Canon SX60 HS has a
16.0MP 1/2.3 (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 6 processor. On the other hand, 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.
Below you can see the SX60 HS and SX20 IS sensor size comparison.
Canon SX60 HS and Canon SX20 IS have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon SX20 IS has 18% larger pixel area (2.34µm2 vs 1.98µm2) compared to Canon SX60 HS, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.