How do i remove the background from this image, just want the lettuce from the picture?

Question

Just want to retain the lettuce, I have hundreds of image like this and would be comparing the size of lettuce, so to began with I tried the canny edge detection but it doesn't seems to work, any idea how shall move ahead with this

Answer 1

You can convert the RGB image into HSV image and segment the Green color region.

import cv2
import numpy as np

frame=cv2.imread('a.png')
hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

lower = np.array([50,50,50])
upper = np.array([70,255,255])

mask = cv2.inRange(hsv, lower, upper)
res = cv2.bitwise_and(frame,frame, mask= mask)

cv2.imshow('frame',frame)
cv2.imshow('res',res)
cv2.waitKey(0)
cv2.destroyAllWindows()