Image Quantization help. dwt2 and quantization.

I have converted an image to cieLab version from RGB image, then split them all up into L, A and B form. Next, I applied dwt2() to the image so now i have lCA, lCV, lCH and lCD, a total of 12 "variables" for L, A and B. from the image, I have gathered the necessary max and min and they vary from -90.5 to 170.xxx. All the values are of awkward ranges and I want to quantize them. How do I quantize (group or rounding up and down) such values?

Each "variable" has 200 x 200 values inside.Example: 120.34 will be converted to 120 or something. This is so that I can get the probability of the value to be in the range.

Please help. Thank you.