One height map frame with multiple rows may specify the height map across all the referenced frames only if the Height Map Segmentation is specified for multiple, equally spaced parallel frames of the referencedderivation image. The multiple frames of the derivation image may be encoded in a single multi-frame SOP Instance, or in a Series of single frame or multi-frame SOP Instances, as long as the frames are parallel, equally sized, and equally spaced.
The segmentation might not extend across all of the frames of the SOP Instances referenced in the Derivation Image Functional Group. All the frames that are segmented shall be enumerated.
Note
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A height map with multiple rows might be used for segmentation of a cube-scan OPT image. Referenced OPT images with equal slice spacing might have the Ophthalmic Volumetric Properties Flag (0022,1622) value YES.
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The height map may be specified for a subset of frames of the derivation image. The frames in the subset are not necessarily adjacent, e.g., if only even numbered frames are segmented. As long as the referenced frames are equally spaced, a single height map frame with multiple rows may specify the height map across all the referenced frames
The value of Rows (0028,0010) of the Height Map Segmentation shall equal the number of frames referenced in the derivation image. The orientation of a Height Map Segmentation frame with more than one row is thus orthogonal to the orientation of thederivation image frames. See example in Figure C.8.20.5-3.
