Capsule endoscopy system with novel imaging algorithms

Wireless capsule endoscopy (WCE) is a state-of-the-art technology to receive images of human intestine for medical diagnostics. In WCE, the patient ingests a specially designed electronic capsule which has imaging and wireless transmission capabilities inside it. While the capsule travels through the gastrointestinal (GI) tract, it captures images and sends them wirelessly to an outside data logger unit. The data logger stores the image data and then they are transferred to a personal computer (PC) where the images are reconstructed and displayed for diagnosis. The key design challenge in WCE is to reduce the area and power consumption of the capsule while maintaining acceptable image reconstruction. In this research, the unique properties of WCE images are identified by analyzing hundreds of endoscopic images and video frames, and then these properties are used to develop novel and low complexity compression algorithms tailored for capsule endoscopy. The proposed image compressor consists of a new YEF color space converter, lossless prediction coder, customizable chrominance sub-sampler and an efficient Golomb-Rice encoder. The scheme has both lossy and lossless modes and is further customized to work with two lighting modes – conventional white light imaging (WLI) and emerging narrow band imaging (NBI). The average compression ratio achieved using the proposed lossy compression algorithm is 80.4% for WBI and 79.2% for NBI with high reconstruction quality index for both bands. Two surveys have been conducted which show that the reconstructed images have high acceptability among medical imaging doctors and gastroenterologists. The imaging algorithms have been realized in hardware description language (HDL) and their functionalities have been verified in field programmable gate array (FPGA) board. Later it was implemented in a 0.18 μm complementary metal oxide semiconductor (CMOS) technology and the chip was fabricated. Due to the low complexity of the core compressor, it consumes only 43 µW of power and 0.032 mm2 of area. The compressor is designed to work with commercial low-power image sensor that outputs image pixels in raster scan fashion, eliminating the need of significant input buffer memory. To demonstrate the advantage, a prototype of the complete WCE system including an FPGA based electronic capsule, a microcontroller based data logger unit and a Windows based image reconstruction software have been developed. The capsule contains the proposed low complexity image compressor and can generate both lossy and lossless compressed bit-stream. The capsule prototype also supports both white light imaging (WLI) and narrow band imaging (NBI) imaging modes and communicates with the data logger in full duplex fashion, which enables configuring the image size and imaging mode in real time during the examination. The developed data logger is portable and has a high data rate wireless connectivity including Bluetooth, graphical display for real time image viewing with state-of-the-art touch screen technology. The data are logged in micro SD cards and can be transferred to PC or Smartphone using card reader, USB interface, or Bluetooth wireless link. The workstation software can decompress and show the reconstructed images. The images can be navigated, marked, zoomed and can be played as video. Finally, ex-vivo testing of the WCE system has been done in pig's intestine to validate its performance

