[L,Ne]=bwlabel(bw2);

This line of code uses the function bwlabel to label connected components in a binary image. The input argument bw2 is the binary image to be labeled. The output arguments L and Ne are the labeled image and the number of connected components, respectively.

L is a matrix of the same size as bw2, where each pixel is assigned a label that corresponds to the connected component it belongs to. The background pixels are labeled 0.

Ne is an integer that represents the total number of connected components in the binary image.