Introduction to Image Processing

Work in progress. This note is still being written and incomplete.

2 min read Last updated Sun Jul 26 2026 05:09:41 GMT+0000 (Coordinated Universal Time)

This is an elective module.

Computer vision, image processing and computer graphics are 3 related domains, distinguished by their input and output.

  • Computer vision
    Input is an image, output is a description of the image.
  • Image processing
    Input is an image, output is an (enhanced) image.
  • Computer graphics
    Input is a description, output is a generated image.

Processing pipeline

An image passes through 5 stages between the real world and its final reproduction.

  • Acquire
    Convert incident light, or a non-visible source (X-ray, UV, IR, sonar, MRI, radar), into a physical or logical representation.
  • Enhance
    Correct defects introduced by the acquisition device: brightness, contrast, colour consistency, geometric distortion.
  • Store or transmit
    Encode the image for storage or transmission. Format conversion, compression, transmission errors and physical degradation (fading, scratches) can all introduce losses here.
  • Restore or recover
    Identify and remove artefacts, restore brightness and colour consistency, correct geometric distortion.
  • Reproduce
    Convert image data back into an optical image using a printer, projector or display. Output depends on the device’s ability to reproduce data as light.

Applications

  • Digital photography and videography
  • Special effect generation
  • Medical imaging
  • Security and surveillance
  • Business and government applications
  • Pre-processing for computer vision and pattern recognition
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