In the case of the sphere, for instance, whose radius is R, the area of the section at distance x from the centre is lr(R 2 -x 2), which is a quadratic function of x; the values of So, Si, and S2 are respectively o, 7rR 2, and o, and the volume is therefore s.
The fusion of the data from LR images into a higher resolution image is then carried out through thin plate spline interpolation.
If the official receiver is aware of the title number it should be quoted in all correspondence with the LR.