Olympus Tough-3000 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor. On the other hand, Sony TX20 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features BIONZ processor.
Below you can see the Tough-3000 and TX20 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus Tough-3000 and Sony TX20 Cameras
Olympus Tough-3000 and Sony TX20 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.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Olympus Tough-3000
or the
Sony TX20 ,
including hyperfocal distance.