Reduction of boundary artifacts in image restoration

TitleReduction of boundary artifacts in image restoration
Publication TypeJournal Article
Year of Publication1996
AuthorsAGHDASI, F., and R. K. Ward
JournalImage Processing, IEEE Transactions on
Pagination611 -618
Date Publishedapr.
Keywordsabrupt boundary truncation, boundary artifacts reduction, circular convolution, computational complexity, computational effort, convolution, deconvolution, discrete Fourier transform, discrete Fourier transforms, image distortion, image padding, image restoration, linear deconvolution method, periodic convolution, restoration filter, smoothing, smoothing methods

The abrupt boundary truncation of an image introduces artifacts in the restored image. The traditional solution is to smooth the image data using special window functions such as Hamming or trapezoidal windows. This is followed by zero-padding and linear convolution with the restoration filter. This method improves the results but still distorts the image, especially at the margins. Instead of the above method, we propose a different procedure. This procedure is simple and exploits the natural property of ldquo;circular rdquo; or periodic convolution of the discrete Fourier transform (DFT). Instead of padding the image by zeros, it is padded by a reflected version of it. This is followed by ldquo;circular rdquo; convolution with the restoration filter. This procedure is shown to lead to better restoration results than the windowing and linear convolution techniques. The computational effort is also improved since our method requires half the number of computations required by the conventional linear deconvolution method


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