如何使用 Canny 邊緣檢測去除背景

Question

我想刪除背景並銳化以下類型的圖像：圖像 1

這兩個都是簽名。 我希望能夠刪除除簽名本身之外的所有內容並銳化簽名行。 我可以使用以下代碼使用 Canny 邊緣檢測來獲得掩碼

import cv2
im_path  = r'test2.png'
image = cv2.imread(im_path) #args["image"]
image = cv2.resize(image, (680, 460))
#rgb = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]

cv2.imshow('thresh', thresh) ###for showing 

cv2.imwrite('thresh.jpg', thresh) ###for saving
cv2.waitKey()

這些是我得到的面具；

但我對接下來要執行的圖像處理操作一無所知。

PS：這些簽名是相同的（不是偽造的），下一步是找出它們之間的相似性。

Answer 1

嘗試這個

import cv2
import numpy as np

image = cv2.imread("r'test2.png'")
original = image.copy()
mask = np.zeros(image.shape, dtype=np.uint8)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (5,5))
opening = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=3)

cnts = cv2.findContours(opening, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
cnts = sorted(cnts, key=cv2.contourArea, reverse=True)
for c in cnts:
    cv2.drawContours(mask, [c], -1, (255,255,255), -1)
    break

close = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel, iterations=4)
close = cv2.cvtColor(close, cv2.COLOR_BGR2GRAY)
result = cv2.bitwise_and(original, original, mask=close)
result[close==0] = (255,255,255)

cv2.imshow('result', result)
cv2.waitKey()