Denoising With Frequency Domain

2. Denoising in spatial domain
• mean filter
• Median filter
• Max filter/Min filter
• Alpha-trimmed mean filter
• Adaptive filter
• Notch filter

3. Denoising with spatial domain
Mean filter
Median filter
https://preventionyun.tistory.com/33

4. Mean filter & Median filter

5. Denoising with Spatial domain? Frequency domain?

6. Denoising with Spatial domain? Frequency domain?
Fourier
transform
Inverse Fourier
transform

7. Base of Fourier transform
base : (1,0), (0,1) ➔ sin, cos
frequency

8. Fourier transform
Spatial domain frequency domain

9. 2D Spatial domain & frequency domain
# of Pixels (# of sampling) ➔ determine ‘highest frequency’
Window size (width) ➔ determine ‘frequency resolution’

10. Sampling and Frequency
impossible
possible
2s
→ 최대 1/2s frequency

11. Window width and freqeuncy

12. Spatial domain to Frequency domain
Low freq high freq

13. Frequency domain denoising

14. Wavelet transform
Frequency만 조절 Frequency + scale 조절

15. Wavelet transform
sacle 조절 = window width 조절
Scale 증가
Scale 증가
Scale 증가

16. Discrete Wavelet transform

17. Stationary Wavelet transform

18. CVPR Denoising Workshop

19. CVPR Denoising Workshop

20. Thank You