Archive for October 25th, 2011
Bernice E. Rogowitz covered fundamentals in human perception and cognition, and discussed how they apply to visualization. She covered a huge array of topics, ranging from the pupil being partially responsible for our depth perception, all the way to color theory and how it relates directly to the biology of the human eye.
The presentation had a great flow, starting at a very high level to give everyone an idea of what questions they would be able to answer at the end. As the talk progressed, she covered detailed biological details of the human eye, and progressed to the intersection of perceptual issues and computer science.
In the biological portion, we learned that there are five layers of cells in the retina, each responsible for different tasks. Much of the interesting stuff happens at the very beginning (photoreceptor distribution) and then further into the process at the ganglion cells. She went over how lateral inhibition is caused by the spatial distribution of the photoreceptors connected to a single ganglion cell, and how this is the reason for several of the optical illusions we perceive. She did a great job of explaining the connections between biology and perceptual issues.
Cultural differences were also addressed. The eye movements we have are actually learned when we learn how to read. Cultures with different reading directions have substantially different reading directions.
The section on the Striate Cortex was especially interesting. This is the first time in the visual system that images from each eye are merged (the point where depth perception occurs). This section sends output to 60% of the brain! This is a huge amount, and makes the visual system incredibly important to the decision making process.
This tutorial had a huge quantity of useful information and was really well put together! She concluded with a great summary of four things to remember:
- There are different response rates for different stimuli, how well do you want to convey magnitude information?
- Color and luminance mechanisms have different spatial sensitivities.
- Certain visual information is perceived “pre-attentively” such as color.
- How the world is perceived depends on what the user is trying to accomplish.
The IEEE VAST Challenge this year consisted of three mini challenges and one “grand challenge”. For the uninitiated, the challenge datasets are designed to reflect real-world analytical challenges. This year’s challenges involved microblog+geospatial data, cyber security data, and a corpus of plain-text news documents.
While there is no “winner”, the challenge entries are given awards based on their respective strengths. Participants are also given detailed feedback from both visualization experts and actual analysts who work with such data. This feedback is one of the most rewarding aspects of the VAST Challenge. As we all know, it’s hard to get access to analysts.
One highlight is a geo-text visualization approach from the Universität Stuttgart. ContentLens is a novel integration of tag-cloud methods and geo-visualization and interaction techniques. Perhaps if you ask nicely, they’ll give another demo.
Another interesting approach come from Penn State, who leverage their GeoViz toolkit to analyze a large (10gb+) set of cyber security data. In fact, the security data took center stage in a panel of security and/or visualization practitioners.
Some key points in the panel suggested a need for smart collaboration in large-scale security analysis. Analysts can often unnecessarily repeat work or miss threats that has already been addressed by other analysts in their organization. Maybe we need an “Amazon- Recommendations” component for security analysis tools.
Finally, workshop participants heard about and discussed the possible future VAST Challenges. Can visual analytics handle a million-node network? Can this community design tools that enable consumers to make discoveries in the vast sea of data that surrounds them? Well, that’s up to you.
Link to detailed challenge descriptions: http://hcil.cs.umd.edu/localphp/hcil/vast11/index.php/taskdesc/index .