How to Compute the Morphological Gradient of an Image Using OpenCV in Python?

Morphological gradient is a useful technique for image processing tasks, which can be used to detect the edges and boundaries of objects in an image. In this article, we will discuss how to compute the morphological gradient of an image using OpenCV in Python.

Understanding Morphological Gradient

Morphological gradient is a mathematical operation that can be applied to an image to enhance edges and boundaries of objects. It is useful for tasks such as object detection, segmentation, and feature extraction.

The morphological gradient of an image is obtained by the difference between its dilation and erosion. The dilation operation enlarges the bright regions of an image, whereas erosion reduces them. The difference between these two operations will highlight the edges and boundaries of objects, creating a gradient image.

In OpenCV, the morphological gradient can be computed using the cv2.morphologyEx() function. Let’s take a look at an example.

Example: Computing Morphological Gradient of an Image

In this example, we will load an image and compute its morphological gradient using OpenCV and Python. Here’s the code:

import cv2
import numpy as np

# Load the image
img = cv2.imread('image.jpg', 0)

# Define the kernel for morphological operation
kernel = np.ones((5,5), np.uint8)

# Compute the morphological gradient
gradient = cv2.morphologyEx(img, cv2.MORPH_GRADIENT, kernel)

# Display the original and gradient image
cv2.imshow('Original Image', img)
cv2.imshow('Gradient Image', gradient)
cv2.waitKey(0)
cv2.destroyAllWindows()

In this code, we first load an image using the cv2.imread() function. We then define a 5×5 kernel using the np.ones() function; this kernel will be used for the morphological operation. We then compute the morphological gradient of the image using the cv2.morphologyEx() function, with the cv2.MORPH_GRADIENT flag. Finally, we display the original and gradient image using the cv2.imshow() function.

Conclusion

In this article, we discussed how to compute the morphological gradient of an image using OpenCV in Python. We explained the concept of morphological gradient and provided an example of how to use the cv2.morphologyEx() function to compute it. With this knowledge, you can apply morphological gradient to your own image processing tasks in Python.