What is the difference between lossy and lossless compression?
Encoding an image is a process that converts a raw image (e.g., the original radiograph) into a more compact coded file. Decoding converts the coded file to a decoded image. If the raw image and the decoded image are the same, the compression method is considered lossless. If there is a difference between the raw image and the decoded image, the method of encoding and decoding is considered lossy. Lossless compression can usually achieve ratios of 2 : 1 or 3 : 1. Lossy compression can achieve much higher compression ratios; however, overcompression may destroy fine detail, making the image unacceptable for diagnostic purposes.