Blending Lookup Table Descriptor Attribute
| Tag | (0028,1407) |
|---|---|
| Type | Conditionally Required (1C) |
| Keyword | BlendingLookupTableDescriptor |
| Value Multiplicity | 3 |
| Value Representation | Unsigned Short (US) |
Specifies the format of Blending Lookup Table Data (0028,1408) in this Sequence Item.
The second value (first stored pixel value mapped) shall be zero.
See Section C.7.6.23.5 for further explanation.
Required if Blending LUT 2 Transfer Function (0028,140D) is TABLE.
Section C.7.6.23.5
C.7.6.23.5 Blending LUT Descriptor
The three values of the Blending Lookup Table Descriptor (0028,1407) describe the format of the data in Blending Lookup Table Data (0028,1408).
The first value is the number of entries in the lookup table. When the number of table entries is equal to 65,536 (216), then this value shall be 0. The number of entries shall be equal to the number of possible values in the input.
Note
For example, for 8 bit input to the Blending LUT the tables must have 256 entries, while for 16 bit input to the Blending LUT the tables must have 65,536 entries.
The second value is the first input value mapped, and shall always be 0 for an Blending LUT. This input value is mapped to the first entry in the LUT. Subsequent input values are mapped to the subsequent entries in the LUT Data up to an input value equal to number of entries + first value mapped - 1 that is mapped to the last entry in the LUT Data. There are no input values greater than number of entries - 1.
The third value specifies the number of bits for each entry in the LUT Data. This value shall be between 8 and 16, inclusive. The LUT Data shall be stored in a format equivalent to 16 bits allocated where the high bit is equal to bits stored - 1, where bits stored is the third value.