How does radius of point spread function affect reconstruction errors?

Click For Summary
SUMMARY

The discussion focuses on the impact of the radius of the Gaussian point spread function (PSF) on reconstruction errors in image processing. The user applies Gaussian blur and Gaussian white noise to an image, then attempts to reconstruct the original image using a naive solution involving the blurred image and the PSF. It is concluded that increasing the radius of the Gaussian blur results in higher noise levels in the reconstructed image due to decreased signal-to-noise ratio (SNR) per pixel, as the PSF spreads over more pixels while the percentage of added noise remains constant.

PREREQUISITES
  • Understanding of Gaussian blur and its effects on images
  • Familiarity with point spread functions (PSF) in image processing
  • Knowledge of eigenvalues and their computation using fast Fourier transforms (FFT)
  • Basic principles of signal-to-noise ratio (SNR) in imaging
NEXT STEPS
  • Research Gaussian blur parameters and their influence on image quality
  • Learn about the mathematical foundations of point spread functions (PSF)
  • Explore fast Fourier transforms (FFT) and their applications in image reconstruction
  • Investigate methods to improve signal-to-noise ratio (SNR) in image processing
USEFUL FOR

Image processing professionals, astrophotographers, and anyone interested in understanding the effects of Gaussian blur and noise on image reconstruction accuracy.

cp05
Messages
11
Reaction score
0
Hi guys,
I've been struggling with this concept for a few days now.
I have this *good* image that I am blurring (using a gaussian blur), then adding some small percentage of gaussian white noise to it. Then from that image, I want to compute the naive solution (just assuming B=AX and solving for X...where B is the blurred image I created and X is the *good* image, with A being the matrix that takes into account this gaussian point spread function).

I have a handy dandy textbook that says that if I use periodic boundary conditions (which I am), then I can just use the point spread function and don't ever have to construct A (yay!). I do this by computing the eigenvalues of A using fast Fourier transforms (not sure how those work either...but I guess that's a different question for a different time), then using the inverse fast Fourier transform to solve for X using the blurred matrix and those eigenvalues of A.

All great!

By playing around with the radius of my gaussian blur...I notice that at larger gaussian blur radii (ad same % of white noise), my resulting naive X solution has a lot more noise! So I was wondering if anyone can help me figure out why this happens. Why am I getting more noise in my solution with larger radii of blur...because I am not changing the % of white noise at all!

If someone could help, or point me in the right direction, I would be ever grateful.
Thanks!
 
Physics news on Phys.org
Random guess, but wouldn't the larger blur mean less SNR per pixel and more total noise that is added to each calculation since you have the PSF spread over more pixels?
(I hope that makes sense. My only knowledge of this subject comes from my astrophotography)
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 9 ·
Replies
9
Views
2K
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 6 ·
Replies
6
Views
3K
Replies
42
Views
9K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 0 ·
Replies
0
Views
1K