OpenCV get pixels on an ellipse-CodePudding

I'm new to OpenCV and I'm trying to get the pixels of an ellipse from an image.

For example, I draw an ellipse on a random image (sample geeksforgeeks code):

import cv2
path = r'C:\Users\Rajnish\Desktop\geeksforgeeks\geeks.png'
image = cv2.imread(path)
window_name = 'Image'
center_coordinates = (120, 100)
axesLength = (100, 50)
angle = 0
startAngle = 0
endAngle = 360
color = (0, 0, 255)
thickness = 5
image = cv2.ellipse(image, center_coordinates, axesLength,
           angle, startAngle, endAngle, color, thickness)
cv2.imshow(window_name, image)

It gives output like below:

Now, I want to get the pixel value of boundary line of ellipse. If it is possible I would like to get the pixel of ellipse using cv2.ellipse() back as an array of coordinates.
Can anyone help me with this please.

CodePudding user response：

There is no direct OpenCV way probably to get these points of the ellipse but you can extract your points via indirect way like this:

mask = cv2.inRange(image, np.array(color), np.array(color))
contour = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)[-2][0]

contour will store the outer points of your red ellipse. Here, what I have done is created a mask image of the ellipse and found the externalmost contour's points that is the required thing.