Department Publications

Real-time image processing demands much more processing power than a conventional processor can deliver. As a result hardware acceleration became necessary to augments processors with application-specific coprocessors. Due to the limited resources on FPGA and nature of some sequential algorithms, it is difficult to depend entirely on slice resources. In this research, we implemented a multiprocessor architecture to support real-time image processing on FPGA. Furthermore, we benchmarked and compared our implemented architectures with their counterparts. The operational structure of multiprocessor architecture consists of on-chip processors implemented in a parallel manner with efficient memory and bus architectures. The performance properties such as accuracy, throughput and efficiency are measured and presented. Multiprocessor systems are effective in software level parallelism on FPGA. Our …

• Digital image processing helps us enhance images to make them visually pleasing, or accentuate regions or features of an image to better represent the content.

In object tracking identifying the best feature which discriminates object and background improves the performance. Most of the existing methods do not consider the suitability of such features for the tracker. Here we enhance the discriminative features which elevate the tracker performance. To accommodate object and background variations over time we dynamically update the best feature using a distance measure. We demonstrate the performance of the resulting systems on the UNIVERSITÄT KARLSRUHE Image Sequences.

Intelligent Assistance in Localiation for Mobile Robots - Shibaura Institute of Technology Skip to main navigation Skip to search Skip to main content Shibaura Institute of Technology Home Shibaura Institute of Technology Logo English 日本語 Search content at Shibaura Institute of Technology Home Profiles Research units Research output Activities Press/Media Prizes Intelligent Assistance in Localiation for Mobile Robots Peshala G. Jayasekara, Young Eun Song, Takeshi Sasaki, Hideki Hashimoto Functional Control Systems Research output: Contribution to journal › Article › peer-review Overview Original language English Pages (from-to) 317-322 Journal Default journal Publication status Published - 2010 Nov 23 Cite this APA Standard Harvard Vancouver Author BIBTEX RIS Powered by Pure Link opens in a new tab, Scopus Link opens in a new tab & Elsevier Fingerprint Engine™ Link opens in a new tab All …

Scintillation effect is a dominant atmospheric impairment among the various contributing factors for low fade margin communication systems operating on high frequency bands such as Ku. Empirical analysis of scintillations can be done using signal strength measurements which can be treated as a time series prediction problem in forecasting the short-term scintillation effect. This paper discusses the time series based statistical prediction analysis of tropospheric scintillation effect. The experiment was performed under clear sky conditions where the other attenuation contributions such as rain, dense clouds is minimum. The experiment was setup at the University of Moratuwa, Sri Lanka using a Ku band satellite downlink operating on a moderately high elevation angle of 45 degrees. The time series analysis was performed using linear, non-linear, fuzzy and neural prediction techniques. The results show that …

Beamforming, in brief, is a signal processing technique which has potential applications in the areas such as sonar, ultrasound, seismic, microwave imaging, radio astronomy and communications. In this report we are presenting a prototype that filters audio signals of interest, based on their direction of arrival (DOA). The prototype described in this report consists of both hardware and software. A microphone sensor array, low-noise-amplifiers, multiplexer, adjustable gain controller, FPGA development board and speakers constitute the hardware. FPGA processor is embedded with a 2D IIR beam filter. The hardware take the audio inputs, multiplex them, digitize them and finally fed them in to FPGA processor. The digital filter, filters the asynchronously sampled broadband spatio-temporal plane-wave signals based on DOA and yields a processed signal as the output. Further the report describes the synthesis of 2D IIR …

We saw that a given image may have a peaked histogram. Such a peaked or non-flat histogram shows that pixels do not equally occupy all the gray levels. This results in a low contrast image. We can remedy this by carrying out the operation called histogram equalization. Histogram equalization is a gray-level transformation that results in an image with a more or less flat histogram. Consider, for now, that continuous intensity values of an image are to be processed. We assume that r∈[0, L− 1]. Lets consider the intensity transformation s= T (r) 0≤ r≤ L− 1(3) that produces an output intensity level s for every pixel in the input image having intensity r. We assume that

Intelligent Localization Assistance for Mobile Robots Using Rao-Blackwellized Particle Filter Based Target Tracking - Shibaura Institute of Technology Skip to main navigation Skip to search Skip to main content Shibaura Institute of Technology Home Shibaura Institute of Technology Logo English 日本語 Home Profiles Research units Research output Activities Press/Media Prizes Search by expertise, name or affiliation Intelligent Localization Assistance for Mobile Robots Using Rao-Blackwellized Particle Filter Based Target Tracking Peshala G. Jayasekara, Takeshi Sasaki, Leon Palafox, Hideki Hashimoto Functional Control Systems Research output: Contribution to journal › Article › peer-review Overview Original language English Pages (from-to) 346-349 Journal Default journal Publication status Published - 2010 Nov 26 Cite this APA Standard Harvard Vancouver Author BIBTEX RIS Powered by Pure, Scopus & …

