An algorithm is quickly scans a digital image volume to detect density
nodules. A first stage is based on a transform to quickly highlight
regions requiring further processing. The first stage operates with
somewhat lower sensitivity than is possible with more detailed analyses,
but operates to highlight regions for further analysis and processing.
The transform dynamically adapts to various nodule sizes through the use
of radial zones. A second stage uses a detailed gradient distribution
analysis that only operates on voxels that pass a threshold of the first
stage.