Problem 930. 1D DCT-II transform.
Implement a function that calculates 1D Discrete Cosine Transform (DCT-II) for each row of a given input matrix so that the outputs are in columns.
For example:
Input:
[1 0 0 0]
Gives:
mydct([1 0 0 0]) ans = 0.5 0.65328 0.5 0.2706
Solution Stats
Problem Comments
-
1 Comment
A fair warning to the challenger: the requested DCT-II is the orthogonal version, which means it needs to be multiplied by sqrt(2/N) where N is the size of the row, and the first element of the DCT x0 needs to be multiplied by 1/sqrt(2). It took me a while to understand. Wikipedia's formula is almost right, but it is missing those terms, which are mentioned only further below. Look at MATLAB's documentation (DCT-2), https://www.mathworks.com/help/signal/ref/dct.html, to find the proper formula.
Solution Comments
Show commentsProblem Recent Solvers19
Suggested Problems
-
Sort a list of complex numbers based on far they are from the origin.
5545 Solvers
-
2192 Solvers
-
Remove the small words from a list of words.
1436 Solvers
-
112 Solvers
-
Project Euler: Problem 6, Natural numbers, squares and sums.
2048 Solvers
More from this Author4
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!