All deformable template approaches require the manual construction of example data sets with which to build the parametric model of shape and grey-level profile. The parameters of this boundary can be specified using the Model Parameters dialogue box, and these must remain fixed across any set of data intended to construct a single model. The selection of a particular mark-up type p axis r axis initiates the process of mark-up in the selected Tv. Mark-up requires a three button mouse. The user must define how many boundary boints are required and may place them where he/she wishes, provided that each mark-up is consistent. Template models cannot deal with redefinition of point order within a training set.
For p axis mark up, click and drag the left mouse button to establish a baseline. Now click the left button and drag again to define a rectangular boundary box around the required structure. At this point a set of parallel lines will be drawn across the region, one of which is blue. This blue line can be used as a guide for the location of a boundary point. Mark-up using the r axis scheme is similar, specifying the left and right points on the main axis and continuing in an anti-clockwise direction filling in the missing points.
This button takes the outer profile (if present) and converts it to a polygonal boundary for use as the region of interest in any Tv.
This button takes the inner profile (if present) and converts it to a polygonal boundary for use as the region of interest in any Tv.