What is 'level' value in cvPyrSegmentation() in OpenCV?

I'm trying to find connected components using the Pyramid Segmentation function in OpenCV and VC++. What should I put as the level of the pyramid? Please explain (I've tried to make sense of the 开发者_开发知识库O'Reilly book)

From here: level – Maximum level of the pyramid for the segmentation.
This means that the maximum value that level can get is the log-2 of the the minimum of the image width and height.
Realistically, you would reduce it by at least 2 or 3 as 4x4 or 8x8 images are typically not very informative...