rigid transformation is for same modality(CT-CT) nad it can only perform translation, rotation and scaling translation. whereas non rigid for multimodality and it can do streching and shriking too. it use demon algorithm .
A rigid motion is a transformation in geometry that preserves the shape and size of a figure. This means that distances between points and angles remain unchanged during the transformation. Common types of rigid motions include translations, rotations, and reflections. Since the original figure and its transformed image are congruent, rigid motions do not alter the overall structure of the figure.
A dilation is not a basic rigid motion because it alters the size of a figure while maintaining its shape, rather than preserving distances between points. Rigid motions, such as translations, rotations, and reflections, only change the position or orientation of a figure without affecting its dimensions. In contrast, dilations involve scaling, which can either enlarge or reduce a figure, thus not satisfying the criteria of preserving lengths and angles.
Rigid is immovable, unbending. Semi-rigid can move in a limited way.
In 2 dimensional space it is a translation vector which is a 2x1 column vector.
A translation is a type of rigid motion, which means it preserves distances and angles between points. In a translation, every point in a figure moves the same distance and direction. Rigid motions also include rotations and reflections.
rigid transformation is for same modality(CT-CT) nad it can only perform translation, rotation and scaling translation. whereas non rigid for multimodality and it can do streching and shriking too. it use demon algorithm .
dilation (APEX)
Stretch
Movement of a shape can involve flexing - for example, a square frame being flexed into a rhombus. Rigid motion excludes such motion: the shape of the moving object does not change.
A rigid motion transformation is one that preserves distances and angles between points in a geometric shape. Anything that involves changing the size or shape of the object, such as scaling or shearing, would not describe a rigid motion transformation.
The key difference between a particle and a rigid body is that a particle can undergo only translational motion whereas a rigid body can undergo both translational and rotational motion
Rigid motion
Planets
Translation, rotation and curvilinear motion
Edward Washington Suppiger has written: 'An analysis of the motion of a rigid body' -- subject(s): Dynamics, Rigid, Rigid Dynamics
Translation, rotation and curvilinear motion