Canny Edge Detection OpenCV Python With Source Code

Canny Edge Detection OpenCV Python With Source Code

The Canny Edge Detection OpenCV Python Code was developed using Python OpenCV, This Canny Edge Detector is a multi-step algorithm used to detect a wide range of edges in images.

The Canny edge detector is arguably the most well known and the most used edge detector in all of computer vision and image processing.

A Canny Edge Detection uses a filter based on the derivative of a Gaussian in order to compute the intensity of the gradients. The Gaussian reduces the effect of noise present in the image.

In this Python OpenCV Project also includes a downloadable Python Project With Source Code for free, just find the downloadable source code below and click to start downloading.

What is OpenCV?

OpenCV (Open Source Computer Vision Library) is an open-source computer vision and machine learning software library.

OpenCV was built to provide a common infrastructure for computer vision applications and to accelerate the use of machine perception in commercial products.

By the way if you are new to python programming and you don’t know what would be the the Python IDE to use, I have here a list of Best Python IDE for Windows, Linux, Mac OS that will suit for you. I also have here How to Download and Install Latest Version of Python on Windows.

To start executing Canny Edge Detection OpenCV Python With Source Code, make sure that you have installed Python 3.9 and PyCharm in your computer.

Canny Edge Detection OpenCV Python With Source Code : Steps on how to run the project

Time needed: 5 minutes

These are the steps on how to run Canny Edge Detection OpenCV Python With Source Code

  • Step 1: Download the given source code below.

    First, download the given source code below and unzip the source code.Canny Edge Detection OpenCV download source code

  • Step 2: Import the project to your PyCharm IDE.

    Next, import the source code you’ve download to your PyCharm IDE.
    Canny Edge Detection OpenCV open project

  • Step 3: Run the project.

    last, run the project with the command “py main.py”
    Canny Edge Detection OpenCV run project

Installed Libraries

import cv2 as cv
import numpy as np
from matplotlib import pyplot as plt

Complete Source Code

import cv2 as cv
import numpy as np
from matplotlib import pyplot as plt


def canny():
    '''
    The Canny edge detection algorithm is composed
                      of 5 steps:

    1. Noise Reduction
    2. Gradient Calculation
    3. Non-maximum Suppressions
    4. Double threshold
    5. Edge Tracking by Hysteresis
    '''
    img = cv.imread("./img/sunflower.jpg", 0)
    canny = cv.Canny(img, 150, 200)

    title = ["Original Image", "Canny"]
    images = [img, canny]

    for i in range(len(images)):
        plt.subplot(2, 2, i+1), plt.imshow(images[i], 'gray')
        plt.title(title[i])
        plt.xticks([]), plt.yticks([])

    plt.show()


if __name__ == '__main__':
    canny()

Output

Canny Edge Detection OpenCV Python Output
Canny Edge Detection OpenCV Python Output

Download Source Code below

Anyway, if you want to level up your programming knowledge, especially Python OpenCV, try this new article I’ve made for you Best OpenCV Projects With Source Code For Beginners 2021.

Summary

In this Python OpenCV Project With Source Code, we learned how to use image gradients, one of the most fundamental building blocks of computer vision and image processing, to create an edge detector.

Specifically, we focused on the Canny edge detector, the most well known and most used edge detector in the computer vision community.

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Inquiries

If you have any questions or suggestions about Canny Edge Detection OpenCV Python With Source Code, please feel free to leave a comment below.

Technology stack and requirements

To run this Python project on your development machine, you need:

  • Python 3.10 or higher. Download from python.org or install via Anaconda if you prefer bundled packages.
  • pip package manager. Comes with Python. Used to install project dependencies from requirements.txt.
  • Virtual environment. Use venv or conda to isolate project dependencies from your global Python install.
  • VS Code or PyCharm. Free code editors with Python syntax highlighting, IntelliSense, and debugging.
  • Git. For version control and cloning source code repositories.

Installing the source code

  1. Download or clone the repository. Get the ZIP archive from the download link on this page and extract it.
  2. Create a virtual environment. Open a terminal in the project folder and run: python -m venv venv, then activate it (venv\Scripts\activate on Windows or source venv/bin/activate on Mac/Linux).
  3. Install dependencies. Run pip install -r requirements.txt to install all libraries the project needs.
  4. Configure environment variables. If the project uses API keys (OpenAI, Anthropic, database), create a .env file and set the required keys.
  5. Run the project. Follow the run command in the README (usually python main.py or streamlit run app.py).

