This work focuses on estimating the information conveyed to a user by hyper
spectral image data. The goal is establishing the extent to which an increa
se in spectral resolution enhances the amount of usable information. Indeed
, a tradeoff exists between spatial and spectral resolution due to physical
constraints of multiband sensors imaging with a prefixed SNR. After descri
bing an original method developed for the automatic estimation of variance
and correlation of the noise introduced by hyperspectral imagers, lossless
interband data compression is exploited to measure the useful information c
ontent of hyperspectral data. In fact, the bit rate achieved by the reversi
ble compression process takes into account both the contribution of the "ob
servation" noise (i.e., information regarded as statistical uncertainty, bu
t whose relevance to a user is null) and the intrinsic information of radia
nce sampled and digitized through an ideally noise-free process. An entropi
c model of the decorrelated image source is defined and, once the parameter
s of the noise, assumed to be Gaussian and stationary, have been measured,
such a model is inverted to yield an estimate of the information content of
the noise-free source from the code rate. Results are reported and discuss
ed on both simulated and AVIRIS data.