How to Draw a point in an image using given co-ordinate with python opencv?

Question

I have one image and one co-ordinate (X, Y). How to draw a point with this co-ordinate on the image. I want to use Python OpenCV.

Answer 1

You can use cv2.circle() function opencv module:

image = cv.circle(image, centerOfCircle, radius, color, thickness) 

Keep radius as 0 for plotting a single point and thickness as a negative number for filled circle

import cv2 image = cv2.circle(image, (x,y), radius=0, color=(0, 0, 255), thickness=-1) 

Answer 2

I'm learning the Python bindings to OpenCV too. Here's one way:

#!/usr/local/bin/python3 import cv2 import numpy as np  w=40 h=20 # Make empty black image image=np.zeros((h,w,3),np.uint8)  # Fill left half with yellow image[:,0:int(w/2)]=(0,255,255)  # Fill right half with blue image[:,int(w/2):w]=(255,0,0)  # Create a named colour red = [0,0,255]  # Change one pixel image[10,5]=red  # Save cv2.imwrite("result.png",image) 

Here's the result - enlarged so you can see it.

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Here's the very concise, but less fun, answer:

#!/usr/local/bin/python3 import cv2 import numpy as np  # Make empty black image image=np.zeros((20,40,3),np.uint8)  # Make one pixel red image[10,5]=[0,0,255]  # Save cv2.imwrite("result.png",image)