portuesi@tweezers.esd.sgi.com (Michael Portuesi) (08/17/89)
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
portuesi@tweezers.esd.sgi.com (Michael Portuesi) (08/17/89)
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 responses are invited; I will send summaries to interested parties. --M -- Michael Portuesi Silicon Graphics Computer Systems, Inc. portuesi@SGI.COM
MICHAL@kuhub.cc.ukans.edu (Merlin The Magician) (08/25/89)
In article <PORTUESI.89Aug17130432@tweezers.esd.sgi.com>, portuesi@tweezers.esd.sgi.com (Michael Portuesi) writes: > 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). I have a working system like so based on the Porter-Duff paper and the Porter'85. Runs on IRIS and BSD 4.3 Unix on VAX 11/780. > 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. There was an article in the March 1989 issue of IEEE Computer Graphics and Applications (I believe) about some folks from Japan. More information was stored in the images (well, more then in the Porter-Duff alpha channel) but it allowed for such operations as streching or compressing images (apart from compositing). I don't quite remember more details from it. > > I am looking for other methods. Pointers to published material or > short descriptions would be welcome. E-mail responses are invited; I > will send summaries to interested parties. > > --M > Don't know of any other. > -- > Michael Portuesi Silicon Graphics Computer Systems, Inc. > portuesi@SGI.COM -- Merlin The Magician +------------------------------+----------------------------------------------+ | Michal Chmielewski \ The inherent vice of capitalism is the | | Academic Computing Services \ unequal sharing of blessings; the | | University of Kansas \ inherent virtue of socialism is the | | Lawrence, KS 66045 \ equal sharing of miseries. | | Internet: michal@kuhub.cc.ukans.edu - Winston Churchill | | BitNet : michal@ukanvax.bitnet \ | +-------------------------------------+---------------------------------------+