Bezprzewodowa Jednostka Audio

Mestrado em Engenharia ElectrónicaA presente tese pretende descrever o desenvolvimento de um sistema electrónico, cuja funcionalidade se baseia na transmissão de sinais áudio através da rede Wireless. Inicialmente foi estudada a família de microcontroladores PIC32, no qual se incluiu a sua forma de programação. Foi ainda realizada pesquisa acerca dos possíveis métodos de compressão de áudio, culminando com o desenvolvimento de algoritmos de compressão no software MATLAB. Seguidamente foi desenvolvida a PIC32 Module – daughterboard do projecto. Esta é uma componente universal que contém um microcontrolador PIC32, de fácil utilização em outros projectos. Posteriormente foi criado o dispositivo Wireless Audio Unit – o objectivo basilar desta tese. Este passo compreendeu a esquematização e PCB de ambas as partes: o transmissor e o receptor. Após a montagem, ambos os dispositivos forma colocados em caixas. O firmware dos dois microcontroladores PIC32 foi criado em linguagem de programação C. O ADC e o DAC são controlados pelo firmware do PIC32, estando a ser executadas correctamente as suas funções. No momento do desenvolvimento da componente escrita desta tese, ainda se mantêm alguns problemas associados à manipulação do transceptor. Por esta razão, o firmware WAU não foi terminado, e o dispositivo não cumpre, ainda, a sua funcionalidade.The thesis aims to report on the development of an electronic system, which task is to transmit wirelessly an audio signal. The work was started by studying the PIC32 family of microcontrollers including the way of programming. The research on audio compression methods that was made, finished with development of compression algorithms in MATLAB software. Following, the PIC32 Module – the daughterboard of project was designed. This part is universal unit containing PIC32 microcontroller, which could be easily used in many other projects. Afterwards, it was created the proper Wireless Audio Unit device – the main objective of this dissertation. This step included design of schematics and PCB for two its parts: transmitter and receiver. After assembling, both devices was put into enclosures. The firmware for two PIC32 microcontrollers was created in C programming language. The ADC and DAC are controlled by PIC32 firmware and are correctly realizing their functions. At the moment of writing this document, the problem with handling transceiver was not solved. For this reason the firmware WAU was not finished and the device does not have its functionality.Celem niniejszego dokumentu jest opis wykonanego systemu elektronicznego, którego zadaniem jest bezprzewodowa transmisja sygnału audio. Praca została rozpoczęta od zapoznania się z rodziną mikrokontrolerów PIC32, włączając w to poznanie metod ich programowania. Badania nad istniejącymi metodami kompresji audio, zostały uwieńczone opracowaniem algorytmów kompresji w oprogramowaniu MATLAB. Następnie został zaprojektowany moduł rozszerzenia - PIC32 Module. Jest to uniwersalna jednostka zawierająca mikrokontroler PIC32, która może być łatwo wykorzystana również w innych projektach. Kolejnym krokiem było stworzenie właściwego urządzenia – Wireless Audio Unit (Bezprzewodowa Jednostka Audio), będącego głównym celem tej pracy. Etap ten zawierał projekt schematu oraz płytki obwodu drukowanego dwóch części projektu: WAU Transmitter (Nadajnik) i WAU Receiver (odbiornik). Po montażu, oba urządzenia zostały umieszczone w obudowach. Oprogramowanie dla mikrokontrolerów PIC32 zostało stworzone w języku programowania C. Przetworniki a/c oraz c/a są kontrolowane przez mikrokontroler i poprawnie realizują swoje funkcje. W chwili powstawania tego raportu, problem z obsługą transceivera nie został rozwiązany. Z tego powodu, oprogramowanie dla mikrokontrolerów nie zostało ukończone i urządzenie nie posiada założonej funkcjonalności

Low complexity lossless compression of underwater sound recordings

Author Posting. © Acoustical Society of America, 2013. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 133 (2013): 1387-1398, doi:10.1121/1.4776206.Autonomous listening devices are increasingly used to study vocal aquatic animals, and there is a constant need to record longer or with greater bandwidth, requiring efficient use of memory and battery power. Real-time compression of sound has the potential to extend recording durations and bandwidths at the expense of increased processing operations and therefore power consumption. Whereas lossy methods such as MP3 introduce undesirable artifacts, lossless compression algorithms (e.g., flac) guarantee exact data recovery. But these algorithms are relatively complex due to the wide variety of signals they are designed to compress. A simpler lossless algorithm is shown here to provide compression factors of three or more for underwater sound recordings over a range of noise environments. The compressor was evaluated using samples from drifting and animal-borne sound recorders with sampling rates of 16–240 kHz. It achieves >87% of the compression of more-complex methods but requires about 1/10 of the processing operations resulting in less than 1 mW power consumption at a sampling rate of 192 kHz on a low-power microprocessor. The potential to triple recording duration with a minor increase in power consumption and no loss in sound quality may be especially valuable for battery-limited tags and robotic vehicles.Algorithm development was supported by SERDP, ONR, US Navy (N45) and NOPP. M.J. was supported by the Marine Alliance for Science and Technology Scotland (MASTS)

