1,538 research outputs found

    Memristor-Based Digital Systems Design and Architectures

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    Memristor is considered as a suitable alternative solution to resolve the scaling limitation of CMOS technology. In recent years, the use of memristors in circuits design has rapidly increased and attracted researcher’s interest. Advances have been made to both size and complexity of memristor designs. The development of CMOS transistors shows major concerns, such as, increased leakage power, reduced reliability, and high fabrication cost. These factors have affected chip manufacturing process and functionality severely. Therefore, the demand for new devices is increasing. Memristor, is considered as one of the key element in memory and information processing design due to its small size, long-term data storage, low power, and CMOS compatibility. The main objective in this research is to design memristor-based arithmetic circuits and to overcome some of the Memristor based logic design issues. In this thesis, a fast, low area and low power hybrid CMOS memristor based digital circuit design were implemented. Small and large-scale memristor based digital circuits are implemented and provided a solutions for overcoming the memristor degradation and fan-out challenges. As an example, a 4- bit LFSR has been implemented by using MRL scheme with 64 CMOS devices and 64 memristors. The proposed design is more efficient in terms of the area when compared with CMOS- based LFSR circuits. The simulation results proves the functionality of the design. This approach presents acceptable speed in comparison with CMOS-based design and it is faster than IMPLY-based memrisitive LFSR. The propped LFSR has 841 ps de-lay. Furthermore, the proposed design has a significant power reduction of over 66% less than CMOS-based approach. This thesis proposes implementation of memristive 2-D median filter and extends previously published works on memristive Filter design to include this emerging technology characteristics in image processing. The proposed circuit was designed based on Pt/TaOx/Ta redox-based device and Memristor Ratioed Logic (MRL). The proposed filter is designed in Cadence and the memristive median approved tested circuit is translated to Verilog-XL as a behavioral model. Different 512 _ 512 pixels input images contain salt and pepper noise with various noise density ratios are applied to the proposed median filter and the design successfully has substantially removed the noise. The implementation results in comparison with the conventional filters, it gives better Peak Signal to Noise Ratio (PSNR) and Mean Absolute Error (MAE) for different images with different noise density ratios while it saves more area as compared to CMOS-based design. This dissertation proposes a comprehensive framework for design, mapping and synthesis of large-scale memristor-CMOS circuits. This framework provides a synthesis approach that can be applied to all memristor-based digital logic designs. In particular, it is a proposal for a characterization methodology of memristor-based logic cells to generate a standard cell library for large scale simulation. The proposed framework is implemented in the Cadence Virtuoso schematic-level environment and was veri_ed with Verilog-XL, MATLAB, and the Electronic Design Automation (EDA) Synopses compiler after being translated to the behavioral level. The proposed method can be applied to implement any digital logic design. The frame work is deployed for design of the memristor-based parallel 8-bit adder/subtractor and a 2-D memristive-based median filter

    Adaptive polyphase subband decomposition structures for image compression

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    Cataloged from PDF version of article.Subband decomposition techniques have been extensively used for data coding and analysis. In most filter banks, the goal is to obtain subsampled signals corresponding to different spectral regions of the original data. However, this approach leads to various artifacts in images having spatially varying characteristics, such as images containing text, subtitles, or sharp edges. In this paper, adaptive filter banks with perfect reconstruction property are presented for such images. The filters of the decomposition structure which can be either linear or nonlinear vary according to the nature of the signal. This leads to improved image compression ratios. Simulation examples are presented

    Characteristics of a detail preserving nonlinear filter.

