Both Olympus TG-3 and Fujifilm F550 EXR have 16.0 MP resolution sensors but Olympus TG-3's sensor is (1/2. ) and Fujifilm F550 EXR's sensor is 1/2-inch (6.4 x 4.8 mm ).
Since Fujifilm F550 EXR'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 Olympus TG-3.
Below you can see the TG-3 and F550 EXR sensor size comparison.
As seen above, Fujifilm F550 EXR has a infx Larger sensor area than Olympus TG-3. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.