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, Sony H20 has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the G16 and H20 sensor size comparison.
As seen above, Canon G16 has a 1.5x Larger sensor area than Sony H20. 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.