Temat: medical image compression

Skocz do pozycji: 1.

Tytuł:: Irreversible medical image compression: conditions of acceptability
Autorzy:: Przelaskowski, A.
Tematy:: irreversible compression
medical image compression
diagnostic accuracy
diagnostic image quality; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1965779.pdf Link otwiera się w nowym oknie
Opis:: Acceptance of irreversible image compression applicable to medical imagery is controversial in the medical community. The influence of this irreversible process on degradation of diagnostic image features is considered and how to preserve diagnostic accuracy. Fears, doubts, the disadvantages of the data distortion process and the advantages of safe and efficient irreversible compression for image information storage and interchange are discussed. The effects of compression on various image exams are analysed. The conclusion is that irreversible compression is not to be afraid of, but its characteristics should be well understood before implementing it in current practice.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Evaluation of mammogram compression efficiency
Ocena efektywności kompresji mammogramów
Autorzy:: Kukuła, Anna
Surowski, Paweł
Przelaskowski, Artur
Opis:: Background: Lossy image coding significantly improves performance over lossless methods, but a reliable control of diagnostic accuracy regarding compressed images is necessary. The acceptable range of compression ratios must be safe with respect to as many objective criteria as possible. This study evaluates the compression efficiency of digital mammograms in both numerically lossless (reversible) and lossy (irreversible) manner. Effective compression methods and concepts were examined to increase archiving and telediagnosis performance. Materials/Methods Lossless compression as a primary applicable tool for medical applications was verified on a set 131 mammograms. Moreover, nine radiologists participated in the evaluation of lossy compression of mammograms. Subjective rating of diagnostically important features brought a set of mean rates given for each test image. The lesion detection test resulted in binary decision data analyzed statistically. The radiologists rated and interpreted malignant and benign lesions, representative pathology symptoms, and other structures susceptible to compression distortions contained in 22 original and 62 reconstructed mammograms. Test mammograms were collected in two radiology centers for three years and then selected according to diagnostic content suitable for an evaluation of compression effects. Results: Lossless compression efficiency of the tested coders varied, but CALIC, JPEG-LS, and SPIHT performed the best. The evaluation of lossy compression effects affecting detection ability was based on ROC-like analysis. Assuming a two-sided significance level of p=0.05, the null hypothesis that lower bit rate reconstructions are as useful for diagnosis as the originals was false in sensitivity tests with 0.04 bpp mammograms. However, verification of the same hypothesis with 0.1 bpp reconstructions suggested their acceptance. Moreover, the 1 bpp reconstructions were rated very similarly to the original mammograms in the diagnostic quality evaluation test, but the quality of 0.6 bpp and 0.1 bpp reconstructions was decreased. Conclusions: The compression performance of the most effective reversible coders is rather unsatisfactory. The subjective rating with the diagnostic criteria of image quality was more sensitive to distortions caused by lossy compression compared with the pathology detection test. The observers constituted 14:1 as the accepted ratio of lossy wavelet compression for test mammograms. This is significantly higher than the mean ratio of 2:1 achieved with lossless methods.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: Compression of image sequences in interactive medical teleconsultations
Autorzy:: Malawski, F.
Czekierda, Ł.
Tematy:: image compression
medical teleconsultations
telemedicine; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/305585.pdf Link otwiera się w nowym oknie
Opis:: Interactive medical teleconsultations are an important tool in modern medical practice. Their applications include remote diagnostics, conferences, work- shops, and classes for students. In many cases, standard medium or low-end machines are employed, and the teleconsultation systems must be able to provide a high quality of user experience with very limited resources. Particularly problematic are large datasets consisting of image sequences that need to be accessed fluently. The main issue is insufficient internal memory; therefore, proper compression methods are crucial. However, a scenario where image sequences are kept in a compressed format in the internal memory and decompressed on- the-fly when displayed is difficult to implement due to performance issues. In this paper, we present methods for both lossy and lossless compression of medical image sequences that only require compatibility with the Pixel Shader 2.0 standard, which is present even on relatively old, low-end devices. Based on the evaluation of quality, size reduction, and performance, these methods have been proven to be suitable and beneficial for medical teleconsultation applications
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The JPEG2000 standard for medical image applications
Autorzy:: Przelaskowski, A.
Tematy:: image compression
JPEG 2000
medical images
wavelet coding
medical information systems; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1965817.pdf Link otwiera się w nowym oknie
Opis:: A new standard of still image compression is characterised in the context of medical applications. Wide spectrum of JPEG2000 features is analysed with respect to its application potential to improve the performance of modern medical services (i.e. telemedicine, PACS, radiology information systems, wireless personal/home health care systems). Image data security techniques, error resilience technologies, client-side interactive Region of Interest (ROI) transmission and decoding (e.g. for teleconsultation with very large radiography exams), and storage of multiple image data sets are considered in detail. Selected tests of coders realized according to parts I and II of JPEG2000 for different modality test images are presented to evaluate the compression efficacy of this standard. Exemplary results of encoding process optimisation by wavelet transform and subband decomposition selection and screen-shots of software interfaces designed for these tests are also presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The half-byte descriptor for image data units
Autorzy:: Czapla, Z.
Tematy:: półbajtowy format obrazu
obraz medyczny
kompresja obrazu
half-byte image format
medical images
image compression; Pokaż więcej
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Powiązania:: https://bibliotekanauki.pl/articles/333850.pdf Link otwiera się w nowym oknie
Opis:: The paper presents proposal for image data unit description using a half-byte format. It was implemented for medical images description. The introduced definitions express pixel values using differences between pixels and the introduced base value. This way the image recorded at half-byte format can be simply compressed by an appropriate compression, methods more effectively. The half-byte format is suitable for so called "natural" images with textures that are usually compressed with not satisfying results. For the given method illustration some example results were introduced.
Dostawca treści:: Biblioteka Nauki

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