0,8
0.6
0.4
0,2
a
of
C = 0.05
c1=0 ..
1
c2=0.02 H-'
I/c
1'1"~
' Ei
r2 Microscopy and Imaging Systems
69
Fig. 10. Intensity profile of two
signals having different intensities. Their separation is close to
the resolution limit of the standard CCD. However, due to the
reduced signal contrast c of only
0.05 the camera signal does not
resolve the two peaks (cl=O). The
mega pixel camera provides a
slightly better result (relative
contrast c2 of camera signal is
0.02)
contour the spots of region A will be interpreted as two individual spots
although their intensity profile does not exhibit a second peak.
Conclusion
A FISH imaging system is more than the sum of its components. However,
one of the components will always define the ultimate limit. It is of particular importance to include the FISH preparation as a major (if not the
major) limiting component in the imaging process. Resolution and image
quality is determined by the signal to background ratio, which is in most
practical situations limited by the sample itself. No imaging system is able
to add information to the raw image data. It can just help to visualize the
information and remove unwanted distracting information. Moderately
priced standard hardware components can provide completely satisfactory results if the software of the imaging system ensures that they are
used to their full potential. Ironically, more sophisticated equipment
can even compromise the results for merely practical reasons (as was
the case in early mega pixel CCD cameras that did not provide a sufficiently fast display rate for precise focussing). The most important advice
to be given is to check any imaging system under realistic conditions with
the same type of preparations that the system will ultimately be used for.
The worst thing to do is to make a decision based on the specification
sheets of the system's individual hardware components.
0.6
0.4
0,2
a
of
C = 0.05
c1=0 ..
1
c2=0.02 H-'
I/c
1'1"~
' Ei
r2 Microscopy and Imaging Systems
69
Fig. 10. Intensity profile of two
signals having different intensities. Their separation is close to
the resolution limit of the standard CCD. However, due to the
reduced signal contrast c of only
0.05 the camera signal does not
resolve the two peaks (cl=O). The
mega pixel camera provides a
slightly better result (relative
contrast c2 of camera signal is
0.02)
contour the spots of region A will be interpreted as two individual spots
although their intensity profile does not exhibit a second peak.
Conclusion
A FISH imaging system is more than the sum of its components. However,
one of the components will always define the ultimate limit. It is of particular importance to include the FISH preparation as a major (if not the
major) limiting component in the imaging process. Resolution and image
quality is determined by the signal to background ratio, which is in most
practical situations limited by the sample itself. No imaging system is able
to add information to the raw image data. It can just help to visualize the
information and remove unwanted distracting information. Moderately
priced standard hardware components can provide completely satisfactory results if the software of the imaging system ensures that they are
used to their full potential. Ironically, more sophisticated equipment
can even compromise the results for merely practical reasons (as was
the case in early mega pixel CCD cameras that did not provide a sufficiently fast display rate for precise focussing). The most important advice
to be given is to check any imaging system under realistic conditions with
the same type of preparations that the system will ultimately be used for.
The worst thing to do is to make a decision based on the specification
sheets of the system's individual hardware components.