kmcmilla@umn-d-ub.D.UMN.EDU (Ken McMillan) (01/06/88)
Could someone explain the differences between plotters, digitizers, and scanners? I understand how plotters work, but am at a loss as to how digitizers and scanners work. I hope this isn't to elementary for this group. :^) Please reply to me (kmcmilla@ub.d.umn.edu) or to this news group. As always T.i.A. ************************************************************************** Gee, if I push this reset button all these pretty lights start flashing, isn't that neat! **************************************************************************
davidsen@steinmetz.steinmetz.UUCP (William E. Davidsen Jr) (01/08/88)
In article <161@umn-d-ub.D.UMN.EDU> kmcmilla@ub.d.umn.edu (Ken McMillan) writes: | | Could someone explain the differences between plotters, digitizers, and | scanners? I understand how plotters work, but am at a loss as to how | digitizers and scanners work. A digitizer will allow you to convert a line image to a series of vectors. You (usually) manually place a crosshair mouse on the strating point and click, then the end point and click. The {start,end} pairs may then be processed. A scanner (again usually) rasterizes a line drawing by moving a point of light from left to right and storing data as a series of ones and zeros. The the paper (or light) is moved down to the next "line" and the process repeated. A good scanner produces about 300 dpi, the same as many laser printers. Some scanners, in hardware or software, allow grey scale by "dithering," or using a patters of dots to look like a shade of grey. Take a close look at a newspaper photo and you will see this effect. It's sometimes called "half toning," although I think a typographer might think there was a difference. Using dithering reduces the resolution. If a "real expert" wants to expand/clarify this, please do. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me