ECG compression for Holter monitoring

Cardiologists can gain useful insight into a patient's condition when they are able to correlate the patent's symptoms and activities. For this purpose, a Holter Monitor is often used - a portable electrocardiogram (ECG) recorder worn by the patient for a period of 24-72 hours. Preferably, the monitor is not cumbersome to the patient and thus it should be designed to be as small and light as possible; however, the storage requirements for such a long signal are very large and can significantly increase the recorder's size and cost, and so signal compression is often employed. At the same time, the decompressed signal must contain enough detail for the cardiologist to be able to identify irregularities. "Lossy" compressors may obscure such details, where a "lossless" compressor preserves the signal exactly as captured.The purpose of this thesis is to develop a platform upon which a Holter Monitor can be built, including a hardware-assisted lossless compression method in order to avoid the signal quality penalties of a lossy algorithm. The objective of this thesis is to develop and implement a low-complexity lossless ECG encoding algorithm capable of at least a 2:1 compression ratio in an embedded system for use in a Holter Monitor. Different lossless compression techniques were evaluated in terms of coding efficiency as well as suitability for ECG waveform application, random access within the signal and complexity of the decoding operation. For the reduction of the physical circuit size, a System On a Programmable Chip (SOPC) design was utilized. A coder based on a library of linear predictors and Rice coding was chosen and found to give a compression ratio of at least 2:1 and as high as 3:1 on real-world signals tested while having a low decoder complexity and fast random access to arbitrary parts of the signal. In the hardware-assisted implementation, the speed of encoding was a factor of between four and five faster than a software encoder running on the same CPU while allowing the CPU to perform other tasks during the encoding process

Técnicas de compresión de imágenes hiperespectrales sobre hardware reconfigurable

Tesis de la Universidad Complutense de Madrid, Facultad de Informática, leída el 18-12-2020Sensors are nowadays in all aspects of human life. When possible, sensors are used remotely. This is less intrusive, avoids interferces in the measuring process, and more convenient for the scientist. One of the most recurrent concerns in the last decades has been sustainability of the planet, and how the changes it is facing can be monitored. Remote sensing of the earth has seen an explosion in activity, with satellites now being launched on a weekly basis to perform remote analysis of the earth, and planes surveying vast areas for closer analysis...Los sensores aparecen hoy en día en todos los aspectos de nuestra vida. Cuando es posible, de manera remota. Esto es menos intrusivo, evita interferencias en el proceso de medida, y además facilita el trabajo científico. Una de las preocupaciones recurrentes en las últimas décadas ha sido la sotenibilidad del planeta, y cómo menitoirzar los cambios a los que se enfrenta. Los estudios remotos de la tierra han visto un gran crecimiento, con satélites lanzados semanalmente para analizar la superficie, y aviones sobrevolando grades áreas para análisis más precisos...Fac. de InformáticaTRUEunpu

High Performance Data Acquisition and Analysis Routines for the Nab Experiment

Probes of the Standard Model of particle physics are pushing further and further into the so-called “precision frontier”. In order to reach the precision goals of these experiments, a combination of elegant experimental design and robust data acquisition and analysis is required. Two experiments that embody this philosophy are the Nab and Calcium-45 experiments. These experiments are probing the understanding of the weak interaction by examining the beta decay of the free neutron and Calcium-45 respectively. They both aim to measure correlation parameters in the neutron beta decay alphabet, a and b. The parameter a, the electron-neutrino correlation coefficient, is sensitive to λ, the ratio of the axial-vector and vector coupling strengths in the decay of the free neutron. This parameter λ, in tandem with a precision measurement of the neutron lifetime τ , provides a measurement of the matrix element Vud from the CKM quark mixing matrix. The CKM matrix, as a rotation matrix, must be unitary. Probes of Vud and Vus in recent years have revealed tension in this unitarity at the 2.2σ level. The measurement of a via decay of free cold neutrons serves as an additional method of extraction for Vud that is sensitive to a different set of systematic effects and as such is an excellent probe into the source of the deviation from unitarity. The parameter b, the Fierz interference term, appears as a distortion in the mea- sured electron energy spectra from beta decay. This parameter, if non-zero, would indicate the existence of Scalar and/or Tensor couplings in the Weak interaction which according to the Standard Model is purely Vector minus Axial-Vector. This is therefore a search for physics beyond the standard model, BSM, physics search. The Nab and Calcium-45 experiments probe these parameters with a combination of elegant experimental design and brute force collection and analysis of large amounts of digitized detector data. These datasets, particularly in the case of the Nab experiment, are anticipated to span multiple petabytes of data and will require high performance online analysis and precision offline analysis routines in order to reach the experimental goals. Of particular note are the requirements for better than 3 keV energy resolution and an understanding of the uncertainty in the mean timing bias for the detected particles within 300 ps. Presented in this dissertation is an overview of the experiments and their design, a description of the data acquisition systems and analysis routines that have been developed to support the experiments, and a discussion of the data analysis performed for the Calcium-45 experiment

