Set partitioning in hierarchical trees

Set partitioning in hierarchical trees (SPIHT) is an image compression algorithm that exploits the inherent similarities across the subbands in a wavelet decomposition of an image.

General description

The algorithm codes the most important wavelet transform coefficients first, and transmits the bits so that an increasingly refined copy of the original image can be obtained progressively. The SPIHT method is not a simple extension of traditional methods for image compression, and represents an important advance in the field. The method deserves special attention because it provides the following:

   good image quality, high PSNR, especially for color images;
   it is optimized for progressive image transmission;
   produces a fully embedded coded file;
   simple quantization algorithm;
   fast coding/decoding (nearly symmetric);
   has wide applications, completely adaptive;
   can be used for lossless compression.
   can code to exact bit rate or distortion;
   efficient combination with error protection.

Each of these properties is discussed below. Note that different compression methods were developed specifically to achieve at least one of those objectives. What makes SPIHT really outstanding is that it yields all those qualities simultaneously. So, if in the future you find one method that claims to be superior to SPIHT in one evaluation parameter (like PSNR), remember to see who wins in the remaining criteria

See also

• EZW