Understanding JPEG-LS's regions

I am struggli开发者_运维知识库ng to understand what regions are in JPEG-LS.

I am reading it from wikipedia:

Each one of the differences found in the above equation is then quantized into roughly equiprobable and connected regions. For JPEG-LS, the differences g1, g2, and g3 are quantized into 9 regions and the region are indexed from -4 to 4

Quoting from here.

What are these regions? How they are calculated?

"To complete the definition of the contexts in LOCO-I, it remains to specify the values of the boundaries between quantization regions. For an 8-bit per pixel alphabet, the quantization regions for gj; j = 1;2;3; are {0}, {1; 2}, {3; 4; 5; 6}, {7; 8;...; 14}, {e|e>=15}, and their corresponding negative counterparts."

Found in http://www.hpl.hp.com/loco/dcc96copy.pdf

M. Weinberger, G. Seroussi, G. Sapiro, "LOCO-I: A Low Complexity, Context-Based, Lossless Image Compression Algorithm," Proc. IEEE Data Compression Conference, Snowbird, Utah, March-April 1996.