Imagery data are represented by positive digital numbers which vary from 0 to (one less than) a selected power of 2. The maximum number of brightness levels available depends on the number of bits used in representing the energy recorded.This range corresponds to the number of bits used for coding numbers in binary format. Thus, if a sensor used 8 bits to record the data, there would be 28=256 digital values available, ranging from 0 to 255.However, if only 4 bits were used, then only 24=16 values ranging from 0 to 15 would be available.
The radiometric resolution of an imaging system describes its ability to discriminate very slight differences in energy The finer the radiometric resolution of a sensor, the more sensitive it is to detecting small differences in reflected or emitted energy. The illustration on the right is the same but presented in 8 bits or 256 shades of grey, which provides more details.
This collage shows the difference in the level of detail between the two representations.
his document discusses the way radiometric dating and stratigraphic principles are used to establish the conventional geological time scale.
It is not about the theory behind radiometric dating methods, it is about their , and it therefore assumes the reader has some familiarity with the technique already (refer to "Other Sources" for more information).
The example used here contrasts sharply with the way conventional scientific dating methods are characterized by some critics (for example, refer to discussion in "Common Creationist Criticisms of Mainstream Dating Methods" in the Age of the Earth FAQ and Isochron Dating FAQ).
A common form of criticism is to cite geologically complicated situations where the application of radiometric dating is very challenging.The rate of decay (given the symbol λ) is the fraction of the 'parent' atoms that decay in unit time.For geological purposes, this is taken as one year.Many people assume that the dates scientists quote of millions of years are as reliable as our knowledge of the structure of the atom or nuclear power.And radioactive dating is so shrouded with mystery that many don’t even try to understand how the method works; they just believe it must be right.These are often characterised as the norm, rather than the exception.