Element sizes in segmentmesher

Hello all,
I am using the segmentmesher to create a volumetric mesh. However, the generated meshes do not look fine to me; at some parts the mesh is coarse and at some parts, it is very fine. I tried to play with segmentmesher parameters to solve that however, I was not successful. I attached a picture from my current mesh.

How should I solve this problem?
Any helps on this is greatly appreciated.