The Shutter transformation provides the ability to exclude the perimeter outside a region of an image. A gray level may be specified to replace the area under the shutter.
One form of this transformation uses the Display Shutter Module as used in the X-Ray Angiography Image Storage SOP Class, though it may be applied to any Image Storage SOP Instance, including single frame images.
Another form uses a bit-mapped overlay to indicate arbitrary areas of the image that should be excluded from display by replacement with a specified gray level, as described in the Bitmap Display Shutter Module.
Notes: 1. Since annotations follow the shutter operation in the pipeline, annotations in shuttered regions are not obscured and are visible.
2. Any shutter present in the referenced image object is ignored (i.e. not applied).