opencv_python 边缘检测笔记（Sobel，Scharr，Laplacian，Canny）

分手后的思念是犯贱 2023-05-29 05:08 140阅读 0赞

# opencv\_python 边缘检测笔记（Sobel，Scharr，Laplacian，Canny） #

![在这里插入图片描述][20191104141709100.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][20191104141756496.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 1]

梯度和方向![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 2]  
非极大值抑制：  
当中心点C>(dTmp1 && dTmp2)时，保留  
当中心点C<(dTmp1 || dTmp2)时，非极大值抑制  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 3]  
当A>(C&&B)时，保留  
当A<(C||B)时，非极大值抑制  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 4]  
保留潜在边缘  
![在这里插入图片描述][20191104141940902.png]  
代码实现：

import cv2
    import numpy as np
    
    img = cv2.imread("img/lena.jpg", 0)
    # canny边缘检测
    canny = cv2.Canny(img, 50, 100)
    # Sobel算子
    sobelx = cv2.Sobel(img, cv2.CV_64F, dx=1, dy=0, ksize=3)
    sobelx = cv2.convertScaleAbs(sobelx)
    sobely = cv2.Sobel(img, cv2.CV_64F, dx=0, dy=1, ksize=3)
    sobely = cv2.convertScaleAbs(sobely)
    sobelxy = cv2.addWeighted(sobelx, 0.5, sobely, 0.5, 0)
    # Schar算子
    scharrx = cv2.Scharr(img, cv2.CV_64F, dx=1, dy=0)
    scharrx = cv2.convertScaleAbs(scharrx)
    scharry = cv2.Scharr(img, cv2.CV_64F, dx=0, dy=1)
    scharry = cv2.convertScaleAbs(scharry)
    scharrxy = cv2.addWeighted(scharrx, 0.5, scharry, 0.5, 0)
    # Laplacian算子
    laplacian = cv2.Laplacian(img, cv2.CV_64F)
    laplacian = cv2.convertScaleAbs(laplacian)
    
    cv2.imshow('canny', canny)
    cv2.imshow('Sobel', sobelxy)
    cv2.imshow('scharr', scharrxy)
    cv2.imshow('laplacian', laplacian)
    cv2.waitKey(0)
    cv2.destroyAllWindows()

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 5]

### 参考视频： ###

https://www.bilibili.com/video/av61678672/?p=6

[20191104141709100.png]: https://img-blog.csdnimg.cn/20191104141709100.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191104141716615.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70
[20191104141756496.png]: https://img-blog.csdnimg.cn/20191104141756496.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191104141816379.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20191104141832272.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20191104141903446.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20191104141923348.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70
[20191104141940902.png]: https://img-blog.csdnimg.cn/20191104141940902.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy_size_16_color_FFFFFF_t_70 5]: https://img-blog.csdnimg.cn/20191105120056523.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzNTYyOTgy,size_16,color_FFFFFF,t_70