Canon SD780 IS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Panasonic G85 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor .
One other difference between these two cameras that is worth mentioning is that Panasonic G85's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the SD780 IS and G85 sensor size comparison.
As seen above, Panasonic G85 has a 8.0x Larger sensor area than Canon SD780 IS. 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.