How to cartoon-ify an image programmatically?

by

Here’s some algorithms to play with:

  • Median or repeated box blur filter to obtain cartoonish color palette
    • Edit: Bilateral filtering should suit your needs even better
  • Min filter (zeroth percentile) to enhance some types of edges
  • Color image segmentation using either small subcube or sphere in the RGB color cube
  • Generic edge enhancement on segmented image using edge detection such as Sobel kernels or 8-way edge tracing
  • Composit blurred/median-filtered image with enhanced edges

These are fairly basic and all very easy to implement. Keep in mind that median and box blur filters can be implemented with linear time complexity w.r.t. the kernel radius.

More edits:

Once you get the idea of Huang’s algorithm, implementing a box blur filter is a delicious piece of cake.

Reading material:

  • Fast Median and Bilateral Filtering (get the PDF)
  • Median Filtering Constant time (get the PDF) Note: I have an implementation of this in C# using Mono/SIMD to accelerate histogram coalescence, however it only seems better than the O(r) algorithm when the diameter exceeds ~60 pixels due to the comparable number of add/sub instructions (the break-even point), a C++ implementation is probably much better suited to harness SIMD.

Other reading materials include Gonzalez & Woods’ Digital Image Processing (seems to be an older edition) for segmentation and edge tracing. 8-way edge tracing can be really hard to bend your head around (choosing between on-pixel or between-pixel edges and how to latch onto edges). I’d be happy to share some code, but the hundred-liners don’t exactly fit smoothly in here.

More Related Contents:

  1. complexity in terms of big O
  2. Find a pair of elements from an array whose sum equals a given number
  3. Find all paths between two graph nodes
  4. Why is the constant always dropped from big O analysis?
  5. find the only unpaired element in the array
  6. Sort points in clockwise order?
  7. How do you calculate the average of a set of circular data? [closed]
  8. Algorithm to check similarity of colors
  9. Why do we use Base64?
  10. Heap vs Binary Search Tree (BST)
  11. Finding maximum for every window of size k in an array
  12. Generate all unique substrings for given string
  13. How to Compute OBB of Multiple Curves?
  14. Counting the adjacent swaps required to convert one permutation into another
  15. Calculating new longitude, latitude from old + n meters
  16. Largest circle inside a non-convex polygon
  17. How to check if line segment intersects a rectangle?
  18. How to compare two shapes?
  19. Generate a list of primes up to a certain number
  20. Best Fit Scheduling Algorithm
  21. Algorithm to find multiple string matches
  22. help in the Donalds B. Johnson’s algorithm, i cannot understand the pseudo code (PART II)
  23. Finding how similar two strings are
  24. An inverse Fibonacci algorithm?
  25. Design an efficient algorithm to sort 5 distinct keys in fewer than 8 comparisons
  26. Unbiased random number generator using a biased one
  27. Why is vector array doubled?
  28. maximum subarray of an array with integers [duplicate]
  29. CUDA stream compaction algorithm
  30. Can brute force algorithms scale?

Leave a Comment