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    by Lai Wai Kuen.Thesis (M.Phil.)--Chinese University of Hong Kong, 1993.Includes bibliographical references (leaves [119-125]).Abstract --- p.iAcknowledgement --- p.iiTable of Contents --- p.iiiChapter Chapter 1 --- IntroductionChapter 1.1 --- Background - The Need for Nonlinear Filtering --- p.1.1Chapter 1.2 --- Nonlinear Filtering --- p.1.2Chapter 1.3 --- Goal of the Work --- p.1.4Chapter 1.4 --- Organization of the Thesis --- p.1.5Chapter Chapter 2 --- An Overview of Robust Estimator Based Filters Morphological FiltersChapter 2.1 --- Introduction --- p.2.1Chapter 2.2 --- Signal Representation by Sets --- p.2.2Chapter 2.3 --- Robust Estimator Based Filters --- p.2.4Chapter 2.3.1 --- Filters based on the L-estimators --- p.2.4Chapter 2.3.1.1 --- The Median Filter and its Derivations --- p.2.5Chapter 2.3.1.2 --- Rank Order Filters and Derivations --- p.2.9Chapter 2.3.2 --- Filters based on the M-estimators (M-Filters) --- p.2.11Chapter 2.3.3 --- Filter based on the R-estimators --- p.2.13Chapter 2.4 --- Filters based on Mathematical Morphology --- p.2.14Chapter 2.4.1 --- Basic Morphological Operators --- p.2.14Chapter 2.4.2 --- Morphological Filters --- p.2.18Chapter 2.5 --- Chapter Summary --- p.2.20Chapter Chapter 3 --- Multi-Structuring Element Erosion FilterChapter 3.1 --- Introduction --- p.3.1Chapter 3.2 --- Problem Formulation --- p.3.1Chapter 3.3 --- Description of Multi-Structuring Element Erosion Filter --- p.3.3Chapter 3.3.1 --- Definition of Structuring Element for Multi-Structuring Element Erosion Filter --- p.3.4Chapter 3.3.2 --- Binary multi-Structuring Element Erosion Filter --- p.3.9Chapter 3.3.3 --- Selective Threshold Decomposition --- p.3.10Chapter 3.3.4 --- Multilevel Multi-Structuring Element Erosion Filter --- p.3.15Chapter 3.3.5 --- A Combination of Multilevel Multi-Structuring Element Erosion Filter and its Dual --- p.3.21Chapter 3.4 --- Chapter Summary --- p.3.21Chapter Chapter 4 --- Properties of Multi-Structuring Element Erosion FilterChapter 4.1 --- Introduction --- p.4.1Chapter 4.2 --- Deterministic Properties --- p.4.2Chapter 4.2.1 --- Shape of Invariant Signal --- p.4.3Chapter 4.2.1.1 --- Binary Multi-Structuring Element Erosion Filter --- p.4.5Chapter 4.2.1.2 --- Multilevel Multi-Structuring Element Erosion Filter --- p.4.16Chapter 4.2.2 --- Rate of Convergence of Multi-Structuring Element Erosion Filter --- p.4.25Chapter 4.2.2.1 --- Convergent Rate of Binary Multi-Structuring Element Erosion Filter --- p.4.25Chapter 4.2.2.2 --- Convergent Rate of Multilevel Multi-Structuring Element Erosion Filter --- p.4.28Chapter 4.3 --- Statistical Properties --- p.4.30Chapter 4.3.1 --- Output Distribution of Multi-Structuring Element Erosion Filter --- p.4.30Chapter 4.3.1.1 --- One-Dimensional Statistical Analysis of Multilevel Multi-Structuring Element Erosion Filter --- p.4.31Chapter 4.3.1.2 --- Two-Dimensional Statistical Analysis of Multilevel Multi-Structuring Element Erosion Filter --- p.4.32Chapter 4.3.2 --- Discussions on Statistical Properties --- p.4.36Chapter 4.4 --- Chapter Summary --- p.4.40Chapter Chapter 5 --- Performance EvaluationChapter 5.1 --- Introduction --- p.5.1Chapter 5.2 --- Performance Criteria --- p.5.2Chapter 5.2.1 --- Noise Suppression --- p.5.5Chapter 5.2.2 --- Subjective Criterion --- p.5.16Chapter 5.2.3 --- Computational Requirement --- p.5.20Chapter 5.3 --- Chapter Summary --- p.5.23Chapter Chapter 6 --- Recapitulation and Suggestions for Further WorkChapter 6.1 --- Recapitulation --- p.6.1Chapter 6.2 --- Suggestions for Further Work --- p.6.4Chapter 6.2.1 --- Probability Measure Function for the Two-Dimensional Filter --- p.6.4Chapter 6.2.2 --- Hardware Implementation --- p.6.5ReferencesAppendice

