Detection of pose changes for spatial objects from projective images

Numerous fields of application effort the detection of pose changesfor 3 dimensional objects in six degrees of freedom (6 DoF). Automaticprocedures that exploit 2D images for the detection of pose changescan be used for example for tracking object movements, for qualitycontrol or for the verification of the alignment of patients in radiationtreatment devices. In this contribution we present two differentsolutions for the detection of pose changes that base on the comparisonof two 2D images resulting from the projection of an object in thenew pose and a 3D volume of the same object in a known referencealignment. Whereas for the first solution we use an object wherewe can clearly extract landmarks useable as reference positions forthe determination of the object’s alignment, we provide a secondsolution for objects where these landmarks cannot be extracted, whichis involved automatically if necessary. In this case grey value basedpose estimation is conducted by registering the computationally projectedreference 3D volume to the 2D images. As reference data for the objectwith known alignment, CT slices will be used, as they are providedfor the alignment of patients in radiation treatment devices. TwoX-ray images of the same object in an unknown pose can then be comparedto the reference data to determine the respective pose change, whichmay consist of 3 rotations and 3 translations. Using both approachesto determine patient misalignments in treatment devices shows, thatboth methods result in highly accurate pose detections and that thesecond method, despite being less accurate and more time consuming,is an appropriate solution in cases where landmark detection fails.     «

Numerous fields of application effort the detection of pose changesfor 3 dimensional objects in six degrees of freedom (6 DoF). Automaticprocedures that exploit 2D images for the detection of pose changescan be used for example for tracking object movements, for qualitycontrol or for the verification of the alignment of patients in radiationtreatment devices. In this contribution we present two differentsolutions for the detection of pose changes that base on the comparisonof two 2D images resul...     »