Recognition of Images Degraded by Gaussian Blur

We introduce a new theory of invariants to Gaussian blur. The invariants are defined in Fourier spectral domain by means of projection operators and, equivalently, in the image domain by means of image moments. The application of these invariants is in blur-invariant image comparison and recognition. The behavior of the invariants is studied and compared with other methods in experiments on both artificial and real blurred and noisy images.