DICOM PS3.3 2018d - Information Object Definitions

C.7.6.11 Display Shutter Module (Current)
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#### C.7.6.11 Display Shutter Module

The Display shutter is a geometric mask consisting of one or more combined shapes that may be applied on the image for presentation purposes in order to neutralize the display of any of the pixels located outside of the shutter shape. Geometry of the shutter is specified with respect to a row and column coordinate system where the origin is the upper left hand pixel. This origin is specified by the values 1,1 for row/column. A row coordinate represents a row spacing (vertical) and a column coordinate represents a column spacing (horizontal). Up to three different shutter shapes may be used and superimposed.

The manner in which the display area is neutralized (black-out, gray, or other means) is defined by the Attribute Shutter Presentation Value (0018,1622), or undefined if this Attribute is absent or empty.

Table C.7-17. Display Shutter Module Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Include Table C.7-17a “Display Shutter Macro Attributes” |

Table C.7-17a. Display Shutter Macro Attributes

Attribute Name | Tag | Type | Attribute Description
--- | --- | --- | ---
Shutter Shape | (0018,1600) | 1 | Shape(s) of the shutter defined for display. Enumerated Values: RECTANGULAR CIRCULAR POLYGONAL This multi-valued Attribute shall contain at most one of each Enumerated Value. When multiple values are present, and the shutter is applied to a displayed image, then all of the shapes shall be combined and applied simultaneously, that is, the least amount of image remaining shall be visible (unoccluded). See Figure C.7-4b.
Shutter Left Vertical Edge | (0018,1602) | 1C | Required if Shutter Shape (0018,1600) is RECTANGULAR. Location of the left edge of the rectangular shutter with respect to pixels in the image given as column.
Shutter Right Vertical Edge | (0018,1604) | 1C | Required if Shutter Shape (0018,1600) is RECTANGULAR. Location of the right edge of the rectangular shutter with respect to pixels in the image given as column.
Shutter Upper Horizontal Edge | (0018,1606) | 1C | Required if Shutter Shape (0018,1600) is RECTANGULAR. Location of the upper edge of the rectangular shutter with respect to pixels in the image given as row.
Shutter Lower Horizontal Edge | (0018,1608) | 1C | Required if Shutter Shape (0018,1600) is RECTANGULAR. Location of the lower edge of the rectangular shutter with respect to pixels in the image given as row.
Center of Circular Shutter | (0018,1610) | 1C | Required if Shutter Shape (0018,1600) is CIRCULAR. Location of the center of the circular shutter with respect to pixels in the image given as row and column.
Radius of Circular Shutter | (0018,1612) | 1C | Required if Shutter Shape (0018,1600) is CIRCULAR. Radius of the circular shutter with respect to pixels in the image given as a number of pixels along the row direction.
Vertices of the Polygonal Shutter | (0018,1620) | 1C | Required if Shutter Shape (0018,1600) is POLYGONAL. Multiple Values where the first set of two values are: row of the origin vertex\column of the origin vertex Two or more pairs of values follow and are the row and column coordinates of the other vertices of the polygon shutter. Polygon shutters are implicitly closed from the last vertex to the origin vertex and all edges shall be non-intersecting except at the vertices.
Shutter Presentation Value | (0018,1622) | 3 | A single gray unsigned value used to replace those parts of the image occluded by the shutter, when rendered on a monochrome display. The units are specified in P-Values, from a minimum of 0000H (black) up to a maximum of FFFFH (white). ### Note The maximum P-Value for this Attribute may be different from the maximum P-Value from the output of the Presentation LUT, which may be less than 16 bits in depth.
Shutter Presentation Color CIELab Value | (0018,1624) | 3 | A color triplet value used to replace those parts of the image occluded by the shutter, when rendered on a color display. The units are specified in PCS-Values, and the value is encoded as CIELab. See Section C.10.7.1.1.

Figure C.7-1, Figure C.7-2, Figure C.7-3, Figure C.7-4 and Figure C.7-4b illustrate the values of coordinate Attributes for 1:1 aspect and 2:1 aspect ratio images with rectangular and circular display shutters applied.

Figure C.7-1. Rectangular Display Shutter (1:1 aspect ratio image)

Figure C.7-2. Rectangular Display Shutter (2:1 aspect ratio images as they would appear before interpolation for display)

Figure C.7-3. Circular Display Shutter (1:1 aspect ratio image)

Figure C.7-4. Circular Display Shutter (2:1 aspect ratio images as they would appear before interpolation for display)

Figure C.7-4b illustrates the combined application of rectangular and circular display shutters to show the least amount of visible image.

Figure C.7-4b. Combined Rectangular and Circular Display Shutter

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DICOM PS3.3 2018d - Information Object Definitions