Salaam-E-Llama

Today, I get to learn about Lloyd-Max quantizers!

Quantization is the conversion of continuous output into discrete output by selecting a set of possible discrete output values, and rounding or truncating each actual value to one of the values in that set. (Mrs. Francon, please correct me if I'm wrong, since you're the quantization expert :-)).

Quantization is used in analog-to-digital signal conversion, and it is also used in image compression to achieve higher compression. Most image compression algorithms exploit statistical redundancy - pixels in an image usually have similar intensities to the surrounding pixels. And many pixels in the image have the same intensity.

Psychovisual redundancy takes this one step further - if the pixels with similar intensities in the image can all be replaced by pixels with one intensity (maybe the median of all the original intensities), and the change is subtle enough that it won't make much difference to the human eye, then much higher compression can be achieved. So, quantization is sometimes used to take the whole spectrum of pixel intensities in the image and replace it by a few representative pixel intensities. Interesting, eh?

I am very happy indeed, because my dad comes home today, and because I got to spend some time with my fiancee yesterday, the most wonderful llama on the Earth. And it's been raining for the past few days, which is always nice. Makes it feel like fall.