Digital signal and image processing
Tier list
Ranking image enhancement methods for exams
I ranked image enhancement methods by exam value. Number one surprises people.
Quick check · tap an answer to continue
Lesson notes
Key points
- Image negative: It is simply s equals L minus one minus r, easy marks but rarely the main question.
- Log transform: Useful for compressing huge dynamic range, like Fourier spectra, but usually a short question.
- Gamma correction: Power-law curves show up in display and contrast questions, often with a quick calculation.
- Histogram equalisation: It spreads grey levels using the cumulative distribution, and examiners love asking you to compute it by table.
Takeaway: Practise histogram equalisation by hand; it's the exam favourite.
Quick check: Histogram equalisation maps grey levels using what function?
- The cumulative distribution
- The image negative
- A log curve
Equalisation uses the CDF of grey levels to spread them across the range.
Lessons like this, for your syllabus.
Short narrated study videos written for your course, level and exam. Free to start.
Get lessons for your own syllabus