    Convolutional Deblurring for Natural Imaging

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    In this paper, we propose a novel design of image deblurring in the form of one-shot convolution filtering that can directly convolve with naturally blurred images for restoration. The problem of optical blurring is a common disadvantage to many imaging applications that suffer from optical imperfections. Despite numerous deconvolution methods that blindly estimate blurring in either inclusive or exclusive forms, they are practically challenging due to high computational cost and low image reconstruction quality. Both conditions of high accuracy and high speed are prerequisites for high-throughput imaging platforms in digital archiving. In such platforms, deblurring is required after image acquisition before being stored, previewed, or processed for high-level interpretation. Therefore, on-the-fly correction of such images is important to avoid possible time delays, mitigate computational expenses, and increase image perception quality. We bridge this gap by synthesizing a deconvolution kernel as a linear combination of Finite Impulse Response (FIR) even-derivative filters that can be directly convolved with blurry input images to boost the frequency fall-off of the Point Spread Function (PSF) associated with the optical blur. We employ a Gaussian low-pass filter to decouple the image denoising problem for image edge deblurring. Furthermore, we propose a blind approach to estimate the PSF statistics for two Gaussian and Laplacian models that are common in many imaging pipelines. Thorough experiments are designed to test and validate the efficiency of the proposed method using 2054 naturally blurred images across six imaging applications and seven state-of-the-art deconvolution methods.Comment: 15 pages, for publication in IEEE Transaction Image Processin

    3-dimensional median-based algorithms in image sequence processing

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    Ankara : Department of Electrical and Electronics Engineering and the Institute of Engineering and Sciences of Bilkent University, 1990.Thesis (Master's) -- Bilkent University, 1990.Includes bibliographical references leaves 75-78.This thesis introduces new 3-dimensional median-based algorithms to be used in two of the main research areas in image sequence proc(',ssi,ng; image sequence enhancement and image sequence coding. Two new nonlinear filters are developed in the field of image sequence enhancement. The motion performances and the output statistics of these filters are evaluated. The simulations show that the filters improve the image quality to a large extent compared to other examples from the literature. The second field addressed is image sequence coding. A new 3-dimensional median-based coding and decoding method is developed for stationary images with the aim of good slow motion performance. All the algorithms developed are simulated on real image sequences using a video sequencer.Alp, MĂĽnire BilgeM.S

    Study and development of a reliable fiducials-based localization system for multicopter UAVs flying indoor

