The Restricted Focus Viewer (RFV) is a computer based tool for tracking visual attention. It has been developed as an alternative to eye-tracking equipment, although it is not intended to be a replacement for such equipment. It is a cheap, non-intrusive and easy to set up system, that provides accurate data about which region of a stimulus is being looked at. This enables experimenters to determine which elements of a stimulus are being focused on at any time while a task is being performed. The RFV uses image blurring to restrict how much of a stimulus can be viewed in focus, while the computer mouse is used to shift the region of focus to different areas. Data from the RFV can also be replayed using the companion Replayer program.
This report describes Version 2.1 of the RFV. This is a totally new version of the RFV, and it is not compatible with any previous versions, including Version 2.0 (described in Jansen, 2000). Many new features have been added to this version, providing more flexibility for experimental designers. These include the experiment designer being able to control the layout of visual elements, and providing feedback to participants based on their responses. Enhancements have also been added to make the program more user friendly. For example, only a single input file is now needed for any given experiment, with the program able to modify the order of the experimental items for different participants.
Section 2 will discuss the system requirements for running the RFV and Replayer programs, including the tools required and the files that need to be downloaded. In Section 3, the RFV program is described in more detail, focusing specifically on how the program uses stimuli in tracking visual attention. This section will also include recommendations for setting RFV parameters that deal with stimulus presentation. Section 4 will look at the Input File that the experimenter must create in order to run an experiment using the RFV. Then, Section 5 describes the actually running the RFV program on a computer, and also discusses how the RFV user interacts with the program. Section 6 provides a tutorial that illustrates the features available in Version 2.1 of the RFV. In Section 7, the output data file produced by the RFV is described, and then in Section 8, the Replayer program that uses these output data files is examined to illustrate how data from the RFV can be replayed. The Replayer is a very useful tool for both data analysis, and also for generating retrospective verbal protocols. There is also an appendix which contains the specifications for the input file parameters.
The RFV has only recently been created, and the development process is
continuing. Therefore, any feedback on either of the RFV or Replayer
programs (or this User's Manual) would be welcome. The testing done with
the RFV to date has given promising results (Blackwell, Jansen & Marriott, 2000),
and it is hoped that other researchers will also find the RFV to be a useful
tool in understanding cognitive processes that involve visual attention, and
examining how people reason with visual stimuli.
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