Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC
Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC
Anais do IHC'2001 - Departamento de Informática e Estatística - UFSC
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<strong>Anais</strong> <strong>do</strong> IHC’2001 - IV Workshop sobre Fatores Humanos em Sistemas Computacionais 299<br />
c) to set parameters for the computational part at two different moments in the<br />
computation: to start the method (initialisation) or to provi<strong>de</strong> information that is<br />
used to dynamically reconfigure parameter values (steering);<br />
d) to compose the object <strong>de</strong>lineation from "primitive" results selected among a<br />
number of possible <strong>de</strong>lineations generated automatically by the computational part;<br />
and<br />
e) to build a <strong>de</strong>dicated computational method, choosing the appropriate low-level<br />
image processing operations and the corresponding parameters.<br />
These aspects are complementary and found in combination in interactive<br />
segmentation methods found in the literature.<br />
4. Discussion<br />
Each aspect presented above has different implications to the ISM’s potential usability,<br />
<strong>de</strong>termining the accuracy and precision of the result to be achieved and the expected<br />
operation efficiency. When <strong>de</strong>signing and evaluating a new interactive method for image<br />
segmentation, it is important to carefully choose a combination of concepts, criteria and<br />
strategies that can help to improve not only its efficiency, but also its usability.<br />
With respect to the type of data input, we should investigate which are the most<br />
a<strong>de</strong>quate interaction styles and widgets for each situation concerning particular set of tasks<br />
and users. These are typical problems in HCI: interaction style selection – see<br />
Shnei<strong>de</strong>rman (1998), Newman and Lamming (1995) - and interaction object selection –<br />
see Bodart and Van<strong>de</strong>r<strong>do</strong>nckt (1994). The consequence of user input is directly related to<br />
low-level dialog <strong>de</strong>sign. Sequencing and availability of user actions (user interface syntax)<br />
have a large impact on the interaction simplicity – see Newman and Lamming (1995).<br />
Likewise, the computational component behavior can be ma<strong>de</strong> “intelligent” by anticipating<br />
actions or replacing user interventions for interaction efficiency. Finally, the user role in the<br />
process is related to high-level dialog <strong>de</strong>sign. It indicates the <strong>de</strong>cision level and the <strong>de</strong>gree of<br />
free<strong>do</strong>m the user has with respect to the segmentation goals, <strong>de</strong>termining how much and<br />
when the user can interfere in the segmentation process. The examples above represent a<br />
limited excursion into a territory that inclu<strong>de</strong>s many other possible perspectives such as<br />
recently explored by Ran<strong>de</strong>ll and Johnson (2001).<br />
References<br />
Bodart, F. and Van<strong>de</strong>r<strong>do</strong>nckt, J. (1994) “On the Problem of Selecting Interaction Objects”.<br />
In: Proc. BCS HCI'94, August 1994, Cambridge Univ. Press. p. 163-178.<br />
Gonzalez, R.C. and Woods (1993) R.E. “Image Segmentation”. In: __. Digital Image<br />
Processing. Addison-Wesley. p.413-481.<br />
Newman, W.M. and Lamming, M.G. (1995) Interactive Systems Design. Addison-Wesley.<br />
Olabarriaga, S. and Smeul<strong>de</strong>rs, A.W.M. (2001) “Interaction in the Segmentation of<br />
Medical Images: a Survey”. Medical Image Analysis, v.5. p.127-142.<br />
Ran<strong>de</strong>ll, R. and Johnson, C. (2001) “A Comparison of Methods for Analysing Human-<br />
Computer Interaction Failure in the Medical Domain”. Tech. Report. Univ. of Glasgow.<br />
http://www.dcs.gla.ac.uk/~rebecca/comparison.pdf<br />
Shnei<strong>de</strong>rman, B. (1998) Designing the User Interface, Addison-Wesley.