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, Leica V-Lux 2 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CMOS sensor .
Below you can see the SX20 IS and V-Lux 2 sensor size comparison.
Canon SX20 IS and Leica V-Lux 2 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.