Real time frequency domain processing of medical images

The major practical problem in applying Fourier domain techniques to medical imagery has been the large number of calculations required for substantial image sizes with resultant non-real-time operation. The recent development of an imaging supercomputer with associated two-dimensional fast Fourier transform software has now made possible the calculation of (120×128)-pixel two-dimensional Fourier transforms, multiplication by an arbitrary filter function, and inverse two-dimensional Fourier transformation possible in real time. Here, plain-film projection radiographs are digitized and a variety of high-pass, low-pass and bandpass filters are applied in the transform domain. The preliminary results suggest that such real-time spatial filtering may be particularly attractive to radiologists because of the ability to see simultaneously both the unprocessed and processed radiograph and to utilize rapidly and assess a variety of available filters