Interactive high-quality maximum intensity projection

Maximum Intensity Projection (MIP) is a volume rendering technique which is used to visualize high-intensity structures within volumetric data. At eac h pixel the highest data value, which is encountered along a corresponding viewing ray is depicted. MIP is, for example, commonly used to extract vasc ular structures from medical data sets (angiography). Due to lack of depth information in MIP images, animation or interactive variation of viewing pa rameters is frequently used for investigation. Up to now no MIP algorithms exist which are of both interactive speed and high quality. In this paper w e present a high-quality MIP algorithm (trilinear interpolation within cell s), which is up to 50 times faster than brute-force MIP and at least 20 tim es faster than comparable optimized techniques. This speed-up is accomplish ed by using an alternative storage scheme for volume cells (sorted by value ) and by removing cells which do not contribute to any MIP projection (rega rdless of the viewing direction) in a preprocessing step. Also, a fast maxi mum estimation within cells is used to further speed up the algorithm.