In this note, the imaging properties of a CCD x-ray film scanner were
investigated. The relationship between optical density and the logarit
hm of output pixel value provides information on die linearity of the
system. The resolution properties of the scanner can be characterized
by the presampling modulation transfer function which was calculated f
rom a set of line spread functions with various alignments relative to
die sampling grid. Our results show that the scanner is linear up to
2.0 optical density units, which leads to restrictions in digitizing x
-ray films with higher optical density. The measured MTF shows the goo
d spatial resolution of the CCD scanner which is demonstrated on an ex
ample.