Selection of the ROI is based on the previous model position, dynamic parameters and new ROI-image. Model knots are moved to better fitting positions with the goal of global energy minimization. Model fitting continues with activated optional parts. After fitting is good enough, a new image is loaded and the algorithm starts all over. Each model knot may contribute to several constraint functions.
Constraint functions take control over x and y coordinates of knots.
Special image processing energy functions apply the connection to the input image. Generalized edge detection is performed by the following energy functions. Behaves like the previous function but also takes the edge direction into account. The weight factors for the applied energy functions are initialized by empirically determined values. They are readjusted during model adaptation to achieve similar energy value ranges.