CHS

The segmentation and classification, i.e. reconstruction, of the Visible Human data set is the portion of the project currently in progress. This involves the tedious task of distinguishing structures, slice by slice. The next step requires the use of one of three computers to take this information and compile it into individual three dimensional structures. The systems used for this process include the Cray Y-MP8 at the National Center for Atmospheric Research, in Boulder, the SGI Onyx at NCAR's Visualization Lab, or a Hewlett-Packard J200 9000 located within CHS.

Segmentation and classification of the Visible Human Male began in December 1995 , and is expected to be completed within a year.

The following illustrations are meant to provide you with an idea of the magnitude of this project.

This is an image of the raw data used for the seg.&class. The images are cropped to include the target structures. The targeted structures in this slice are the kidneys.

After the entire volume of slices containing the kidneys is cropped, those slices are run through various computer programs that define all of the edges within the slice. The computer recognizes edges as areas of contrast.

When the computer finishes trying to distinguish the edges, each slice is scrutinized by assistants within the lab. They must inspect each slice individually to correct any mistakes made by the computer. Sometimes the contrasts between structures is negligible, so we must manually draw these lines of distinction.

Once the structures are completely outlined from the surrounding tissue, the separated area is filled with a specific color, similar to the 'fill' function of most paint programs. This is done for each slice, keeping the 'fill' color identical for the same structure, throughout the volume. This information is then passed on to one of the computers mentioned earlier for compiling.

The completed product looks something like this. This animation actually shows the muscles and skeletal system of the lower back, in addition to the kidneys with their associated vascular tissue. Colors and texture mapping are derived directly from the raw data. Upon completion, every structure in the Visible Human Male will be rendered in three dimensions, just like this. (This animation is available in MPEG format, 1.2MB, or as a higher resolution Quicktime Movie format, 5.9 MB.)