DICOM PS3.3 2019a - Information Object Definitions

### C.27.2 Points Macro

Table C.27-2 specifies the Attributes of the Points Macro.

Table C.27-2. Points Macro Attributes

Attribute Name

Tag

Type

Attribute Description

Number Of Surface Points

(0066,0015)

1

Specifies the number of points in the point set. See Section C.27.2.1.1.

Point Coordinates Data

(0066,0016)

1

Point Position Accuracy

(0066,0017)

3

A single standard deviation of the error for all the points' spatial positions. The units shall be the same as the units of the coordinate system in which the point coordinates are specified.

Mean Point Distance

(0066,0018)

3

The mean point distance of the point set.

It is given by the mean of the distances to the nearest neighbor over all points. The units shall be the same as the units of the coordinate system in which the point coordinates are specified.

Maximum Point Distance

(0066,0019)

3

The maximum distance of one point to its nearest neighbor. The units shall be the same as the units of the coordinate system in which the point coordinates are specified.

Points Bounding Box Coordinates

(0066,001A)

3

Two 3D locations defining the cuboid bounding box, parallel to the coordinate system axes, encompassing the point set.

Axis of Rotation

(0066,001B)

3

A 3D location that combined with Center of Rotation (0066,001C) specifies the preferred axis of rotation of this object.

Center of Rotation

(0066,001C)

1C

A 3D location defining the preferred center of rotation for this point set. Required if Axis of Rotation (0066,001B) is present. May be present otherwise.

#### C.27.2.1 Points Macro Attribute Descriptions

All Attributes within this Module containing points or vectors are in x-y-z order. If multiple elements are encoded, the ordering is x1,y1,z1,…,xn,yn,zn.

The points are in the coordinate system identified by the Frame of Reference UID (0020,0052). To map these points into the coordinate system of another SOP Instance a Spatial Registration Instance can be used.

##### C.27.2.1.1 Point Coordinates Data

When referencing individual points the index of the first point shall be 1.

DICOM PS3.3 2019a - Information Object Definitions