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A.A. Kamdeu Fansi, P. Harasymowycz, D. Descovich, M.L. Belair; Using HRT for Telemedicine in Glaucoma Screening: The Effect of Different Image File Format on Diagnosis of Glaucoma . Invest. Ophthalmol. Vis. Sci. 2003;44(13):3379.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To investigate which compression format is acceptable for teleopthalmology transmission using Heidelberg Retina tomographic (HRT) images in glaucoma. Methods: Thirty-three eyes of 33 patients were scanned with HRT (11 normals, 11glaucoma suspects and 11 glaucoma patients). Digital images were transformed using Photoshop 7.0 and Lurawave Photoshop Plug-in into different file formats : Tagged Image File Format (TIFF), Graphic Interchange Format (GIF), Portable Network Graphics (PNG), Joint Photographic Experts Group JPEG (ratio 20:1, 40:1, 80:1) and JPEG 2000 (ratio 20:1, 40:1, 80:1) formats. 297 images were analyzed by three ophthalmologists with differing levels of glaucoma experience, without knowing the name of patients, their initial diagnosis, nor the file format. Diagnosis based on different HRT images was compared between observers. Results: The diagnostic agreement differed between different format files. The Kappa of the TIFF format was 0.804; 0.801 and 0.790 respectively for the three ophthalmologists. For the JPEG2000 format (ratio 20:1, 40:1), it was 0.780, 0.777 and 0.760, for JPEG format (ratio 20:1, 40:1, 80:1) it was 0.750, 0.745, 0.730. With PNG and GIF format, Kappa was not significant. The JPEG2000 format was highly interesting because of its small disk space capacity Conclusions: The JPEG 2000 wavelet compression in a ratio not greater than 40:1 has acceptable interobserver agreement and can be useful for image transmission and storage in telemedicine. The traditional JPEG and TIFF formats can also be useful alternatives but they occupy more disk space than JPEG 2000 View OriginalDownload SlideView OriginalDownload Slide
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