Canon SX20 IS has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Panasonic FZ100 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CMOS sensor and features Venus Engine FHD processor.
Below you can see the SX20 IS and FZ100 sensor size comparison.
Canon SX20 IS and Panasonic FZ100 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.