Image presentation consistency is achieved by the DICOM Presentation State standard. This describes and communicates the presentation information (zoom, rotate, shutters, annotations etc.) that are applied to the image. The Presentation State has replaced the DICOM overlays. Overlays were created as bitmaps and exchanged as either as separate objects, archived and retrieved accordingly, or embedded in the images in the high (unused) bits of the pixel data, or as a separate bitmap in the header (Group 6000). The Presentation State includes the zoom factor, window width and level value, displayed overlays, masks and shutters and the image orientation parameters. Presentation States are defined for both grayscale and color. The information is exchanged as a separate DICOM object, with its own SOP Class, i.e. Presentation State SOP Class, which in addition to the image parameters also contains a reference to the image(s), or even series the presentaiton state applies to. |