This paper proposes a new biologically inspired algorithm for optimization. The algorithm, called the Paddy Field Algorithm (PFA) operates by initially scattering seeds at random in the parameter space. The number of seeds of each plant depend on the function value such that a plant closer to the optimum solution produces the most seeds. Out of these, depending on the number of neighbors of the plant, only a percentage will become viable due to pollination. In order to prevent getting stuck in local minima, the seeds of each plant are dispersed. This algorithm is tested on four sample functions along side other conventional algorithms. The effect of various parameters on the performance of the algorithm is also investigated. Its performance is also tested with a hybrid algorithm. The results show that the algorithm performs well.

Robust feature tracking is a requirement for many computer vision tasks such as indoor robot navigation. However, indoor scenes are characterized by poorly localizable features. As a result, indoor feature tracking without artificial markers is challenging and remains an attractive problem. We propose to solve this problem by constraining the locations of a large number of nondistinctive features by several planar homographies which are strategically computed using distinctive features. We experimentally show the need for multiple homographies and propose an illumination-invariant local-optimization scheme for motion refinement. The use of a large number of nondistinctive features within the constraints imposed by planar homographies allows us to gain robustness. Also, the lesser computation cost in estimating these nondistinctive features helps to maintain the efficiency of the proposed method. Our local …

This paper proposes a novel method for a dynamic ridesharing mechanism using the combination of several modern information and communication technologies.

Quad Rotor unmanned aerial vehicle (UAV) is an aerial vehicle platform which has drawn much attention in the recent past due to its simple yet unique design. Despite the simplicity in the hardware, the vehicle is inherently unstable, and many control strategies have been proposed to achieve stability and control of the quad rotor platform. This paper presents a Fuzzy Logic based design to stabilize and control the quad rotor UAV. The fuzzy controller was designed and simulated along with a non-linear dynamic model of the quad rotor UAV. The fuzzy controller was then used to achieve stable hovering of the quad rotor UAV, amidst velocity disturbances. The simulation results show that stable hovering conditions can be achieved with the designed controller.

A single-chip FPGA implementation of a vision core is an efficient way to design fast and compact embedded vision systems from the PCB design level. The scope of the research is to design a novel FPGA-based parallel architecture for embedded vision entirely with on-chip FPGA resources. We designed it by utilizing block-RAMs and IO interfaces on the FPGA. As a result, the system is compact, fast and flexible. We evaluated this architecture for several mid-level neighborhood algorithms using Xilinx Virtex-2 Pro (XC2VP30) FPGA. Our algorithm uses a vision core with a 100 MHz system clock which supports image processing on a low-resolution image of 128×128 pixels up to 200 images per second. The results are accurate. We have compared our results with existing FPGA implementations. The performance of the algorithms could be substantially improved by applying sufficient parallelism.

Using a two-step, two-color laser spectroscopy technique, we have completed a measurement of the hyperfine structure within the excited state in . A frequency stabilized GaN diode laser at 410 nm is locked to the ground-state transition and a second 1291 nm diode laser is scanned over the transition to produce hyperfine spectra for the manifold. We find the hyperfine splittings of consecutive sublevels to be as follows: , , and . The magnetic dipole, electric quadrupole, and magnetic octupole hyperfine coupling constants derived from these three splittings are, respectively, , , and . The measured value of the dipole constant, , agrees to within 2% with a recent theoretical prediction.

This paper details the use of possibilistic decision trees for a lightweight Intrusion Detection System (IDS) to be used in Intelligent Electronic Devices (IEDs) of IEC61850 automated electric substations. Traffic data is captured by performing simulated attacks on IEDs. Data is obtained for two types of genuine user activity and two types of common malicious attacks on IEDs. The genuine user activity includes, casual browsing of IED data and downloading of IED data while a Ping flood Denial of Service (DoS) and password crack attack are performed for malicious attacks. Classification is done using possibilistic decision trees for the logarithmic histogram of the time difference between the arrival of two consecutive packets. The main contribution of this paper is the use of non-specificity for obtaining a continuous valued possibilistic decision tree and its cut points. It also includes the use of mean distance metrics to …

The study of empirical propagation models for mobile channels has been done extensively, but the applicability of those models to a Fixed Wireless Access (FWA) System is not appropriately tested. The candidate models include Hata - Okumura, COST 231 Hata, COST-Walfisch-Ikegami and Erceg. From those models Erceg model seems to be the most suitable. In this paper field measurements are taken for the 3.5GHz Fixed WiMAX network in Katubedda, Sri Lanka. Those are used to validate the applicability of the above mentioned propagation models in a sub urban environment in Sri Lanka.

