Initializes a new instance of the AnnotationIdentifier class.
sopInstanceUID
The SOP Instance UID of the data set to be associated with the annotation.
objectNumber
A number identifying one of the annotations associated with the sopInstanceUID.
A sopInstanceUID can have more than one annotation container. The objectNumber identifies the annotation container For example, the first annotation container has an objectNumber equal to 1. The second annotation container has an objectNumber equal to 2.