Parameters for Tikhonov Regularization

Hi all,

I am trying to use the tikhonov.m function from the regtools package written by Per Christian Hansen. I'm having some trouble with dimensions in the function and suspect that I misunderstand what the parameters are. So using the relationship Ax = b, where A is my blurring matrix, b is my original image, and x is my reconstruction, I am looking to find the correct parameters U,s,V (from SVD) and b (the original image). I take the CSVD of my blurring matrix A and stretch b out to a vector, but the dimensions simply do not work, and it must be the case that I have misunderstood how to compute these parameters. Could anyone with experience with the tikhonov.m file from regtools (or tikhonov regularization in general) explain what I am doing incorrectly/ how to compute these parameters? I would be grateful! Thanks!