Controls visibility of an overlay embedded in the image
| Visual Basic |
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Public Property OverlayVisible( _ ByVal Overlay As Integer _ ) As Boolean |
DICOM defines up to 16 overlay planes embedded in an image, using group number 6000, 6002, 6004…601E, and these properties allow the developer to choose which to display. Each is a simple single bit mask, and is displayed if the appropriate OverlayVisible property is true, using the associated OverlayColour.
The source of the data for such overlays can be either unused bits in the pixel data, or separate elements, but this is handled internally by DicomObjects, and all such overlays are handled identically.
The OverlayIDs are numbered from 1 to 15, and so are related to the group numbers as follows:
OverlayID=(group number – 0x6000) / 2
Or put another way
Group number=OverlayID * 2 + 0x6000