#### Description:

The routine adds two NDF  data structures pixel-by-pixel to produce a new NDF.

#### Parameters:

##### OUT = NDF (Write)
Output NDF to contain the sum of the two input NDFs.
The title for the output NDF. A null value will cause the title of the NDF supplied for Parameter IN1 to be used instead. [!]

#### Examples:

This adds the NDF called b to the NDF called a, to make the NDF called c. NDF c has the title "Co-added image".