cv2.cv for Python 2.7 32 bit in an OpenCV sample code

Question

I am trying to understand how edge detection works and was trying the code from OpenCV below on Py 2.7, 32 bit:

import cv2
import numpy as np
from matplotlib import pyplot as plt
img = cv2.imread('SiliconPost.jpeg',0)
laplacian = cv2.Laplacian(img,cv2.CV)
sobelx = cv2.Sobel(img,cv2.CV,1,0,ksize=5)
sobely = cv2.Sobel(img,cv2.CV,0,1,ksize=5)
plt.subplot(2,2,1),plt.imshow(img,cmap = 'gray')
plt.title('Original'), plt.xticks([]), plt.yticks([])
plt.subplot(2,2,2),plt.imshow(laplacian,cmap = 'gray')
plt.title('Laplacian'), plt.xticks([]), plt.yticks([])
plt.subplot(2,2,3),plt.imshow(sobelx,cmap = 'gray')
plt.title('Sobel X'), plt.xticks([]), plt.yticks([])
plt.subplot(2,2,4),plt.imshow(sobely,cmap = 'gray')
plt.title('Sobel Y'), plt.xticks([]), plt.yticks([])
plt.show()

But I keep coming across an error: AttributeError: 'module' object has no attribute 'CV'

How do I go about rectifying this error?

• KelvinS: Did you import cv2? Is OpenCV properly installed? Try to run help(cv2) to see what happens. Note: post the code you are trying to run in the question, not the link.
• DS2019: Yes, I did import cv2, but I might have messed up the installation. Let me try help(cv2).
• DS2019: @KelvinS, I shall post the code right away. Thank you!
• DS2019: @KelvinS I am getting the error NameError: name 'cv2' is not defined. Does this mean that OpenCV is not installed correctly?
• DS2019: @KelvinS, actually, I took out .CV on a hunch and it worked. It gives another error now: TypeError: an integer is required.

Answer 1

From the documentation, ddepth is the second parameter which defines the depth of the output image and is of type int.

What you passed to it; cv2.CV, is nothing. I believe its a typo and you meant to type either cv2.CV_64F or cv2.CV_16S or something along these lines.

Refer back to your tutorial to see what was used but you are looking for something along those lines.

Side Note: CV_16S, CV_64F etc are default variables in OpenCV of type int. You can see this from their implementation.

• DS2019: It did for sure! Thank you!