OpenCV Workshop

A hands-on introduction to computer vision for first-year engineering students. No prior experience needed. You'll go from reading a single image to projecting a spinning 3D cube, one concept at a time.

What is OpenCV?

OpenCV (Open Source Computer Vision Library) is the go-to tool for anything vision-related in Python. Think of it as numpy, but for images and cameras. It's used everywhere: from detecting faces on your phone to self-driving cars figuring out where the road is.

This workshop covers the foundations: how to read, manipulate, filter, and draw on images, and then applies that math to make things move.

Folder Structure

opencv-workshop/
├── assets/                        # Input images used by the scripts
├── basics/                        # Core concepts, run in order (1 to 9)
│   ├── constants.py               # Shared file paths (just import, don't edit)
│   ├── 1io.py                     # Reading/writing images and webcam capture
│   ├── 2shape_colours.py          # Image dimensions and color spaces
│   ├── 3bitwise_threshhold.py     # Bitwise ops, masking, thresholding
│   ├── 4drawing_shapes.py         # Drawing shapes and text on images
│   ├── 5convulation_kernel.py     # Kernels, filters, and padding
│   ├── 6contours.py               # Edge detection and contour analysis
│   ├── 7morphology.py             # Erosion, dilation, and morphological ops
│   ├── 8rotating_hexagon_maths.py # Animated hexagon using trigonometry
│   └── 9rotating_cube_maths.py   # 3D cube with rotation matrices
├── projects/                      # Mini-projects built on the basics
│   ├── fruit_ninja.py
│   ├── invisible_cloak.py
│   └── shield.py
├── requirements.txt               # All Python dependencies
└── README.md

Basics: What Each File Covers

File	Concept	Description
1io.py	Image and Video I/O	Load an image, show it, save it, capture from webcam
2shape_colours.py	Shapes and Color Spaces	Images are just arrays; colors depend on the space you use
3bitwise_threshhold.py	Bitwise Ops and Thresholding	Combine or isolate parts of an image using logic operations
4drawing_shapes.py	Drawing	Paint rectangles, circles, text, and polygons on any image
5convulation_kernel.py	Convolution Kernels	Slide a small matrix over the image to sharpen, blur, or emboss it
6contours.py	Contours and Edges	Find object outlines and describe their shape
7morphology.py	Morphological Ops	Shrink or grow white regions to clean up binary images
8rotating_hexagon_maths.py	Trig Animation	Use sin and cos to spin a hexagon on the webcam feed
9rotating_cube_maths.py	3D Projection	Rotate a 3D cube and project it flat onto your screen

Setup

1. Make sure you have Python 3.12

python --version

Don't have it? Download from python.org.

2. Create a virtual environment (recommended)

python -m venv venv
source venv/bin/activate        # Mac/Linux
venv\Scripts\activate           # Windows

3. Install dependencies

pip install -r requirements.txt

This installs OpenCV, NumPy, MediaPipe, and everything else the projects need.

How to Run

All scripts in basics/ import from constants.py, so run them from inside the basics/ folder:

cd basics
python 1io.py

Quick Reference

Script	Command	Notes
1io.py	python 1io.py	Opens webcam, press Q to stop
2shape_colours.py	python 2shape_colours.py	Press any key to close windows
3bitwise_threshhold.py	python 3bitwise_threshhold.py	Multiple windows open in sequence
4drawing_shapes.py	python 4drawing_shapes.py	Press any key to close
5convulation_kernel.py	python 5convulation_kernel.py	Press any key to close
6contours.py	python 6contours.py	Press any key to close
7morphology.py	python 7morphology.py	Multiple windows, press any key each time
8rotating_hexagon_maths.py	python 8rotating_hexagon_maths.py	Live webcam, press ESC to exit
9rotating_cube_maths.py	python 9rotating_cube_maths.py	Live webcam, press ESC to exit

If a window seems frozen, click on it and press any key. OpenCV needs focus to register keypresses.

Webcam Note

Files 1io.py, 8rotating_hexagon_maths.py, and 9rotating_cube_maths.py open your webcam. Make sure it's connected and not in use by another app.

Prerequisites

You don't need to know computer vision. You do need to be comfortable with:

• Basic Python (variables, loops, functions)
• A little numpy wouldn't hurt, but it's not required

What's Next?

Once you're through the basics, check out the projects/ folder:

• Invisible Cloak: Harry Potter vibes, achieved with color masking
• Fruit Ninja: Slash moving objects detected by the camera
• Shield: A reactive visual overlay on your hand

These all build directly on the concepts from basics/. Good luck, and yes, the rotating cube is as cool as it sounds.