How to get the edge of a pile of white dots?

I v transferred a picture into b&w and it now looks like a pile of white dots with black background.

How can i get the specific area of there dots, and show the whole area in white color from this picture?

Answer 1

[Walter Roberson]

regionprops( double(BW), 'Area')

The purpose of the double() there is to prevent BW from being a logical matrix, because if BW is a logical matrix then regionprops() will automatically do an object labeling, whereas you just want the total (I guess?) Or if you want clusters to be analyzed then

regionprops( logical(BW), 'Area')

and that will return a structure array that you can later total the areas of.

Answer 2

[Image Analyst]

See my BlobsDemo image segmentation tutorial. It does that. http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862