Both Canon XC10 and Casio EX-Z16 have 12.0 MP resolution sensors but Canon XC10's sensor is 1' (12.8 x 9.6 mm ) and Casio EX-Z16's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Canon XC10'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 Casio EX-Z16.
Below you can see the XC10 and EX-Z16 sensor size comparison.
As seen above, Canon XC10 has a 4.4x Larger sensor area than Casio EX-Z16. 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.