Pixel Detective
Zoom into images pixel by pixel, explore RGB channels, and apply real image filters — discovering exactly how computers see and understand images!
How Computers See Images
Pixels
Every image is a grid of tiny coloured squares called pixels. A 640×480 image has 307,200 pixels!
RGB Values
Each pixel has three numbers: Red (0–255), Green (0–255), Blue (0–255). These mix to make every colour.
Convolution
A small matrix (kernel) slides over the image multiplying pixel values — this creates effects like blur, sharpen, and edge detection.
CNNs Learn Filters
In deep learning, CNNs learn their own filters automatically from training data — detecting edges, textures, and shapes!
Step 1 — Explore Pixels
🔍 Pixel Inspector
Step 2 — RGB Channel Separation
Original Image
Grayscale
Step 3 — Convolution Filters
Original
Filter Result
Step 4 — Pixel Statistics & Histogram
📊 Brightness Histogram (RGB channels)
Pixel Detective Badge!
You explored pixels, separated RGB channels, and applied convolution filters!
Optional. Stays on this device only — not sent to WhizzStep.
Key Concepts Mastered
🔲 Smallest Unit
The smallest element of a digital image. Each pixel stores one colour value — in RGB, that's three numbers.
🎨 Colour Space
Red, Green, Blue — each from 0–255. Mix all three at 255 to get white. All at 0 gives black.
⚙️ Sliding Window
A kernel matrix slides over the image. At each position, it multiplies and sums values, creating a transformed output.
🔲 Finding Boundaries
Kernels that highlight rapid colour changes. The basis of how CNNs detect object outlines and shapes.
📊 Pixel Distribution
Shows the frequency of each brightness level. Used for image analysis, normalisation, and contrast adjustment.
🧠 Learned Filters
Convolutional Neural Networks learn their own filters from data — detecting edges, textures, and complex patterns automatically.
About this lab
Learning objective: Explore how an image is represented as pixels and numbers, and how a simple model uses that representation to classify it.
What this simplifies: A small set of low-resolution images is used; real computer-vision systems process far higher-resolution data.
Privacy: No learner input leaves the device.
Teacher prompt: Ask the class why this simulation might mislead someone who takes it too literally.
Reflect: What is one thing this activity showed you that you did not expect?
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