Both Nikon L31 and Panasonic FH25 have 16.0 MP resolution sensors but Nikon L31's sensor is 1/2.3' (6.17 x 4.55 mm ) and Panasonic FH25's sensor is 1/2.3-inch (6.08 x 4.56 mm ).
Since Nikon L31's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Panasonic FH25.
Below you can see the L31 and FH25 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon L31 and Panasonic FH25 Cameras
Nikon L31 and Panasonic FH25 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.