Digital image processing to remove blur from linear tomography of the lung

We have studied digital image processing methods to reduce blur in linear tomography of the lung performed with the Fuji computed radiography (FCR) system. One-dimensional unsharp (blur) mask filtering in the direction of tomographic movement was found to be effective in reducing blur. The appearance of the processed tomograms varied depending largely on the properties of the unsharp mask filters applied. With regard to the spatial frequency response of the filter, a high mid-frequency response and a low low-frequency response of the tomographic image data was most effective in obtaining high image quality tomograms. When the standard 2-dimensional unsharp mask technique of the FCR system was additionally applied to the one-dimensional unsharp mask processed tomogram, the clarity of the tomogram was further enhanced. These observations may also be helpful when considering image processing to obtain diagnostically informative digital radiography. (orig.)