Extract and expand a specific range of attenuation values with renormalization to perceive greater detail in multi-material scans.
Volumetric data is stored as a cube of voxels that each have an attenuation value. The extremely high resolution source volume contains both more voxels than we can display within Voyager, but also much more color depth than we can support.
The ROI tool allows you to choose a spatial region of interest of your part that you wish to see in high resolution. In a similar way, the rangemapper along with the renormalization tool allows you to choose a region of attenuation that is most interesting to you.
Tip: The renormalization tool is accessible within the ROI tool.
How to use Renormalization
Renormalization is one of the controls that the ROI workflow affords in Voyager.
- Select the volume that you wish to renormalize in the data panel on the left.
- Click the ROI button in the toolbar to launch the ROI workflow.
- Use the rangemapper within the ROI tool to isolate the material that you wish to renormalize the resulting volume to.
- The left side of the data in the rangemapper histogram is the less attenuating material (less dense). If you wish to separate the plastic from the metal in a multi-material part, use the rangemapper to select a portion of the left side of the data.
- The right side of the data in the rangemapper histogram is the more attenuating material (more dense). If you wish to separate the metal from the plastic in a multi-material part, use the rangemapper to select a portion of the right side of the data.
- Once the visualization and the ROI represent the section of the scan that you care about and the material portion of the scan that is important to you, scroll to the bottom of the ROI tool and select "Selected Range".
- Press Generate ROI to request the specified ROI.
Renormalization Options
There are three options in the Renormalize section of the ROI tool. Default Range, Selected Range and Full Range.
- Default Range: Refers to the default normalization that Voyager applies to volumes after they have been created. Use this option to "reset" the volume to what Voyager typically displays.
- Selected Range: Refers to the user specified values that the rangemapper and visualization show. Us this to choose a specific range of your data to renormalize to.
- Full Range: Refers to the raw, unclipped data. Use this if you believe the default range has clipped important data from your scan. This is possible with extremely high variation multi-material datasets where your application requires resolution of extremely different materials in one scan.
Renormalization Results
Renormalization is a useful tool to improve your data quality and expand the range of the material that you care most about. The below scan shows a standard low attenuation / high attenuation split. Renormalization allows you to isolate less dense and more dense material into their own individual volumes.
