Canon SX30 IS has a 14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Nikon P7100 has a 10.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized CCD sensor and features Expeed C2 processor.
Below you can see the SX30 IS and P7100 sensor size comparison.
As seen above, Nikon P7100 has a 1.5x Larger sensor area than Canon SX30 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.