Pentax WG-3 has a 16.0MP 1/2.3" (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Canon G5 X has a 20.0MP 1" (13.2 x 8.8 mm ) sized BSI-CMOS sensor and features DIGIC 6 processor.
Below you can see the WG-3 and G5 X sensor size comparison.
As seen above, Canon G5 X has a 4.1x Larger sensor area than Pentax WG-3. 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.