before image
https://imgur.com/f190UFk
processed image
https://imgur.com/JkEhWkS
you can see the "processed image" has highlight, so the transform works bad.
any possible to make an rectangle that ignore that highlight area?
import os
import cv2
import numpy as np
from nanoid import generate
def processImage(imagepath, ext):
img = cv2.imread(imagepath)
hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
h, s, v = cv2.split(hsv)
# _, threshed = cv2.threshold(s, 50, 255, cv2.THRESH_BINARY_INV)
_, threshed = cv2.threshold(s, 50, 255, cv2.THRESH_BINARY_INV)
# cnts = cv2.findContours(threshed, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2]
cnts = cv2.findContours(threshed, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2]
canvas = img.copy()
#cv2.drawContours(canvas, cnts, -1, (0, 255, 0), 1)
cnts = sorted(cnts, key = cv2.contourArea)
cnt = cnts[-1]
print(cnt)
arclen = cv2.arcLength(cnt, True)
approx = cv2.approxPolyDP(cnt, 0.005 * arclen, True)
cv2.drawContours(canvas, [cnt], -1, (255, 0, 0), 5, cv2.LINE_AA)
cv2.drawContours(canvas, [approx], -1, (0, 0, 255), 1, cv2.LINE_AA)
print(approx)
approx = rectify(approx)
pts2 = np.float32([[0, 0], [2480, 0], [2480, 3508], [0, 3508]])
M = cv2.getPerspectiveTransform(approx, pts2)
dst = cv2.warpPerspective(canvas, M, (2480, 3508))
filename_output = generate() + ext
cv2.imwrite('./static/' + filename_output, dst)
topLeft, topRight, bottomRight, bottomLeft = approx
topLeft = topLeft.tolist()
topRight = topRight.tolist()
bottomRight = bottomRight.tolist()
bottomLeft = bottomLeft.tolist()
return {
'filename': './static/' + filename_output,
'shape': img.shape,
'approx': {
'topLeft': topLeft,
'topRight': topLeft,
'bottomRight': bottomRight,
'bottomLeft': bottomLeft,
},
}
def rectify(h):
h = h.reshape((13, 2))
hnew = np.zeros((4, 2), dtype = np.float32)
add = h.sum(1)
hnew[0] = h[np.argmin(add)]
hnew[2] = h[np.argmax(add)]
diff = np.diff(h, axis = 1)
hnew[1] = h[np.argmin(diff)]
hnew[3] = h[np.argmax(diff)]
return hnew
