Previous chapters covered the process of image display in soft copy. This chapter covers primarily the process of hard-copy input and output. Although many imaging modalities have become purely digital with direct input to the image workstation, film still remains a common recording medium. The film must be digitized using some type of scanner or digitizer in order to be displayed on a soft-copy workstation. The term “digitizer” refers to any device that is used to convert a hard-copy transparency or reflective print to a string or array of digital values. The term “scanner” implies a digitizer where either the hard-copy input or detector is moved (scanned), but the term is often applied to the generic process of digitizing.
Although digital projection displays are in common use, the need still arises to print digital output data to a hard-copy medium, either paper or transparency. Film also remains as an efficient storage medium.
This discussion begins with device operation for hard-copy input and output. This is followed by a discussion of image quality as it relates to device selection. Finally, guidance is provided on how best to use hard-copy input and output devices.
Because digital projection displays are becoming a common means of presenting digital imagery to large groups, projection display quality parameters and image processing for those displays are discussed briefly.
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