Both Panasonic TS6 and Olympus E-PM2 have 16.0 MP resolution sensors but Panasonic TS6's sensor is 1/2.33" (6.08 x 4.56 mm ) and Olympus E-PM2's sensor is Four Thirds (17.3 x 13 mm ).
Since Olympus E-PM2'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 TS6.
Below you can see the TS6 and E-PM2 sensor size comparison.
As seen above, Olympus E-PM2 has a 8.1x Larger sensor area than Panasonic TS6. 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.