Nikon S2900 has a
20.0MP 1/2.3' (6.17 x 4.55 mm ) sized CCD sensor and features Expeed C2 processor. On the other hand, Panasonic FH20 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Nikon S2900's sensor provides 6MP more than Panasonic FH20's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the S2900 and FH20 sensor size comparison.
Nikon S2900 and Panasonic FH20 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.