Nikon B600 has a
16.0MP 1/2.3 (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Olympus SP-590 UZ has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the B600 and SP-590 UZ sensor size comparison.
Nikon B600 and Olympus SP-590 UZ 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.