<p>The use of computers for handling image data in the healthcare is growing. The amount of data produced by modern image generating techniques, such as CT and MR, is vast. The amount of data might be a problem from a storage point of view or when the data is sent over a network. To overcome these problems data compression techniques adapted to these applications are needed. There are an abundant number of compression schemes for the compression of images, but few that are geared towards compression of image stacks. Though these 2D techniques can be applied to the image stacks they do not fully exploit the three-dimensional nature of the stacks. In this thesis ideas from the image compression area are extended to exploit the 3D nature of image stacks. Attention is directed to MR and CT stacks. The compression schemes in this thesis are based on the relatively new notion of wavelets, used in the JPEG2000 standard. The schemes also providea quality progressive transmission, which allows intermediate low-quality results to be constructed. Two different coders are presented in this thesis both developed for the compression of image stacks containing medical data. They are evaluated and compared and a top performer is chosen. Advantages and drawbacks of the schemes and future enhancements are also discussed.</p>

In this thesis, a low bit rate video coding system based on three-dimensional (3-D) wavelet coding is studied. In addition to the initial motivation to make use of the motion compensated wavelet based coding schemes, the other techniques that do not utilize the motion compensation in their coding procedures have also been considered on equal footing. The 3-D wavelet transform (WT) algorithm is based on the &ldquo / group of frames&rdquo / (GOF) concept. The group of eight frames are decomposed both temporally and spatially to their coarse and detail parts. The decomposition process utilizes both orthogonal and bi-orthogonal wavelet analysis filters. The transform coefficients are coded using an embedded image coding algorithm, called the &ldquo / Two-Dimensional Set Partitioning in Hierarchical Trees&rdquo / (2-D SPIHT). Due to its nature, the 2-D SPIHT is applied to the individual subband frames. In the reconstruction phase, the 2-D SPIHT decoding algorithm and the wavelet synthesis filters are employed, respectively. The Peak Signal to Noise Ratios (PSNRs) are used as a quality measure of the reconstructed frames. The investigations reveal that among several factors, the multi-level (de)composition is the dominant one effective both on the signal compression and the PSNR level. The encoded videos compressed to the ratio of 1:9 are reconstructed with the PSNR of about 30 dB in the best cases.

Generally, image viewers do not include the scalability for the image compressionand ecient encoding and decoding for easy transmission. They alsonever consider the specic requirements of the heterogeneous networks constitutedby the Global Packet Radio Service(GPRS), Universal Mobile TelecommunicationSystem(UMTS), Wireless Local Area Network(WLAN) and DigitalVideo Broadcasting(DVB-H). This work contains the medical application withviewer for the Digital Imaging and Communications in Medicine(DICOM) imagesas its core content. This application discusses the scalable wavelet-basedcompression, retrival and the decompression of the DICOM images. This proposedapplication is compatible with the mobile phones activated in the heterogeneousnetwoks. This paper also explains about the performance issues whenthis application is used in prototype heterogenous networks.

<p>At Saab Aerosystems, situated in Linköping Sweden, there is a presentation and manoeuvre simulator simulating the fighter jet JAS-39 Gripen. This flight simulator is called PMSIM. In this thesis we study how to transfer sensor images generated by PMSIM to other simulators or desktop computers. The transmission is band-limited so some kind of image coding must be used. Because of this the greater part of this thesis is concerned with image coding. </p><p>To fulfill the real time requirement the image coding has to be quite simple and the transmission has to be fast. To achieve fast transmission the network protocol has to use as little overhead information as possible. Such a protocol has therefore been designed and implemented. </p><p>This report also includes a survey about real radio links. This survey investigates how the quality of the video stream can be affected by noise and other disturbing elements. </p><p>The work in this report revolves around the implementation of a video link. The purpose of this link is to transmit and display sensor images. The link consists mainly of the three following parts: image coder, network link and image player. The image coding has been focused on MPEG and wavelets. </p><p>The wavelet technique is not a well known coding principle for video applications. Although as a coding technique for still images the technique is well known. For instance it is used in the JPEG2000-standard. Experiments conducted and published in this report suggest that for some applications the wavelet technique can be a viable candidate, with respect to the MPEG technique, for a video coder.</p>

At Saab Aerosystems, situated in Linköping Sweden, there is a presentation and manoeuvre simulator simulating the fighter jet JAS-39 Gripen. This flight simulator is called PMSIM. In this thesis we study how to transfer sensor images generated by PMSIM to other simulators or desktop computers. The transmission is band-limited so some kind of image coding must be used. Because of this the greater part of this thesis is concerned with image coding. To fulfill the real time requirement the image coding has to be quite simple and the transmission has to be fast. To achieve fast transmission the network protocol has to use as little overhead information as possible. Such a protocol has therefore been designed and implemented. This report also includes a survey about real radio links. This survey investigates how the quality of the video stream can be affected by noise and other disturbing elements. The work in this report revolves around the implementation of a video link. The purpose of this link is to transmit and display sensor images. The link consists mainly of the three following parts: image coder, network link and image player. The image coding has been focused on MPEG and wavelets. The wavelet technique is not a well known coding principle for video applications. Although as a coding technique for still images the technique is well known. For instance it is used in the JPEG2000-standard. Experiments conducted and published in this report suggest that for some applications the wavelet technique can be a viable candidate, with respect to the MPEG technique, for a video coder.

