Spectral Imaging: Methods, Design, and Applications - Biomedical Optical Imaging Technologies: Design and Applications - page 155

Fig. 4.22 SKY classification
results. The human
metaphase was hybridized
with a SKY kit that contains
the appropriate combinatorial
labeling for each
chromosome (Applied
Spectral Imaging Inc., Migdal
HaEmek, Israel). The
measured spectral image is
analyzed, and the results are
shown in classification colors

entities. The methods require that the absorption spectra of the chromogens that
are used do not change significantly as a function of the local environment, a
condition that has been tested and found to be correct [ 66 ]. Other examples include
the analysis of pathological samples and even whole-animal imaging [ 76 ].
Another example of such an application is the observation of oxy- and deoxyhe-
moglobin which appears in different biomedical applications such as tissue vitality
and retinal ischemia diagnostics. The small changes in the spectrum of oxy- and
deoxyhemoglobin (Fig. 4.23 ) allow to determine the oxygen saturation level and
form a basis for these applications [ 19 , 23 , 49 , 52 ].
Other similar applications include industrial applications such as quality control
of drug manufacturing and others.

4.6.3 Observation of Spectra from Unknown Source

In some applications, the images that are measured contain spectra from an unknown
source. In such cases, prior knowledge of the spectral constituents does not exist, but
it is still possible to define spectral references from specific points that are identified
in the image and find similar spectra from the whole image. A typical example of
that kind exists in art studies as the one that was used to study the tints that were
used by Leonardo da Vinci for painting the Mona Lisa [ 77 ], see Fig. 4.24 .