engleski

Quality of electrophoresis and isoelectric focusing images compressed using JPEG and JPEG2000

Aim: High quality of all image elements must be maintained for the purpose of telepathology. The aim of this study was to compress the images of electrophoresis and isoelectric focusing samples using JPEG (Joint Photographic Expert Group) and JPEG2000 algorithms, and to assess the quality of the compressed images before and after electronic transmission. Methods: Scanograms of serum protein electrophoresis samples of a patient with Zagreb albumin and albumin samples for isoelectric focusing of a patient with Krapina albumin were selected for the study together with a photographed scanogram of isoelectric focusing. Each image was compressed at eight compression rates (from 3.00 bpp (bit per pixel) to 0.1 bpp) using JPEG and JPEG2000 compression algorithms. All images (N = 51), both compressed and uncompressed, we retransmitted by email for assessment to eight medical biochemists: six from Croatia, one from Italy and one from Denmark. Image quality was also assessed by objective measures, i.e. compared to the quality of PSNR (Peak-Signal-to-Noise-Ratio), SNR (Signal-to-Noise-Ratio), OQF (Optimized Quality Factor) and MSE (Mean Squared Error) images. Results: All images compressed using the JPEG2000 algorithm were subjectively rated as excellent. Contrarily, images compressed using JPEG at 0.1 bpp were rated as completely useless, those at 0.2 bpp as moderately blurred, and those at 0.3-3.00 as excellent. At JPEG compression at 0.3 bpp, PSNR and SNR values corresponded to PSNR and SNR values obtained by JPEG2000 compression at 0.1 bpp.

JPEG; JPEG2000; image compression; image analysis; telemedicine; electrophoresis; isoelectric focusing

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