Image Processing With Python: A Guide To Edge Detection

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Consider yourself a software engineer engaged in a project that calls for detecting image edges. Opening an image in Opencv is the first step, and the image’s boundaries must be established next. In instances like this, edge detection is helpful.

Laplacian of Gaussian (LoG) and Canny are two of the techniques offered by Opencv for identifying an image’s edges. We will demonstrate how to apply each of these techniques in this article.

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Why Use Opencv And What Is Edge Detection?

An image processing method called edge detection aids in locating the edges of objects in a picture. Why is this crucial? Because determining the edges of objects in an image allows us better to understand the shapes and structures of those objects.

Opencv and python

Opencv is a powerful open-source software that allows you to perform edge detection on images efficiently. With just a few clicks, you can be on your way to understanding the shapes and structures of the objects in your images.

Understanding The Techniques Used In Edge Detection

Edge detection is a popular technique used in image processing and computer vision. It is used to determine the boundaries of objects in an image. There are several ways to perform edge detection, but the Sobel operator is one of the most popular methods.

We’ll demonstrate how to use Python’s Sobel operator along with Opencv in this tutorial. Additionally, we’ll demonstrate how to use edge detection on a live video stream.

Installing The Opencv Package After Downloading It

The Opencv package must be downloaded first. It is available for download and is a relatively small file on the GitHub page. After it’s finished, install it in the usual way.

Once you’ve installed it, open up your terminal and type in “opencv”. This will open up the primary interface for the package.

Exploring Opencv’s Edge Detection Capabilities

If you were wondering what edge detection is capable of in Opencv, this could be your ticket to more advanced image processing. The edges of objects in photos can be located via edge detection. And by using the appropriate parameters, you can easily identify the various features of an image quickly and accurately.

Edge detection

To begin your exploration of edge detection with Opencv, you’ll need to install it on your machine. You can do this by setting up the environment variables from the official website or downloading and installing the latest version from GitHub. Once installed, start the application and go to “Edge Detection” from the main menu.

Here you’ll have access to various options to adjust saturation, contrast, blur level, etc. Explore these settings until you find what works best for your images. Finally, click “Run Detection” at the bottom right corner to use edge detection algorithms and get those stunning results!

Implementing Edge Detection Using Python

Now that we have all the necessary components let’s discuss how to implement edge detection using Python. This process consists of several steps:

Edge detection with python

  • First, import a module from Opencv, a Python computer vision library. This module will allow us to detect the edges of an image.
  • Next, you’ll want to read in your image. To do so, you’ll use the imread() function and assign it to a variable.
  • Then, you’ll apply the canny() function to that variable, detecting the edges in your image.
  • Finally, you will use the imshow() function to display the output image with all its edges detected.

And that’s all there is to it! With just a few simple steps, you can efficiently perform edge detection using Opencv and Python.


What does OpenCV use to detect the edges of the image?

OpenCV has an in-built function, cv2.Canny(), which it uses to detect the edges of images. Edge detection generally identifies edges by detecting any discontinuities in brightness. OpenCV uses the input image as well as the aperture size in order to detect edges. Edge detection is mainly used in areas such as data extraction, image segmentation, processing, and machine vision.

What are the four steps in OpenCV for edge detection?

The four steps in Edge detection are Image smoothing, Enhancement, Detection, and Localization. Image Smoothing generally refers to filtering images to improve performance and noise reduction. Enhancement refers to increasing the quality of the digital image. At the Detection step, OpenCV detects edge points using thresholding. In the final localization stage, OpenCV precisely detects the locations of the image edges.

What is the best edge detection algorithm for OpenCV?

Canny Edge Detection in Python is generally accepted as one of the best edge detection algorithms. The algorithm is flexible and easy to use, quickly detecting image edges through its four step process. It reduces noise through image blurring in the first step itself to increase accuracy. Other options include Sobel, Roberts, Canny, and so on.

What are the different edge detectors OpenCV?

Edge Detection Operators classify under two types, Gradient-based operators and Gaussian operators. Gradient-based operators use first-order derivations to detect edges. Gusaaion operators use second-order derivatives. In OpenCV, you can use the Sobel edge detector, Canny edge detector, or Laplacian edge detector. Sobel is a gradient-based model, while Canny and Laplacian are Gaussian based.

What are the advantages of edge detection?

Edge detection in Python is highly advantageous as it helps improve processing speed. Usually, Edge detection helps significantly reduce the size of the images you process. Additionally, thin and sharp edges help increase object recognition efficiency. Edge detection allows for better observation of the features of an image. Edge detection is used for medical scans and fingerprint analysis.


Now that you know all there is to know about edge detection, it’s time to put your new skills into practice. Edge detection can be a great way to make your photos look more professional and surprisingly easy.

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