Canny Edge Detection in OpenCV Python

canny_edge_detection_in_opencv.py

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread("lena.jpg")
img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
canny = cv2.Canny(img, 100, 200)

titles = ['image', 'canny']
images = [img, canny]
for i in range(2):
    plt.subplot(1, 2, i+1), plt.imshow(images[i], 'gray')
    plt.title(titles[i])
    plt.xticks([]),plt.yticks([])

plt.show()

image_gradients_and_canny_edge_detection.py

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread("messi5.jpg", cv2.IMREAD_GRAYSCALE)
lap = cv2.Laplacian(img, cv2.CV_64F, ksize=3)
lap = np.uint8(np.absolute(lap))
sobelX = cv2.Sobel(img, cv2.CV_64F, 1, 0)
sobelY = cv2.Sobel(img, cv2.CV_64F, 0, 1)
edges = cv2.Canny(img,100,200)

sobelX = np.uint8(np.absolute(sobelX))
sobelY = np.uint8(np.absolute(sobelY))

sobelCombined = cv2.bitwise_or(sobelX, sobelY)

titles = ['image', 'Laplacian', 'sobelX', 'sobelY', 'sobelCombined', 'Canny']
images = [img, lap, sobelX, sobelY, sobelCombined, edges]
for i in range(6):
    plt.subplot(2, 3, i+1), plt.imshow(images[i], 'gray')
    plt.title(titles[i])
    plt.xticks([]),plt.yticks([])

plt.show()

import cv2
import numpy as np
from matplotlib import pyplot as plt
def nothing(i):
pass

cv2.namedWindow("image")
cv2.createTrackbar('x',"image",0,100,nothing)
cv2.createTrackbar('y',"image",0,100,nothing)
while(True):
img = cv2.imread("lena.jpg")
x=cv2.getTrackbarPos('x',"image")
y=cv2.getTrackbarPos('y',"image")
canny= cv2.Canny(img,x,y)

cv2.imshow("image",img)
cv2.imshow("image",canny)
k=cv2.waitKey(0)
if(k==27):
    break

cv2.destroyAllWindows()
bro its not working bro can you please help me bro

Mr nagasrisai,
I tested your code and found out that the error lies in this line k=cv2.waitkey(0)
If you change it and write k=cv2.waitkey(1) , it will work well

nice

Can you please help me with code for video data, to find edges of the extracted frames then subtracting the frames from the centered frame and hence save it into a directory?