import cv2

img = cv2.imread('a1.jpg')
mser = cv2.MSER_create()

#Resize the image so that MSER can work better
img = cv2.resize(img, (img.shape[1]*2, img.shape[0]*2))

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
vis = img.copy()

regions = mser.detectRegions(gray)
hulls = [cv2.convexHull(p.reshape(-1, 1, 2)) for p in regions[0]]
cv2.polylines(vis, hulls, 1, (0,255,0))

cv2.imshow('img',vis)
cv2.waitKey(0)
cv2.destroyAllWindows()