bwboundaries and polyshape for microstructural image processing

Hi there,

I used the matlab function bwboundaries to find grain boundaries in my microstructural image which generates a binary image as shown on the left. I then tried to represent each grain with a polygon using the polyshape function, which generates the image on the right. However, as you can see, the polygons generated around the smaller grains (near the top and bottom regions) doesn't look right. These grains appear to be embedded in a much larger grain which is not the case. I'm thinking this could be due to the grains being very small in size which affected the polygon population. Does anyone have any idea on how to improve the generation of the polygons?

Thank you.

Best Regards,

Wayne