Object Extraction

Process: Segment: Object Extractor...

• Used to pull out specific features
• Isolate range of data to extract
• Whups the pants off "Image Extractor"
• Steps:
  1. Thresholds
  2. Erodes
  3. Dialates
  4. Connects / Fills

Notes

The Object Extractor, found under the "Process:Segment:Object Extractor" menu, does a wonderful job of pulling objects out of the data. The data be aligned to use this, because it sure helps reduce weird errors.

Pick a seed point in an interior slice. Expand the threshold region until the region you are interested in is outlined in red. Click on extract and go out for some coffee. Your object will be extracted.

What is going on here? The software is constantly thresholding the data, eroding away portions that are potentially useless, dialating the dataset which restores connections that might have been mis-eroded, and filling in the holes. It does this repeatedly until no further changes are made.

For Demo

• Select the mri3Dhead dataset
• Process: Segment: Object Extractor...
• View: Size. Chose Triple and resize window
• Generate: Define Region... (first PowerBar button)
• Chose slice 120 and select Define Region
• Click on "Limit" and circumscribe the brain inside the skull
• Click on "Auto Trace" and select a point in the brain.
• Adjust the sliders to 50 and 150
• Click on "Extract Object"
• Click on "Fill Holes: On" then "OK".
• Move processing windows into projection screen.
• Move resulting window to the top.

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