Digitizer resolution, dynamic range

To evaluate the image quality of the processing system, one can determine classical parameters like spatial resolution, contrast resolution, dynamic range, local and global distortion. Guidelines for film digitization procedures have been well described now. Furthermore, a physical standard film for both equipment assessment and digitization calibration and control, will be available in a next future (4). 

Fig. 10.8. Different types of image distortions. The small circles mark the reference positions in an ideal 2-D grid, the crosses indicate the measured positions. Depending on their origin, these errors are either temporary, permanent or of dynamic nature. Hence, the dynamic behavior of the scan system has to be taken into account when performing a lateral calibration. The scan speed may even have a greater influence on the actual correction factor than the scan range. Further to be considered are the digital resolution (in z-direction) and the number of pixels (in x-y-direction).

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