This diploma thesis deals with the problem of using an objective quality assessment methods in image data compression. Lossy compression always introduces some kind of distortion into the processed data causing degradation in the quality of the image. The intensity of this distortion can be measured using subjective or objective methods. To be able to optimize compression algorithms the objective criteria are used. In this work the SSIM index as a useful tool for describing the quality of compressed images has been presented. Lossy compression scheme is realized using the wavelet transform and SPIHT algorithm. The modification of this algorithm using partitioning of the wavelet coefficients into the separate tree-preserving blocks followed by independent coding, which is especially suitable for parallel processing, was implemented. For the given compression ratio the traditional problem is being solved – how to allocate available bits among the spatial blocks to achieve the highest possible image quality. The possible approaches to achieve this solution were discussed. As a result, some methods for bit allocation based on MSSIM index were proposed. To test the effectivity of these methods the MATLAB environment was used.

This work deals with image compression using wavelet transformation. At the beginning , you can find theoretical information about the best known techniques used for image compression , a thorough description of wavelet transormation and the EBCOT algorithm. A significant part of the work is devoted to the library's own implementation . Another chapter of the diploma thesis deals with the comparison and evaluation of the achieved results of the processed library with the JPEG2000 format

Ztrátová komprese signálů EKG je užitečná a v současnosti stále se rozvíjející oblast. Stále se vyvíjí nové a nové kompresní algoritmy. V této oblasti ale chybí standardy pro hodnocení kvality signálu po kompresi. Existuje tedy sice mnoho různých kompresních algoritmů, které ale buď nelze objektivně porovnat vůbec, nebo jen zhruba. V oblasti komprese navíc nikde není popsáno, zda mají na výkon kompresních algoritmů vliv patologie, popřípadě jaký. Tato dizertační práce poskytuje přehled všech nalezených metod pro hodnocení kvality signálů EKG po kompresi. Navíc bylo vytvořeno 10 nových metod. V rámci práce byla provedena analýza všech těchto metod a na základě jejích výsledků bylo doporučeno 12 metod vhodných pro hodnocení kvality signálu EKG po kompresi. Také je zde představen nový kompresní algoritmus „Single-Cycle Fractal-Based (SCyF)“. Algoritmus SCyF je inspirován metodou založenou na fraktálech a využívá jednoho cyklu signálu EKG jako domény. Algoritmus SCyF byl testován na čtyřech různých databázích, přičemž kvalita signálů po kompresi byla vyhodnocena 12 doporučenými metodami. Výsledky byly porovnány s velmi populárním kompresním algoritmem založeným na vlnkové transformaci, který využívá metodu „Set Partitioning in Hierarchical Trees (SPIHT)“. Postup testování zároveň slouží jako příklad, jak by měl vypadat standard hodnocení výkonu kompresních algoritmů. Dále bylo statisticky prokázáno, že existuje rozdíl mezi kompresí fyziologických a patologických signálů. Patologické signály byly komprimovány s nižší efektivitou a kvalitou než signály fyziologické.

This thesis deals with image compression using wavelet, contourlet and shearlet transformation. It starts with quick look at image compression problem a quality measurement. Next are presented basic concepts of wavelets, multiresolution analysis and scaling function and detailed look at each transform. Representatives of algorithms for coeficients coding are EZW, SPIHT and marginally EBCOT. In second part is described design and implementation of constructed library. Last part compare result of transforms with format JPEG 2000. Comparison resulted in determining type of image in which implemented contourlet and shearlet transform were more effective than wavelet. Format JPEG 2000 was not exceeded.

This paper represents the most well-known compression methods, which have been published. A Compression of ECG signal is important primarily for space saving in memory cards or efficiency improvement of data transfer. An application of wavelet transform for compression is a worldwide discussed topic and this is the reason why the paper focuses in this direction. Gained wavelet coefficients might be firstly quantized and then compressed using suitable method. There are many options for a selection of wavelet and a degree of decomposition, which will be tested from the point of view of the most efficient compression of ECG signal.