Abstract:

In this paper, two lossy compression methods have been used on the singleframe chest CT images, which belong to the DICOM standard. There are two experiments:1. Discrete Cosine Transformbased JPEG algorithm has been used on 50 singleframe chest CT images with different compression ratios.The compressed medical images are  compared with the original images by 3 radiologists. According to the result of the process, a Receiver Operating Characteristics analysis and a ttest are performed to ascertain the clinical performance. The conclusion is that the chest CT images with the compression ratios as high as 10:1 can be utilized without affecting the clinical diagnosis.2. Wavelet transformbased JPEG2000 algorithm has been used on the single frame chest CT images for lossy compressions.The compressed chest CT images still have the diagnostic value, when the compression ratio is less than 20:1.The result is  judged by the objective criteria fidelity.

Key words: JPEG;JPEG2000;DCT;wavelet transform;CT image;lossy compression;ROC;ttest