Pada kesempatan ini kita ingin mendeteksi sebuah bentuk kotak dari sebuah contoh image. Download image berikut dan simpan dalam direktori D:\Project\Latihan

buatlah sebuah kode sederhana berikut ini dan simpan dalam nama shape.py.

# Sumber https://pythontips.com/2015/03/11/a-guide-to-finding-books-in-images-using-python-and-opencv/
# import the necessary packages
import numpy as np
import cv2

# load the image, di ubah ke grayscale
image = cv2.imread("example.jpg")
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray = cv2.GaussianBlur(gray, (3, 3), 0)
#cv2.imshow("Gray", gray)

# Deteksi Tepi
edged = cv2.Canny(gray, 10, 250)
#cv2.imshow("Edged", edged)

# construct and apply a closing kernel to 'close' gaps between 'white'
# pixels
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (7, 7))
closed = cv2.morphologyEx(edged, cv2.MORPH_CLOSE, kernel)
#cv2.imshow("Closed", closed)


# find contours (i.e. the 'outlines') in the image and initialize the
# total number of books found
(cnts, _) = cv2.findContours(closed.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
total = 0

# Looping dalam contours
for c in cnts:
	# approximate the contour
	peri = cv2.arcLength(c, True)
	approx = cv2.approxPolyDP(c, 0.02 * peri, True)

	# if the approximated contour has four points, then assume that the
	# contour is a book -- a book is a rectangle and thus has four vertices
	if len(approx) == 4:
		cv2.drawContours(image, [approx], -1, (0, 255, 0), 4)
		total += 1

# Menampilkan hasil
print ("Terdapat gambar buku sejumlah : ".format(total))
cv2.imshow("Output", image)
cv2.waitKey(0)

Jalankan dengan perintah python shape.py, akan didapatkan hasil seperti berikut ini

di command promp akan ditampilkan “Terdapat gambar buku sejumlah : 4“