What kind of post-processing (connected component, morphological operator, etc.) can be applied to obtain the most similar segmentation to ground truth?

Hi,

I have applied my algorithm and the output of segmentation is the left image as follows:

I have to do post-processing to the left image, to increase the similarity to the ground truth (right figure). My question is what kind of post-processing can be applied on the left figure? what kind of morphological operators and which structure element can be used to this aim? I tried some of them, but quite confusing. Can you please help me? or is there any function or code that I can use? Thanks