rbarr@su19o.uucp (Rick Barr) (09/24/90)
A customer has requested that we deliver data in CCITT group 4 graphics format. Anybody know what this is? Rick Barr (407) 727-6111
paul@images1.Waterloo.NCR.COM (Paul J. Latimer) (09/25/90)
In article <4368@trantor.harris-atd.com>, rbarr@su19o.uucp (Rick Barr) writes: > A customer has requested that we deliver data in CCITT group 4 graphics > format. Anybody know what this is? > CCITT is the governing body for FAX standards. They developed Group III compression (both 1- and 2-dimensional) for FAX transmission. Group IV is also used, but usually only over an error-free medium (like LAN's, ISDN, most disk devices, etc. that have error-detecting and correcting facilities). The CCITT image compressions formats are public domain and commonly used for image starage and exchange. However, it does not define a file format. You probably want to find this out from your customer. I would suggest TIFF which is very easy to use and is very common. -- ==================================================================== Paul J. Latimer, Phone: (519)884-1710 FAX: (519)884-0610 Engineering Department, E-Mail: Paul.J.Latimer@Waterloo.NCR.COM NCR Canada Ltd., 580 Weber St. N., Waterloo, Ontario, Canada N2J 4G5
jtc@van-bc.wimsey.bc.ca (J.T. Conklin) (09/27/90)
In article <4368@trantor.harris-atd.com> rbarr@su19o.UUCP (Rick Barr) writes: >A customer has requested that we deliver data in CCITT group 4 graphics >format. Anybody know what this is? They are probably requesting raw CCITT T.6 encoded data, as is transmitted between two Group 4 facsimile machines. The T.6 specification only specifies transmitted data; it doesn't dictate how this should be represented in a file, as image storage is outside its domain. When dealing with images of this nature, I prefer to encapsulate them in TIFF files, which have the necessary tags to specify image size, image resolution, bit order, photometric interpretation, etc... ---jtc -- J.T. Conklin UniFax Communications Inc. ...!{uunet,ubc-cs}!van-bc!jtc, jtc@wimsey.bc.ca
andrea@sdd.hp.com (Andrea K. Frankel) (09/29/90)
In article <2157@van-bc.wimsey.bc.ca> jtc@van-bc.wimsey.bc.ca (J.T. Conklin) writes: >In article <4368@trantor.harris-atd.com> rbarr@su19o.UUCP (Rick Barr) writes: >>A customer has requested that we deliver data in CCITT group 4 graphics >>format. Anybody know what this is? > >They are probably requesting raw CCITT T.6 encoded data, as is >transmitted between two Group 4 facsimile machines. The T.6 >specification only specifies transmitted data; it doesn't dictate how >this should be represented in a file, as image storage is outside its >domain. > >When dealing with images of this nature, I prefer to encapsulate them >in TIFF files, which have the necessary tags to specify image size, >image resolution, bit order, photometric interpretation, etc... Another possibility is that the customer is a DOD contractor or subcontractor who is required to have CALS conformant files. The CALS program selected CCITT group 4 for interchange of raster information, and they defined their own file header for size, resolution, etc. See MIL-R-28002 for details. Unfortunately, though, it's only bilevel at this time. Andrea Frankel, Hewlett Packard, San Diego Technical Graphics Div., R&D Lab "wake now! Discover that you are the song that the morning brings..." ______________________________________________________________________________ Internet : andrea@sdd.hp.com (or andrea%hp-sdd@nosc.mil or @ucsd.edu) UUCP : {hplabs|nosc|hpfcla|ucsd}!hp-sdd!andrea CSNET : andrea%hp-sdd@hplabs.csnet USmail : 16399 W. Bernardo Drive - Mailstop 61U65, San Diego CA 92127-1899 Voice : (619) 592-4664