Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!shelby!unix!quintus!arisia!sgi!shinobu!odin!odin.corp.sgi.com!portuesi From: portuesi@tweezers.esd.sgi.com (Michael Portuesi) Newsgroups: comp.graphics Subject: compositing digital images Message-ID: Date: 17 Aug 89 12:03:31 GMT Sender: news@odin.SGI.COM Organization: Silicon Graphics, Inc., Mtn. View, CA Lines: 27 I am looking for material on various methods used for compositing two digital images. I am aware of two methods for combining images. The first is the Porter-Duff matte algebra, which uses an alpha map for each image describing the opacity of each pixel in the image. (Compositing Digital Images, Computer Graphics, Vol. 18, No. 3, ACM, July 84). The second method I have seen is used by "Digital Darkroom", a Macintosh image processing program. It allows the user to selectively determine which grey values in the source image will be "painted" onto the target images, and what grey values in the image may be "painted" upon. The net effect is to allow the user to declare portions of both images as stencils. I am looking for other methods. Pointers to published material or short descriptions would be welcome. E-mail inquiries are invited; I will send summaries to interested parties. --M -- Michael Portuesi Silicon Graphics Computer Systems, Inc. portuesi@SGI.COM