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The DCT Transform
Traditional JPEG compression uses the Discrete Cosine Transformation (DCT), which compresses an image in 8x8 blocks and results in visible artifacts at high compression rates. JPEG artifacts include visible seams at the tile edges, dubbed as "blocking artifacts".

The Wavelet Transform
The wavelet transform encodes an image in a continuous stream allowing it to avoid the artifacts that result from DCT's division of an image into discrete compression blocks. Wavelet artifacts take the form of blurring high contrast lines, merely making the image look softer. The wavelet transform performs what's called, multi-resolution compression-it stores image information in a series of bands, with the most important image information at the beginning of the file. Each band contains a representation of the entire image, with the various bands containing details of the image at every level, from coarse resolution and textures to fine details.

An inherent benefit of the wavelet's multi-resolution architecture, is the ability to progressively access the encoded image in a smooth continuous fashion without having to download, decode and/or print the entire file. Wavelet compressed images appear first as an image with coarse resolution and then finer resolution details are progressively filled in. Since the most important details are stored at the front of the image file, users will first see a blurry version of the image and the remaining details appearing as the bitstream arrives. Usually with about 10% of the image data, the user can tell what the image will be and can decide whether or not to wait for higher resolution. The current JPEG is single-resolution, so with 10% of the data, the user will have barely gotten a peek at the top of the image and has wait for the entire download.

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