Apparatus for determining a modification of a size of an object

A method of determining a modification of a size of an object, the method comprising the following steps:

• providing a first image data set showing the object at a first time and providing a second image data set showing the object at a second time being different from the first time,
• providing a first region of interest, in which the object shown in the first image data set is located, in the first image data set and providing a second region of interest, in which the object shown in the second image data set is located, in the second image data set,
• registering the first region of interest and the second region of interest with respect to each other, wherein a scaling value is generated by performing at least a scaling transformation for registering the first region of interest and the second region of interest with respect to each other, wherein the registering includes generating a first scaling value by performing the scaling transformation for registering the first region of interest onto the second region of interest and generating a second scaling value by performing the scaling transformation for registering the second region of interest onto the first region of interest,
• determining a modification value, which indicates the modification of the size of the object, depending on the generated scaling value, wherein the determining includes determining a first modification value, which indicates the modification of the size of the object, depending on the generated first scaling value and determining a second modification value, which indicates the modification of the size of the object, depending on the generated second scaling value,
• determining whether one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are similar with respect to a similarity measure, and
• outputting a signal if the similarity determination unit has determined that one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are not similar with respect to the similarity measure.

A computer program embodied on a non-transitory computer-readable medium for determining a modification of a size of an object, the computer program causing an apparatus to carry out a method, the method comprising the steps of:

• providing a first image data set showing the object at a first time and providing a second image data set showing the object at a second time being different from the first time,
• providing a first region of interest, in which the object shown in the first image data set is located, in the first image data set and providing a second region of interest, in which the object shown in the second image data set is located, in the second image data set,
• registering the first region of interest and the second region of interest with respect to each other, wherein a scaling value is generated by performing at least a scaling transformation for registering the first region of interest and the second region of interest with respect to each other, wherein the registering includes generating a first scaling value by performing the scaling transformation for registering the first region of interest onto the second region of interest and generating a second scaling value by performing the scaling transformation for registering the second region of interest onto the first region of interest,
• determining a modification value, which indicates the modification of the size of the object, depending on the generated scaling value, wherein the determining includes determining a first modification value, which indicates the modification of the size of the object, depending on the generated first scaling value and determining a second modification value, which indicates the modification of the size of the object, depending on the generated second scaling value,
• determining whether one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are similar with respect to a similarity measure, and
• outputting a signal if the similarity determination unit has determined that one of the first modification value and the second modification value and the inverse of the other of the first modification value and the second modification value are not similar with respect to the similarity measure.