Image processing for the particle size and shape

If someone has given me this image http://jcp.bmj.com/content/62/6/481/F6.large.jpg , how can I measure the particle size and colour of any particle?

Answer 1

[Image Analyst]

Which particles? Black? White? Just pick a color channel, threshold, and call regionprops() as shown in my Image Segmentation Tutorial, BlobsDemo: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862