1 May 1992 Automatic removal of unexposed background in digital radiographs
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In digital radiographs with significant collimation, there is a noticeable amount of unexposed background remaining in the image. This unexposed portion appears as bright white on the video display. We have developed a method that automatically removes this unexposed background and converts it to black background. This is less distracting to the viewer when the image is displayed on a video monitor. The algorithm first searches for the raw edges of an image. The next stage is to reconcile these edges to find the corner points. From these corner points, we interpolate to obtain straight line boundaries. The estimated boundaries are then checked with an error-correction procedure to verify that these points are outside the image. The error-corrected contour is then drawn using smooth line techniques and setting points outside the contour to black. This method has been implemented in a PACS environment and works well for images with significant collimation (i.e., pediatric cases and hand images). The amount of distracting unexposed background has been noticeably reduced. In a survey of CR images needing background removal, 89.5% of all images had all or part of the background removed and 10.5% had no background removed.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael F. McNitt-Gray, Michael F. McNitt-Gray, Sandra Lee Eldredge, Sandra Lee Eldredge, James Tagawa, James Tagawa, H. K. Huang, H. K. Huang, } "Automatic removal of unexposed background in digital radiographs", Proc. SPIE 1653, Medical Imaging VI: Image Capture, Formatting, and Display, (1 May 1992); doi: 10.1117/12.59523; https://doi.org/10.1117/12.59523

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