Parallel hardware architecture for JPEG-LS based on domain decomposition using context sets

This thesis investigates the scope of parallelism of the lossless JPEG-LS encoder. The input is not taken to be the entire image anymore; instead it is streams of pixels from an image sensor in every clock cycle. So the data dependencies that already exist due to the context modelling process and the effect of incomplete image data were analyzed thoroughly here. Other approaches of parallelism in JPEG-LS (e.g. pipelined hardware or software implementations that modify the context update procedures) deviate from the standard defined by ISO/ITU. On the other hand, the proposed technique here is fully compatible to the standard. In this work, a unique pixel loading mechanism (i.e. in the form that the encoder expects them to be) was developed from the streams of pixel. Later in order to store the pixels of the same context that are yet to be processed, another unique buffering mechanism was developed. However the context distribution of individual pixel determines the maximum achievable parallelism and thus a fixed value is not guaranteed in any case. The thesis also presents a vhdl implementation of the proposed parallel JPEG-LS encoder. The target hardware for this design was an FPGA board (Virtex 5). The design was also compared with the sequential hardware implementation and other parallel implementation in terms of speed up mainly. However there were some obstacles that restricted the actual synthesis. Possible reasons behind them are discussed with further suggestions for future work

Combined Industry, Space and Earth Science Data Compression Workshop

The sixth annual Space and Earth Science Data Compression Workshop and the third annual Data Compression Industry Workshop were held as a single combined workshop. The workshop was held April 4, 1996 in Snowbird, Utah in conjunction with the 1996 IEEE Data Compression Conference, which was held at the same location March 31 - April 3, 1996. The Space and Earth Science Data Compression sessions seek to explore opportunities for data compression to enhance the collection, analysis, and retrieval of space and earth science data. Of particular interest is data compression research that is integrated into, or has the potential to be integrated into, a particular space or earth science data information system. Preference is given to data compression research that takes into account the scien- tist's data requirements, and the constraints imposed by the data collection, transmission, distribution and archival systems

UWB communication systems acquisition at symbol rate sampling for IEEE standard channel models

For ultra-wideband (UWB) communications, acquisition is challenging. The reason is from the ultra short pulse shape and ultra dense multipath interference. Ultra short pulse indicates the acquisition region is very narrow. Sampling is another challenge for UWB design due to the need for ultra high speed analog-to digital converter.A sub-optimum and under-sampling scheme using pilot codes as transmitted reference is proposed here for acquisition. The sampling rate for the receiver is at the symbol rate. A new architecture, the reference aided matched filter is studied in this project. The reference aided matched filter method avoids using complex rake receiver to estimate channel parameters and high sampling rate for interpolation. A limited number of matched filters are used as a filter bank to search for the strongest path. Timing offset for acquisition is then estimated and passed to an advanced verification algorithm. For optimum performance of acquisition, the adaptive post detection integration is proposed to solve the problem from dense inter-symbol interference during the acquisition. A low-complex early-late gate tracking loop is one element of the adaptive post detection integration. This tracking scheme assists in improving acquisition accuracy. The proposed scheme is evaluated using Matlab Simulink simulations in term of mean acquisition time, system performance and false alarm. Simulation results show proposed algorithm is very effective in ultra dense multipath channels. This research proves reference aided acquisition with tracking loop is promising in UWB application