🎥 Cameras, Sensors & Pixels

Understanding how cameras capture light and convert it into digital data is crucial for Computer Vision. This page breaks down the camera’s components, sensor operation, pixels, and image resolution.

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1. What is a Camera in Computer Vision?

In Computer Vision, a camera is a device that converts light from the real world into a digital image. Think of it like a translator:

🌍 Light from the real world → 🎥 Camera → 🏛 Digital data (pixels)

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2. What’s Inside a Camera?

a. 🎯 Lens

• Focuses incoming light rays onto the sensor.
• Adjusting the lens changes focus and field of view.

b. 🔍 Aperture

• Controls how much light enters.
• A small aperture = less light (sharper depth of field), large aperture = more light (brighter image).

c. ⏱ Shutter

• Controls how long the sensor is exposed to light.
• Fast shutter = crisp motion; slow shutter = motion blur.

d. 📦 Image Sensor (the core)

• The sensor is made up of tiny light-sensitive cells called pixels.
• Common sensor types:
  • CCD (Charge-Coupled Device)
  • CMOS (Complementary Metal Oxide Semiconductor)

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3. How Sensors Work

Each pixel on the sensor measures the intensity of light hitting it:

• More light = higher value (brighter)
• Less light = lower value (darker)

This yields a grid of numbers—a matrix that becomes your digital image!

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4. Pixels: The Smallest Unit

• A pixel is the smallest measurable unit in an image.
• Each pixel holds one or more values depending on image type:
  • Grayscale = 1 value (0–255)
  • RGB = 3 values (R, G, B channels)

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5. Resolution and Size

• Resolution = number of pixels in width × height (e.g., 1920 × 1080)
• More pixels → more detail → larger file size

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🔄 Summary Table

Component	Function
Lens	Focuses incoming light
Aperture	Controls light amount
Shutter	Controls exposure time
Sensor	Captures light at pixel level
Pixel	Stores light intensity / colour info