Life2Coding
Create a Black Background Image using OpenCV in Python

This post will be helpful in learning OpenCV using Python programming. Here I will show how to implement OpenCV functions and apply them in various aspects using some great examples. Then the output will be visualized along with the comparisons.

We will also discuss the basic of image processing and provide the detail explanation related to the OpenCV functions.

Requirements:

First, you need to setup your Python Environment with OpenCV. You can easily do it by following Life2Coding’s tutorial on YouTube: Linking OpenCV with Python 3

Goals:

The goal is to make you understand how to create a black background image using OpenCV

Documentation:

imshow()

None=cv.imshow(winname, mat)

Displays an image in the specified window.

Parameters
winname Name of the window.
mat Image to be shown.

waitKey()

retval=cv.waitKey([, delay])

Waits for a pressed key.

Parameters
delay Delay in milliseconds. 0 is the special value that means “forever”.

destroyAllWindows()

None=cv.destroyAllWindows()

Destroys all of the HighGUI windows.

Steps:

  • Create a numpy image using np.zeros()
  • Display all the images using cv2.imshow()
  • Wait for keyboard button press using cv2.waitKey()
  • Exit window and destroy all windows using cv2.destroyAllWindows()

Example Code:

import numpy as np
import cv2
my_img_1 = np.zeros((512, 512, 1), dtype = "uint8")
cv2.imshow('Single Channel Window', my_img_1)

my_img_3 = np.zeros((512, 512, 3), dtype = "uint8")
cv2.imshow('3 Channel Window', my_img_3)

cv2.waitKey(0)
cv2.destroyAllWindows()

Output:

5cb3caeea17ab Create a Black Background Image using OpenCV in Python
life2coding_icon [] Create a Black Background Image using OpenCV in Python

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