Added functor documentation.

    int m_defaultValue;

  public:

    /**

     * Default Constructor

     * @param offset       The minimum value of the input cube's pixel type

     * @param defaultValue Value used for pixels that are not taken from a cube

     */

    CopyPixelsFunctor(int offset, int defaultValue) {

      m_offset = offset;

      m_defaultValue = defaultValue;

    }

    /**

     * Copies DN's from the input cube to the tracking cube, subtracts the old offset, and adds

     * the new offset to each pixel.

     *

     * @param in  Input cube

     * @param out Mosaic cube

     */

    void operator()(Buffer &in, Buffer &out) const {

      for (int i = 0; i < in.size(); i++) {

        if (in[i] == (float) m_defaultValue) {