/DCT-2D-filter

Sliding 2D-DCT matrix (image) filter (TUT course project)

Primary LanguageCMIT LicenseMIT

DCT-2D-filter

License: MIT

Overlapping 2D Discrete Cosine Transform matrix (image) filter based on non-linear thresholding, written in C. The original reference of 2D-DCT transform functions (dct.c/h) unknown (from SGN-3057 course, TUT).



sigma PSNR +- std (noisy) [dB] PSNR +- std (denoised) [dB] optimal threshold
5 34.15 +- 0.01 38.15 +- 0.29 12.1
10 28.14 +- 0.02 33.34 +- 0.88 36.2
15 24.61 +- 0.01 32.75 +- 0.48 39.3
20 22.14 +- 0.01 31.29 +- 0.63 57.4
25 20.25 +- 0.01 30.55 +- 0.27 68.5
30 18.73 +- 0.01 29.44 +- 0.30 78.5
35 17.45 +- 0.01 28.72 +- 0.36 100.7
40 16.38 +- 0.01 27.67 +- 0.42 105.7
45 15.45 +- 0.01 26.88 +- 0.43 126.8
50 14.65 +- 0.01 26.12 +- 0.53 145.0


Compile filter

Tested with g++ 9.3

g++ -O3 dctfilter.c dct.c -o dctfilter

Run filter

Input and output type is a 64-bit floating point single channel matrix

./dctfilter [-i inputfile] [-o outputfile] [-m nrows] [-n ncols] [-s step] [-t threshold] [-q quiet]

Run full simulations

Gaussian simulations with varying noise levels

conda create -y --name dctfilter python==3.9.0
conda activate dctfilter
pip install -r requirements.txt

python simulate.py

Mikael Mieskolainen, {2011, 2021}