[FIXED] How do I crop the solar panels captured by drone?

Issue

I am currently working on solar panel cropping from the images taken by the drone(attaching sample image). I have tried using contours but there wasn't a proper outcome. It was not detecting all solar panels in the image some of them were missing. I struck here itself. How do I proceed further? Please help me with this problem.

Thank you,

Sample Code:

import cv2
import numpy as np
img = cv2.imread('D:\\SolarPanel Images\\solarpanel.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
edges = cv2.Canny(blur,100,200)    
th3 = cv2.adaptiveThreshold(edges,255,cv2.ADAPTIVE_THRESH_GAUSSIAN_C,cv2.THRESH_BINARY,11,2)

im2, contours, hierarchy = cv2.findContours(th3, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
print("Len of contours",len(contours)
try: hierarchy = hierarchy[0]
except: hierarchy = []

height, width,  = edges.shape
min_x, min_y = width, height
max_x = max_y = 0

# computes the bounding box for the contour, and draws it on the image,
for contour, hier in zip(contours, hierarchy):
    area = cv2.contourArea(contour)

    if area > 10000 and area < 250000:
        (x,y,w,h) = cv2.boundingRect(contour)
        min_x, max_x = min(x, min_x), max(x+w, max_x)
        min_y, max_y = min(y, min_y), max(y+h, max_y)
        if w > 80 and h > 80:
            cv2.rectangle(img, (x,y), (x+w,y+h), (255, 0, 0), 2)

            cv2.imshow('cont imge', img)
            cv2.waitKey(0)

Solution

To find contours in images where the object of importance is clearly distinguishable from the background, you can always try converting the image to HSV format and then contour. I did the following:

import cv2
import numpy as np
img = cv2.imread('panel.jpg')
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV) 
ret,thresh1 = cv2.threshold(hsv[:,:,0],100,255,cv2.THRESH_BINARY)
im2, contours, hierarchy = cv2.findContours(thresh1, cv2.RETR_TREE, 
cv2.CHAIN_APPROX_SIMPLE)
try: hierarchy = hierarchy[0]
except: hierarchy = []
for contour, hier in zip(contours, hierarchy):
    area = cv2.contourArea(contour)
    if area > 10000 and area < 250000:
       rect = cv2.minAreaRect(contour)
       box = cv2.boxPoints(rect)
       box = np.int0(box)
       cv2.drawContours(img,[box],0,(0,0,255),2)
       cv2.imshow('cont imge', img)
       cv2.waitKey(0)
cv2.imwrite("result.jpg",img)

Result:

Answered By - janu777