italian site there is a little explanation of LCE system (for led model, but it should be the same for pdp).
It is the Micro-dimming!
They obtained technical charts from Samsung, but are not allowed to publish them.
I try to translate it, hope a little better than Google:
"The new technology is called Microdimming, and who knows Photoshop will have no difficult understanding what we're talking about. The Microdimming is a Local Contrast Enhancement filter. There was a similar filter in the past years TVs, but it analyzed the whole picture: it is like when we open a photo in Photoshop and we select "Adjust Curves" to adjust the tone on the high and low lights of the overall image.
This year, thanks to Microdimming, Samsung splits the image in 288 blocks and applies this procedure for each block, trying to maintain the same level of brightness on the border between a block and another. It is a software algorithm executed by CPU that seems to perform very well.
Things have gone even better for Americans, as they can boast the Microdimming Plus: this is nothing more than an additional chip on the card, missing in our TV (you can see the hole on the right), that is dedicated to this task. Being mostly derived from the processor chip used by Samsung on digital cameras, it offers much faster computational speed, more accuracy and most importantly less burdeness on the CPU thereby improving the whole image processing time (lower input lag). A choice that looks strange, though Samsung says that ultimately the differences are not so marked, and that the choice was made by Samsung Europe: the quality was already good even without the additional chip."
In other comments they confirmed that the number of blocks is certainly 288.