Using this project for your BSIT capstone

  • Chapter 1 (Introduction). Discuss the real-world problem this system solves. Cite Philippine or international use cases where the manual process could be automated.
  • Chapter 2 (RRL). Compare your project against 5-10 similar published works. Cite ACM, IEEE, or arXiv papers for academic-standard sources.
  • Chapter 3 (Methodology). Document the model architecture, training data, hyperparameters, and evaluation metrics used.
  • Chapter 4 (Results). Report accuracy, precision, recall, F1-score, and confusion matrix. Screenshot the running app on real inputs.
  • Chapter 5 (Conclusion). Identify features for Version 2: better model, larger dataset, mobile deployment, or REST API.

Modules typical of Canny Edge Detection OpenCV Python

  • Image dataset preparation. Train/val/test split, augmentation (rotation, flip, brightness).
  • Model architecture. Pre-trained CNN (ResNet, EfficientNet) fine-tuned on your dataset.
  • Training loop. PyTorch or TensorFlow/Keras training with early stopping and checkpoints.
  • Evaluation. Confusion matrix, precision, recall, and per-class F1 scores.
  • Inference API. FastAPI endpoint accepting image uploads and returning predictions.
  • Web or mobile demo. Streamlit or React front-end for user interaction.

Common enhancements for capstone review

  • Grad-CAM visualization. Show which pixels the model focused on when making a prediction.
  • Data augmentation. Increase training data variety with imgaug or Albumentations library.
  • Transfer learning benchmark. Compare training-from-scratch vs fine-tuning pre-trained models.
  • Model quantization. Convert to TensorFlow Lite for mobile deployment.

Frequently Asked Questions

How does Canny edge detection work?

Five steps internally: noise reduction (Gaussian blur), gradient calculation (Sobel), non-maximum suppression (thin edges), double thresholding (keep strong edges, conditionally keep weak), edge tracking by hysteresis. In OpenCV: cv2.Canny(img, lower, upper). Lower threshold around 50, upper around 150 work for most images, tune with a trackbar for your scene.

What OpenCV version do I need to run this project?

Use OpenCV 4.5 or newer. Install with pip install opencv-python (the standard build for desktop projects). Some projects also need opencv-contrib-python which adds extra modules (SIFT, SURF, advanced trackers). The pip install command auto-downloads pre-built wheels so no compilation is needed on Windows, Mac, or Linux.

How do I install OpenCV and the dependencies for this project?

Open a terminal, then: pip install opencv-python numpy. Most projects also need one of these: mediapipe (for face / hand / pose detection), pyzbar (for barcode and QR), pytesseract (for OCR), Pillow (for image manipulation), pyautogui (for screen capture). Pin Python version to 3.10, 3.11, or 3.12 for maximum library compatibility.

Can I use this OpenCV project for a BSIT or CSE capstone?

Yes, but extend it. A single OpenCV demo (face detection alone, lane detection alone) is too narrow for full capstone scope. Combine it with a real domain (attendance system using face recognition, traffic monitoring system using lane detection, fitness coach app using pose detection), add a database to log results, build a simple Tkinter or Streamlit UI, and document the whole pipeline in Chapter 3.

Why am I getting AttributeError or ImportError when running this code?

Three most common causes: (1) You installed opencv-python but the code needs opencv-contrib-python (extra modules like xfeatures2d). Reinstall with pip install opencv-contrib-python. (2) You are on Python 3.13 but some wheels (mediapipe) lag behind, downgrade to Python 3.11 or 3.12. (3) NumPy version mismatch, pin numpy to a version your other libraries support.

Where do I find more OpenCV and Machine Learning project ideas?

Browse our Machine Learning Projects hub for 23+ OpenCV demos with source code. For capstone-scale AI ideas (RAG, NLP, recommendation systems), see 100+ AI Capstone Project Ideas. For broader Python project ideas, our Python Projects library has 250+ working capstones.

Angel Jude Suarez


Full-Stack Developer at PIES IT Solution

Focuses on Python development, machine learning, and AI integration. Has built production AI systems including OpenAI Whisper integration for medical transcription and GPT-4o-powered diagnosis assistance. Strong background in pandas, scikit-learn, and TensorFlow.

Expertise: Python · PHP · Java · VB.NET · ASP.NET · Machine Learning · AI Integration · OpenCV · Django · CodeIgniter
 · View all posts by Angel Jude Suarez →

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