Inverse Problem: examples
Denoising
- $A=\mathrm{Id}_N$
$$ y = x + n $$
Deconvolution
- $A$ is a Toeplitz matrix, or convolution matrix ($M\leq N$)
$$ y = Ax + n = h*x + n $$ $$ \hat y = \hat h \hat x + \hat n $$
Inpainting
- $A$ is a binary matrix ($a_{ij} = 1$ if the pixel is measured, $a_{ij} = 0$ if the pixel is not measured)
Compressive sensing
- $A$ is a random matrix (with $M<N$)