How can I separate stuck regions in an image with Image Processing Toolbox?

Hi everybody,

I am working on image processing with Image Processing Toolbox, although it is not my major field of study! My case study is that, I filled a micro-rectangular channel with micro-sphere glass beads and then got the image from cross section of this channel (with X-ray) to study the structure of these glasses in container. You can find the obtained image in the following link: http://www2.picturepush.com/photo/a/8705500/img/8705500.png

After that, I applied the Canny edge detector to the above image to find where is the glass particles. See the outcome result in: http://www4.picturepush.com/photo/a/8705507/img/8705507.png

However, my problem is that, in some region that I indicated with red rectangular in above picture, some particles stick to each other and the edge detector considered them as a one!

I appreciate if someone could help me or give me some glue to figure it out, how I can separate them or how the algorithm should be to make the MATALB understand these regions contain more than one particle and subsequently separate them!

Thank you!