Canon G16 has a
12.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized BSI-CMOS sensor and features Digic 6 processor. On the other hand, Olympus 7040 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor.
Below you can see the G16 and 7040 sensor size comparison.
As seen above, Canon G16 has a 1.5x Larger sensor area than Olympus 7040. 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.