Caret7:Design/Thresholding

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Thresholding

Thresholding is used to inhibit the display of data that does not meet a numerical constraint such as a statistical significance.

Types

Caret5 and Caret6 both have three types of thresholding that emerged as a result of multi-fiducial mapping.

  • Column - These values are stored in the metric file for each column and are the values entered when mapping a volume using the Attributes->Map Volume(s) to Surface(s) Dialog.
  • Avg Area - These values are stored in the metric file for each column and are a result of the values entered when mapping a volume using the Attributes->Map Volume(s) to Surface(s) Dialog and using Multi-Fiducial Mapping (MFM). When mapping using MFM, the volume is mapped onto each of the twelve surfaces and then the average of these twelve mappings is computed and stored in a metric column. For each of the twelve surfaces, a count of the number of nodes exceeding each of the positive and negative thresholds is found and then an average of these counts is deteremined. The MFM metric column is sorted and the Avg Area threshold is set to the value of the node at the "average count" index from the maximum and minimum values.
  • User - These values may be entered by the user and are neither stored in the metric file nor change when the selected metric column is changed.

Show Subthresh Region Green If checked nodes failing a threshold test are shown in a blue-like green for positive values and negative values for an olive-like green for negative values.


It may be desirable to allow several, generic, namable thresholds that users could create as needed.

All thresholds should be stored with their associated maps.

User-Interface

Users have expressed a desire for control of thresholds using a slider bar. However, a slider bar may not provide the needed resolution to 'fine tune' the thresholding. Coupling the slider bar to a spin box may be a solution.

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