The Axial Flux BLDC motors are relatively new, specially at higher power ratings over 10 kW. Therefore the designers face a lot of difficulties in designing and optimizing the motor for a given application. This paper presents a new method to optimize the performance in speed, torque, torque stability, power output, power density and motor dimensions in view of the cost and reliability for a given motor; specially to be used for traction purposes. By this method, the motor designers can easily choose the exact parameters of the motor to match the requirement and make sure of the optimization of the design. A software interface and simulation results are presented to check the level of optimization achievable with the system. This paper discusses a three phase axial flux outer rotor BLDC motor, but the core equations can be easily changed to simulate for any kind of motor with the same software and simulation interface.

Safety of critically ill patients in intensive care units is an important aspect of medical care. There are many factors contributing to shortcomings and errors in patient care in the intensive care setting, such as long working hours, high levels of stress, lack of enough people, may cause human errors and affecting the effectiveness of the decisions of the physician. Several attempts have been made to increase the effectiveness of such decisions by issuing early alerts on adverse patient conditions. However, such alerts are based on single parameter variations but not on the relationship between multiple parameter variations. Thus, inability to provide an effective communication model causes a considerable bottleneck in intensive care unit (ICU) operations. The proposed model is an integrated solution which identifies the adverse patient conditions on multiple parameter variations and then provides predictive treatment …

This paper presents a development of a holonomic mobile robot with remote operation capability. Most of the currently available holonomic mobile robots find problems in field applications because they has not been adopted to field environment.To address those problems we have develop a holonomic platform with a capability of carrying 30 kg payload. This platform use normal car type wheels and a complex multi-processor control system controls each wheels steering and driving to achieve the correct holonomic motion. We have tested it in indoor and out door environments and it's design , hardware and control is presented in this paper.

A web enabled visualization methodology is proposed in this work for viewing time varying spatial data. The technique is simple, and hence could be used by non experts of IT or GIS. The user can upload own datasets prepared in a given format with specific fields. The variation of time for data visualization can be adjusted. A web server and centralized GIS engine would process the data and the visualization would be sent to the web client as an animation. Spatial and temporal interpolation is used at the server side. In order to test the methodology, a GIS based Time-varying Spatial Information Visualizer is developed. The methodology is tested with local weather data. It can be used for visualization of demographic data as well. The methodology can be further developed to add forecasting facilities based on user provided data.

Let Z be a set of integers. The sampling process used to produce the digital image may be viewed as a partitioning in the xy-plane in to a grid, with coordinates of the center of each grid being a pair of elements from the Cartesian product Z2. In the terminology of set theory the function f (x, y) is said to be a digital image if (x, y) are integers from Z2 and f is a mapping that assigns an intensity value in the set of real numbers, R, to each distinct pair of coordinates (x, y). If the elements of R also are integers, a digital image then becomes a two-dimensional function, whose coordinates and the amplitude values are integers. Let A be a set in Z2, the elements of which are pixel coordinates (x, y). If w=(x, y) is an element of A, then we write w∈ A.

Bandwidth scarcity is a common problem faced in multimedia transmission over broadband wireless networks. From a consumer's perspective, the effectiveness of multimedia delivery suffers significantly in such networks. Further, in a mobile environment, when the number of users increases, they experience interruptions in the received multimedia streams. Adaptive streaming is one solution that can be adopted in any network environment regardless of the nature of the network. Adaptive streaming can be achieved using transcoding techniques. Transcoding is a mechanism that converts a video to a form that has less information so that the resulting data volume is appropriate for streaming over a low bandwidth network. However, the quality of the video stream drops due to transcoding. The advantage is that when there is a large number of users sharing the network, users could watch a video at a lower quality …

The determination of the motor and battery specification is one of the major challenges in the electric vehicle designs, specially considering the different kinds of requirements and specifications in different designs. This paper discusses about a method of simulating a vehicle in given terrains and driver models for extracting the torque, power and battery usage; and hence get the most optimized set of parameters for the given design requirement. The simulation takes the driver as a fuzzy model and the overall vehicle as a non-linear model for calculating the motor and battery requirements according to the terrain, driver commands and traffic condition.

This paper presents a real time non linear automatic UAV simulation test-bed and autonomous control implementation with way point navigation. This UAV simulator is an integrated product that combines a vehicle operator station with a synthetic environment to support UAV research, training and operations while providing the operators (Internal Pilot) with a consistent interface. the simulated air vehicle operates against simulated terrain, weather, and computer generated forces In the synthetic mission space. External pilot also interact into synthetic simulation test-bed. The autonomous control system is based on the Aerosonde UAV and major considerations of controller performance and minimum instability within manual and autonomous switching have been evaluated with full software simulation. Major requirements for the good control system are minimum overshoot, minimum setting time without undesirable …