I'm attempting to accurately get the contour of the bounding box around the comic book cover in the attached example images.
This is the code that I currently have.
from pyimagesearch import imutils
from skimage import exposure
import numpy as np
import argparse
import cv2
ap = argparse.ArgumentParser()
ap.add_argument("-q", "--query", required = True,
help = "Path to the query image")
args = vars(ap.parse_args())
print(args["query"])
# load the query image, compute the ratio of the old height
# to the new height, clone it, and resize it
image = cv2.imread(args["query"])
ratio = image.shape[0] / 300.0
orig = image.copy()
image = imutils.resize(image, height = 300)
# convert the image to grayscale, blur it, and find edges
# in the image
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray = cv2.bilateralFilter(gray, 11, 17, 17)
edged = cv2.Canny(gray, 30, 200)
#find contours in the edged image, keep only the largest
# ones, and initialize our screen contour
cnts = cv2.findContours(edged.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
cnts = imutils.grab_contours(cnts)
cnts = sorted(cnts, key = cv2.contourArea, reverse = True)[:4]
screenCnt = None
# loop over our contours
rect_cnts = []
for c in cnts:
peri = cv2.arcLength(c, True)
approx = cv2.approxPolyDP(c, 0.04 * peri, True)
if len(approx) == 4: # shape filtering condition
screenCnt = approx
break
print(screenCnt)
cv2.drawContours(image, [screenCnt], -1, (0, 255, 0), 3)
cv2.imshow("Book Image", image)
cv2.waitKey(0)
The problem arises when I try to do the shape filtering.
rect_cnts = []
for c in cnts:
peri = cv2.arcLength(c, True)
approx = cv2.approxPolyDP(c, 0.04 * peri, True)
if len(approx) == 4: # shape filtering condition
screenCnt = approx
break
It appears as if the contours returned are not qualifying as a rectangle. I'm not sure how to fine-tune this so that the contour is better. These are the results I'm currently getting.
