Monday, 22 August 2016

TUT11: Let's draw the OpenCV logo

Hello guys,
In this tutorial, we are going to see how to make a logo of OpenCV. Before starting I would like you to try to make logo yourself. You can make logo of some other things like brands or anthing you like.

Here's the code

import cv2
import numpy as np

img=np.zeros((500,500,3), np.uint8)

cv2.ellipse(img, (250,100), (70,70), 135, 0, 270, (0,0,255),50)
cv2.ellipse(img, (150,280), (70,70), 10, 0, 270, (0,255,0),50)
cv2.ellipse(img, (350,280), (70,70), 315, 0, 270, (255,0,0),50)

cv2.putText(img,'OpenCV',(75,450), font, 3,(255,255,255),2,cv2.LINE_AA)



Line1-2 : Import necessary packages cv2 and numpy

Line 3 : Create a canvas using np.zeros()

Line 4-6 : Create an ellipse using ellipse function provided by OpenCV. The parameters of ellipse are                  as follows:
                   1) Image or canvas
                   2) Center
                   3) Half of the size of the ellipse main axes a and b given as (a, b).
                   4) Ellipse rotation angle in degrees.
                   5) Starting angle of the ellipse arc in degrees
                   6) Ending angle of the ellipse arc in degrees.
                   7) color
                   8) thickness

                For more info on ellipse(), click here.

Line 7 : Specify the font as hershey_simplex. You can try other fonts too here

Line 8 : If you read the previous tutorial, you may be familiar with putText() finction. It puts                            whatever text you want to write on canvas. Click here if you do not know how putText()

Line 9 : Displays the image 

Line 10 : Holds screen indefinitely until user closes the window

Line 11 : Closes any open windows.


For any queries, Please ask in comment section below.


  1. i'm not understanding the angle 10,135,315

    1. That argument is the angle between the horizontal axis(of the image) and the major axis of the ellipse in clockwise direction.