利用python3和opencv去掉图片黑边

可以通过以下步骤使用Python和OpenCV去掉图片的黑边：

1. 导入必要的库

import cv2
import numpy as np

2. 读取图片

img = cv2.imread('image.jpg')

3. 将图片灰度化

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

4. 对图片进行二值化处理

thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]

5. 查找图片边缘

cnts = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]

6. 找到图片最大的边缘

c = max(cnts, key=cv2.contourArea)

7. 获取最大边缘的坐标范围

x,y,w,h = cv2.boundingRect(c)

8. 截取去掉黑边的图片

crop = img[y:y+h, x:x+w]

9. 显示截取后的图片

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

完整代码如下：

import cv2
import numpy as np

img = cv2.imread('image.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV + cv2.THRESH_OTSU)[1]
cnts = cv2.findContours(thresh, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cnts = cnts[0] if len(cnts) == 2 else cnts[1]
c = max(cnts, key=cv2.contourArea)
x,y,w,h = cv2.boundingRect(c)
crop = img[y:y+h, x:x+w]
cv2.imshow('crop', crop)
cv2.waitKey()