And finally, are there sophisticated statistical methods that might resolve features of the signal that would otherwise be buried in the noise?

It is able to resolve features on the Sun less than 50 km across.

It hopes to resolve features on the Sun of the size of about 0.1 arcsec.

Of these, STM has been most commonly used in recent history due to its very high resolution and ability to resolve aperiodic features.

Rapid data collection has also made it practical to achieve the high sample densities necessary to resolve small or subtle features.

BGS has developed high-frequency sources and receivers for acoustic imaging that can resolve features down to about a metre.

Unfortunately, it can only resolve features at about the scale of the wavelength of the excitation light.

At the high magnification required to resolve micrometre-sized features, the technique can become prohibitively expensive in both time and money to perform.

For example, instruments that rely on optical interference cannot resolve features that are less than some fraction of the operating wavelength.

Using near-field optical techniques, researchers currently resolve features in the order of tens of nanometers in size.