3가지 종류 CR 영상의 DICOM JPEG 압축률 비교와 시각적으로 손상이 되지 않는 비가역 영상 압축에 대한 평가

초록

The purpose of this study was to compare the compression ratios of images obtained from three types of CR machines using the DICOM JPEG compression algorithm and to evaluate the visually lossless irreversible image compression ratio. Twenty chest PA images from each of the AGFA CR, Fuji CR, and Kodak CR systems were compressed with the JPEG Extended (1.2.840.10008.1.2.4.51) algorithm, which is the default transfer syntax for lossy JPEG 12-bit image compression. To control the JPEG compression ratio, the elements of the quantization matrix were adjusted linearly. To evaluate the visually lossless irreversible image compression ratio, five radiologists compared the original images with the compressed images for ten chest PA images obtained from each of the three CR systems. Each pair of original and compressed images was magnified 200% and selectively toggled by the observers. The mean compression ratios of the 12-bit AGFA CR and Kodak CR images changed similarly with variations in the quantization matrix, and showed less change than the 10-bit Fuji CR images. When the original and lossy-compressed images were magnified to 200%, the visually lossless thresholds were 12:1 for AGFA and Fuji CR images, and 13:1 for Kodak CR images. The compression ratio of images may vary depending on the type of CR system and is primarily influenced by the bit depth (bits per pixel) of the images. The visually lossless irreversible image compression threshold ranges from 12:1 to 13:1 and is acceptable for primary image interpretation.

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