What This Document Is
This document introduces rank order filtering, a technique used in computer graphics for image processing. It builds upon the concept of median filtering and expands it to include minimum and maximum order filters. The document provides practical examples using MATLAB code, specifically the `ordfilt2` function, to demonstrate how these filters can be applied to images. It also touches upon normal distribution filtering and its implementation using the `fspecial` function.
Why This Document Matters
This material is valuable for students and professionals in computer graphics, image processing, and computer vision. Understanding rank order filtering is crucial for tasks like noise reduction and image enhancement. It’s typically used in courses covering digital image processing techniques and serves as a foundation for more advanced filtering methods. The practical MATLAB examples make it useful for implementing these techniques in real-world applications.
Common Limitations or Challenges
This document focuses on the *application* of rank order filtering, not the underlying mathematical theory. It assumes a basic understanding of image processing concepts and MATLAB programming. It doesn’t delve into the complexities of choosing optimal filter sizes or handling different types of noise beyond salt & pepper and local variance. It also doesn’t cover advanced topics like adaptive filtering or multi-dimensional rank order filtering.
What This Document Provides
The full document includes:
* Explanations of minimum, maximum, and median order filtering.
* MATLAB code examples demonstrating the use of `ordfilt2` for various filtering tasks.
* Illustrative figures showing the effects of different filters on sample images (forest.tif).
* Problem sets designed to reinforce understanding and practical application of the concepts. These problems involve applying filters to images, analyzing results, and experimenting with different parameters.
* An introduction to normal distribution filtering and its implementation with `fspecial`.
* Exercises involving region-of-interest (ROI) filtering using `roipoly`.
This preview does *not* include solutions to the problem sets, the full MATLAB code listings, or a detailed mathematical derivation of the filtering algorithms. It provides a high-level overview of the topics covered.
