Code

import cv2
import numpy as np

def getContours(resized):
    contours, hierarchy = cv2.findContours(resized, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
    for cnt in contours:
        area = cv2.contourArea(cnt)
        print(area)
        if area > 5:
            cv2.drawContours(imgContour, cnt, -1,(255,0,0), 3)
            peri = cv2.arcLength(cnt,True)
            print(peri)
            approx = cv2.approxPolyDP(cnt, 0.02*peri, True)
            objCor = len(approx)
            x, y, w, h = cv2.boundingRect(approx)
            cv2.rectangle(imgContour, (x,y), (x+w, y+h), (0, 255, 0), 2)

            if objCor == 4: ObjectType = "Pan"
            else: ObjectType="None"
            cv2.putText(imgContour, ObjectType,(x+(w//2)-10, y+(h//2)-10), cv2.FONT_HERSHEY_COMPLEX, 0.25,(0,0,0),1)


path = r'C:\Users\Polo\Desktop\Python\Dakpannen\dakpannen4.jpg'
img = cv2.imread(path)

scale_percent = 300 # percent of original size
width = int(img.shape[1] * scale_percent / 100)
height = int(img.shape[0] * scale_percent / 100)
dim = (width, height)

resized = cv2.resize(img, dim, interpolation = cv2.INTER_AREA)

imgGray = cv2.cvtColor(resized, cv2.COLOR_BGR2GRAY)
imgBlur = cv2.GaussianBlur(imgGray, (7,7), 1)
imgCanny = cv2.Canny(imgBlur, 25,25)
imgContour = imgGray.copy()
getContours(imgCanny)

cv2.imshow('', imgContour)
cv2.waitKey(0)