The Image Processing Workbench is a Unix-based image processing software system. The system was written by Jim Frew, with contributions from Jeff Dozier, J. Ceretha McKenzie, and others at the University of California, Santa Barbara. The software is portable among Unix systems and is freely distributable. The name Image Processing Workbench reflects the influence the Unix system had on the design of IPW, since an early version of Unix was called the `Programmer's Workbench'.
Individual Unix and IPW programs are "tools" which may be used together to perform more complicated operations. IPW is a set of programs, written in C, that form an extension of Unix. Therefore, IPW programs can be used in combination with Unix programs, and IPW has no need to duplicate basic Unix functions such as file management and command interpretation.
Unix programs are executed by typing the name of the program as a command to the shell. Parameters are specified on the command line, rather than in response to user prompts. The command syntax for IPW is patterned after the proposed standard for Unix system commands.
In Unix and IPW most input and output are on preconnected channels, the standard input (stdin) and the standard output (stdout). "Pipes" connect the standard output of one command to the standard input of the next. The use of pipes avoids intermediate files and speeds the execution time since the second program in the pipeline may start running as soon as output from the first program begins.
IPW consists of programs for generic image processing operations, applications programs, and interfaces to public domain display programs. Since the Unix shell is programmable, many IPW commands are written as Unix shell programs (commonly called "shell scripts"), that combine IPW and shell commands to perform specific image processing tasks.