cm distance without a lens. When using optical lenses, the VLC distance is extended to >500 cm.

This paper presents the first active matrix LED (AMLED) microdisplay driver with built-in visible light communication (VLC) transmitter. The wide quarter-VGA (WQVGA) display features 400×240 pixels of 30×30 μm2 micro-LEDs (μLED) on a single GaN IC flip-chip bonded to the proposed driver SoC. Pulse-width modulation (PWM) superimposed with on-off keying (OOK) modulation are employed for controlling the display grayscale and modulating the pixels with VLC data simultaneously. Implemented in 0.5-μm CMOS, the SoC enables a microdisplay module featuring 4-bit grayscale at 100-Hz frame rate while achieving 1.25-Mb/s lensless VLC up to 25 cm.

This paper presents the first IEEE 802.15.7 PHY-I standard compliant visible light communication (VLC) transmitter and LED driver SoC for location-based applications using standard white LED lights as beacons or broadcasters. Implemented in a 0.35μm CMOS process with 20-V high-voltage device, the mixed-signal SoC integrates a baseband DSP unit, a VLC modulator, and a switching boost converter with an on-chip power MOSFET. Designed to drive an array of up to 4×5 LEDs using batteries, the boost converter generates an output at 6-20 V from an input at 3-5V with a 92% peak efficiency and an 8-W rating. Measured VLC data rate up to 266 kb/s with 211-1 PRBS inputs is achieved at a PER of <;10% and transmission efficiency of 5 nJ/bit. The LED driver can simultaneously support nine dimming levels and VLC.

This paper presents two advanced visible light communication (VLC) modulator system-on-chips (SoCs). The first is an IEEE 802.15.7 PHY-I standard compliant VLC transmitter. The second is an active matrix LED microdisplay with embedded VLC function. © 2015 IEEE.

Using LED lights for visible light communication (VLC) has received a great deal of interest because of a wide range of new applications such as location-based wireless broadcasting through LED lightings, signs with LED backlights and digital LED displays, as well as indoor positioning and navigation utilizing LED lights as location beacons. Recently, a number of VLC systems have been reported with focus ranging from functionality demonstration to using various modulation schemes for data rate improvement. However, systematic analysis and design methodologies for implementing a VLC system fulfilling certain specifications have been largely overlooked. This work presents, for the first time, a systematic approach to VLC transceiver design based on an analytical study of system design considerations and optical wireless link budget analysis. To obtain the signal-to-noise ratio (SNR) at the receiver, the received signal power is predicted by modeling the transmitted optical power and the channel path loss while the input-referred noise is estimated by characterizing the noise contribution from each of the receiver building blocks. To validate the proposed approach, a VLC transceiver using discrete components has been designed, achieving a data rate of 2.5 Mb/s and a communication distance of ~2m. Furthermore, another VLC system using a fully integrated CMOS transmitter SoC compliant with IEEE 802.15.7 standard is implemented. The SoC integrating a DC-DC power converter, a VLC modulator and a baseband unit measures a record energy efficiency of ~5nJ/bit.

This paper presents the complete link budget analysis of a VLC system. By calculating the transmitter's emitted power, the channel path loss and the receiver's input referred noise, the system SNR and BER performance are derived. Furthermore, a VLC transceiver system is implemented with the analog front-end using discrete components while the baseband in FPGA, and the experimental results demonstrate that the measured BER agrees well with the calculation. © 2015 IEEE.

This paper presents, for the first time, a systematic approach to visible light communication (VLC) transceiver design based on an analytical optical wireless link budget study. To obtain the signal-to-noise ratio at the receiver, the received signal power is predicted by modeling the transmitted optical power and the channel path loss, while the input-referred noise is estimated by characterizing the noise contribution from each of the receiver building blocks. Based on the targeted bit error rate (BER) and communication distance, a VLC transceiver using discrete components and a fully integrated CMOS VLC transmitter compliant with the IEEE 802.15.7 Standard have been designed and tested. Experimental results show that the measured BER agrees well with the proposed model for both the systems, validating our design approach and the link budget analysis.

This paper presents the complete link budget analysis of a VLC system. By calculating the transmitter's emitted power, the channel path loss and the receiver's input referred noise, the system SNR and BER performance are derived. Furthermore, a VLC transceiver system is implemented with the analog front-end using discrete components while the baseband in FPGA, and the experimental results demonstrate that the measured BER agrees well with the calculation.

Indoor localization is the fundamental capability for indoor service robots and indoor applications on mobile devices. To realize that, the cost of sensors is of great concern. In order to decode the signal carried out by the LED beacons, we propose two reliable solutions using common sensors available on consumer electronic devices. Firstly, we introduce a dedicated analog sensor, which can be directly connected to the microphone input of a computer or a smart phone. It decodes both the signal pattern and signal strength of a beacon. Secondly, we utilize rolling-shutter cameras to decode the signal pattern, providing potential solutions to the localization of hand-held devices with cameras. In contrast to existing widely-applied indoor localization approaches, like vision-based and laser-based methods, our approach reveals its advantages as low-cost, globally consistent and it retains the potential applications using Visible Light Communication(VLC). We also study the characteristics of the proposed solutions under typical indoor conditions by experiments.

This paper presents the design and implementation of a VLC (visible light communication) transceiver complying with the Type-I physical layer (PHY-I) specified in IEEE 802.15.7 Standard. Both the system architectures and the building blocks are described in detail. The design is implemented by Verilog-HDL and verified on Xilinx Virtex-5 Field-Programmable Gate Arrays (FPGA). Layout implementation using ASIC development tools is also provided for the transmitter design. The system is targeted at information broadcasting with data rates from 11.67 kb/s to 266.6 kb/s. Measurement result proves that the system can achieve a bit error rate (BER) of 10-6 when the received illuminance is 18 lx. © 2014 IEEE.

Indoor localization is the fundamental capability for indoor service robots and indoor applications on mobile devices. To realize that, the cost of sensors is of great concern. In order to decode the signal carried out by the LED beacons, we propose two reliable solutions using common sensors available on consumer electronic devices. Firstly, we introduce a dedicated analog sensor, which can be directly connected to the microphone input of a computer or a smart phone. It decodes both the signal pattern and signal strength of a beacon. Secondly, we utilize rolling-shutter cameras to decode the signal pattern, providing potential solutions to the localization of hand-held devices with cameras. In contrast to existing widely-applied indoor localization approaches, like vision-based and laser-based methods, our approach reveals its advantages as low-cost, globally consistent and it retains the potential applications using Visible Light Communication(VLC). We also study the characteristics of the proposed solutions under typical indoor conditions by experiments.

This paper presents the design and implementation of a VLC (visible light communication) transceiver complying with the Type-I physical layer (PHY-I) specified in IEEE 802.15.7 Standard. Both the system architectures and the building blocks are described in detail. The design is implemented by Verilog-HDL and verified on Xilinx Virtex-5 Field-Programmable Gate Arrays (FPGA). Layout implementation using ASIC development tools is also provided for the transmitter design. The system is targeted at information broadcasting with data rates from 11.67 kb/s to 266.6 kb/s. Measurement result proves that the system can achieve a bit error rate (BER) of 10-6 when the received illuminance is 18 lx. © 2014 IEEE.