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    openThe recent evolution of technology in automation, agriculture, IoT, and aerospace fields has created a growing demand for mobile robots capable of autonomous operation and movement to accomplish various tasks. Aerial platforms are expected to play a central role in the future due to their versatility and swift intervention capabilities. However, the effective utilization of these platforms faces a significant challenge due to localization, which is a vital aspect for their interaction with the surrounding environment. While GNSS localization systems have established themselves as reliable solutions for open-space scenarios, the same approach is not viable for indoor settings, where localization remains an open problem as it is witnessed by the lack of extensive literature on the topic. In this thesis, we address this challenge by proposing a dependable solution for small multi-rotor UAVs using a Visual Inertial Odometry localization system. Our KF-based localization system reconstructs the pose by fusing data from onboard sensors. The primary source of information stems from the recognition of AprilTags fiducial markers, strategically placed in known positions to form a “map”. Building upon prior research and thesis work conducted at our university, we extend and enhance this system. We begin with a concise introduction, followed by a justification of our chosen strategies based on the current state of the art. We provide an overview of the key theoretical, mathematical, and technical aspects that support our work. These concepts are fundamental to the design of innovative strategies that address challenges such as data fusion from different AprilTag recognition and the elimination of misleading measurements. To validate our algorithms and their implementation, we conduct experimental tests using two distinct platforms by using localization accuracy and computational complexity as performance indices to demonstrate the practical viability of our proposed system. By tackling the critical issue of indoor localization for aerial platforms, this thesis tries to give some contribution to the advancement of robotics technology, opening avenues for enhanced autonomy and efficiency across various domains.The recent evolution of technology in automation, agriculture, IoT, and aerospace fields has created a growing demand for mobile robots capable of autonomous operation and movement to accomplish various tasks. Aerial platforms are expected to play a central role in the future due to their versatility and swift intervention capabilities. However, the effective utilization of these platforms faces a significant challenge due to localization, which is a vital aspect for their interaction with the surrounding environment. While GNSS localization systems have established themselves as reliable solutions for open-space scenarios, the same approach is not viable for indoor settings, where localization remains an open problem as it is witnessed by the lack of extensive literature on the topic. In this thesis, we address this challenge by proposing a dependable solution for small multi-rotor UAVs using a Visual Inertial Odometry localization system. Our KF-based localization system reconstructs the pose by fusing data from onboard sensors. The primary source of information stems from the recognition of AprilTags fiducial markers, strategically placed in known positions to form a “map”. Building upon prior research and thesis work conducted at our university, we extend and enhance this system. We begin with a concise introduction, followed by a justification of our chosen strategies based on the current state of the art. We provide an overview of the key theoretical, mathematical, and technical aspects that support our work. These concepts are fundamental to the design of innovative strategies that address challenges such as data fusion from different AprilTag recognition and the elimination of misleading measurements. To validate our algorithms and their implementation, we conduct experimental tests using two distinct platforms by using localization accuracy and computational complexity as performance indices to demonstrate the practical viability of our proposed system. By tackling the critical issue of indoor localization for aerial platforms, this thesis tries to give some contribution to the advancement of robotics technology, opening avenues for enhanced autonomy and efficiency across various domains

    Video Deinterlacing using Control Grid Interpolation Frameworks

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    abstract: Video deinterlacing is a key technique in digital video processing, particularly with the widespread usage of LCD and plasma TVs. This thesis proposes a novel spatio-temporal, non-linear video deinterlacing technique that adaptively chooses between the results from one dimensional control grid interpolation (1DCGI), vertical temporal filter (VTF) and temporal line averaging (LA). The proposed method performs better than several popular benchmarking methods in terms of both visual quality and peak signal to noise ratio (PSNR). The algorithm performs better than existing approaches like edge-based line averaging (ELA) and spatio-temporal edge-based median filtering (STELA) on fine moving edges and semi-static regions of videos, which are recognized as particularly challenging deinterlacing cases. The proposed approach also performs better than the state-of-the-art content adaptive vertical temporal filtering (CAVTF) approach. Along with the main approach several spin-off approaches are also proposed each with its own characteristics.Dissertation/ThesisM.S. Electrical Engineering 201

    Multi-modal video analysis for early fire detection

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    In dit proefschrift worden verschillende aspecten van een intelligent videogebaseerd branddetectiesysteem onderzocht. In een eerste luik ligt de nadruk op de multimodale verwerking van visuele, infrarood en time-of-flight videobeelden, die de louter visuele detectie verbetert. Om de verwerkingskost zo minimaal mogelijk te houden, met het oog op real-time detectie, is er voor elk van het type sensoren een set ’low-cost’ brandkarakteristieken geselecteerd die vuur en vlammen uniek beschrijven. Door het samenvoegen van de verschillende typen informatie kunnen het aantal gemiste detecties en valse alarmen worden gereduceerd, wat resulteert in een significante verbetering van videogebaseerde branddetectie. Om de multimodale detectieresultaten te kunnen combineren, dienen de multimodale beelden wel geregistreerd (~gealigneerd) te zijn. Het tweede luik van dit proefschrift focust zich hoofdzakelijk op dit samenvoegen van multimodale data en behandelt een nieuwe silhouet gebaseerde registratiemethode. In het derde en tevens laatste luik van dit proefschrift worden methodes voorgesteld om videogebaseerde brandanalyse, en in een latere fase ook brandmodellering, uit te voeren. Elk van de voorgestelde technieken voor multimodale detectie en multi-view lokalisatie zijn uitvoerig getest in de praktijk. Zo werden onder andere succesvolle testen uitgevoerd voor de vroegtijdige detectie van wagenbranden in ondergrondse parkeergarages
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