Image SOP Instances, or frames from multi-frame SOP Instances, to be displayed in an Image Box may be identified either directly by the Referenced Image Sequence (0008,1140), or indirectly through the Referenced Presentation State Sequence (0008,9237).
Referenced Image Sequence (0008,1140) is permitted to be zero length, indicating an empty Image Box.
Note: 1. The recommended display color for an empty Image Box is specified by Empty Image Box CIELab Value (0072,0421).
2. When displaying a standard template such as a dental full mouth series, an empty image box may be used to indicate that the corresponding view was not taken.
If images are identified indirectly through the Referenced Presentation State Sequence (0008,9237), all of the image frames identified in the top level Referenced Series Sequence (0008,1115) attribute shall be displayed. For images identified indirectly through a Blending Presentation State SOP Instance, all the image frames for which the Blending Position (0070,0405) value is UNDERLYING shall be displayed, with the relevant SUPERIMPOSED images blended as necessary.
If images are to be displayed, the number of frames referenced for display shall be consistent with the value of Image Box Layout Type (0072,0304). If the value of Image Box Layout Type is SINGLE, only a single frame shall be referenced, either directly or indirectly; if the value is CINE, only a single multi-frame SOP Instance shall be referenced.
If the value of Image Box Layout Type is STACK, more than one SOP Instance or frame may be referenced, and the frames constitute a stack to be displayed in the Image Box. For frames identified by the Referenced Image Sequence, the order of stepping through the stack shall be the order of Image SOP Instance references in that Sequence. If multiple frames are selected in Referenced Frame Number (0008,1160), those frames shall be stepped through in the order of their listing in that attribute, within the order of display of their Image SOP Instance.
For a stack whose frames are selected indirectly through an Item of the Referenced Presentation State Sequence, the order of stepping through the stack shall be the order of SOP Instance references in the Referenced Series Sequence (0008,1115) of the referenced Presentation State. For a referenced Blending Softcopy Presentation State, this shall be the Referenced Series Sequence within the Blending Sequence (0070,0402) for which the Blending Position (0070,0405) value is UNDERLYING.
Notes: 1. Display of images using Blending Softcopy Presentation State must use indirect SOP Instance reference through the Referenced Presentation State Sequence (0008,9237) at the top level of Structured Display Image Box Sequence (0072,0422) Item, and cannot use the Referenced Presentation State Sequence within an item of the Referenced Image Sequence (0008,1140).
2. A Blending Presentation State that references a blending of a single underlying frame and a single superimposed frame may be associated with a SINGLE Image Box Layout.
3. A reference to a single display frame, either directly through Referenced Image Sequence or indirectly through Referenced Presentation State Sequence, may be associated with either a STACK or a CINE Image Box Layout as a degenerate case.
4. There is no requirement for the pixel matrix sizes of the images in the stack, or the image display area as selected by referenced Presentation State SOP Instances, to be identical, nor for the referenced images to be of the same SOP Class.
5. Referenced Presentation States are an initial presentation control. The rendering Application Entity might allow a user to interactively enable/disable graphic layers, or change the zoom, rotation, window width / window level, or other presentation controls. Any such Application Entity functionality is beyond the scope of the Standard.