Unsharp masking technique using multiresolution analysis for computed radiography image enhancement.

An unsharp masking technique (USM) is one of the image processing methods used in the computed radiography (CR) system. To further promote the performance of the USM, we developed the NEW-USM processing that can control the frequency enhancement characteristics flexibly and accommodate an extensive range of diagnostic targets. The NEW-USM and USM were performed on femur images acquired by computed radiography (model FCR9000; Fuji Medical Systems USA Inc, Stamford, CT), and the resulting images were compared. In the NEW-USM image, bone structures are enhanced as sharply as in the USM image, whereas the surrounding soft tissue structures, such as muscle are enhanced more strongly than in the USM image. Furthermore, the absence of the bone structure that may suggest pathological change is more obvious in the NEW-USM image. The newly developed NEW-USM can appropriately enhance diagnostic information over the whole range of image frequencies, thereby expanding utility of the USM.