Both Olympus E-PL9 and Samsung Galaxy Camera 4G have 16.0 MP resolution sensors but Olympus E-PL9's sensor is Four Thirds (17.3 x 13 mm ) and Samsung Galaxy Camera 4G's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Olympus E-PL9'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 Samsung Galaxy Camera 4G.
Below you can see the E-PL9 and Galaxy Camera 4G sensor size comparison.
As seen above, Olympus E-PL9 has a 8.0x Larger sensor area than Samsung Galaxy Camera 4G. 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.