MSState VisLab: Blogs

SCons

2008-01-29T16:30:26+00:00

SCons is a "next generation" build tool written in Python. It is a make replacement, and much more. It will create PDFs from latex, compile C, C++, JAVA, MS Visual Studio Projects, and anything else you can think of. This would be a wonderful tool for cross-platform development, or development of a very heterogeneous system.

dict.get and dict.index revisited

2007-10-30T19:43:51+00:00

I did a little more 'thorough' testing on the differences between dict.get(key) and dict[key]. I tested for both keys that do and do not exist, and I seem to have different results than what I did last time =(

It seems dict[key] is about twice as fast as dict.get(key) when the key does exist in the dict. On the other hand, dict[key] + exception handling is twice as slow as dict.get(key) when key is not in dict. Here's the extra twist: checking if the key is in dict and then getting the appropriate value is only slightly slower than simply table[key]. This is something like:

if key in dict: 
    value = dict[key] 
else: 
    value = None

or, more elegantly:

value = None if key not in dict else dict[key]

This method is fractionally slower than dict[key] when key is in the table, but it's considerably faster when key is not in the table. Also, this method is consistantly faster than dict.get(key) in both cases.

The script can be found [here]
The output for 100,000 iterations of each case can be found [here]

The output shows the name of each test case followed by the commands executed in the test. Total runtime for each follow each.

I may have done the cases a little naively, but I still think it shows some powerful differences.

Installing GLEW and GLEWpy in Python2.5 on OS X

2007-10-30T19:28:12+00:00

Installing GLEW
Download the GLEW source from [here]
Run the following command in the glew folder:

> GLEW_DEST=/usr/local sudo make install

Installing GLEWpy
Download the GLEWpy source from [here]
Replace the setup.py in the glewpy folder with the modified setup.py from [here]
Run the following command in the glewpy folder:

> sudo python setup.py install

SSH minus Login

2007-10-29T18:01:03+00:00

This is useful for 'faster' logins, or programs that use SSH and don't support a login (ex: SCPlugin SVN GUI for OSX)

On local machine, create and upload the key:

> ssh-keygen -t dsa 
** overwrite if you need to ** 
** enter empty passphrase (is this safe?) ** 
> scp ~/.ssh/id_dsa.pub username@server

> cat id_dsa.pub >> .ssh/authorized_keys 
> rm id_dsa.pub

I did this a while back, but never took notes. *sigh*

Multi-Touch Demo.

2007-10-26T00:01:46+00:00

Very impressive demo of a large scale multi-touch display wall.

PyGPU

2007-10-17T15:55:00+00:00

PyGPU

Seam Carving

2007-10-17T13:28:48+00:00

Here's an image resizing technique presented at Siggraph '07.

http://www.youtube.com/watch?v=6NcIJXTlugc

Generic Display Configuration

2007-10-03T14:23:06+00:00

On my laptop I have a fork of the keyboard/mouse input code that can be used to take an arbitrary number of computers and control them with one keyboard & mouse. This post is just a reminder to myself to add it to svn. I know there are 3rd party applications for this, but who knows, it could still be useful.

3D Software in Python

2007-10-03T12:19:22+00:00

Here's a collection of Python 3D software. I'm tempted to experiment with some of these, but there just aren't enough hours in a day.

Congratulations Ketan and Swati!

2007-10-03T12:17:33+00:00

Ketan and Swati have just had a new addition to their family. Congratulations and Best Wishes!!

Cluster Software

2007-10-03T12:14:56+00:00

This list enumerates the various (3rd party) software used on the cluster. It will be amended as I think of more.

Python
PyOpenGL
Python Imaging Library
Glew
Pyrex
GlewPy
Python Cryptography Toolkit
PyGame

I also have some installation/configuration notes in the works. I will add these after I get them organized.

Python and Indentation

2007-09-26T13:30:16+00:00

A lucid explaination of the purpose and logic behind indentation in Python.

Using PIL Images with wxPython

2007-09-17T16:17:27+00:00

def GetWXBitmap(myImage): 
    image = apply(wx.EmptyImage, myImage.size) 
    image.SetData(myImage.convert("RGB").tostring()) 
    # if the image has an alpha channel, 
    # you can set it with this line: 
    myImage = myImage.convert("RGBA") 
    image.SetAlphaData(myImage.tostring()[3::4] ) 
    return image.ConvertToBitmap()

FROM:
http://wiki.wxpython.org/WorkingWithImages#head-7aa43a4a1e066fd28640ce86066ba0617afe2a8b

Using wx.StaticBitmap (widget on the window to show the bitmap):
http://wiki.wxpython.org/wxStaticBitmap?highlight=%28Bitmap%29

cluster workflow

2007-09-14T11:18:50+00:00

This automator workflow is used on all the cluster nodes. It mounts the current source tree from Visual and the shared data & scratch directories on Mini.

HVCE Book Chapter Published

2007-08-09T15:30:16+00:00

In the new book published by Springer, Human-Centered Visualization Environments, edited by Andreas Kerren, Achim Ebert and Jörg Meyer, I co-contributed a chapter entitled "Interacting with Visualizations." My co-authors are F. Wim Fikkert (U. Twente, Netherlands), Marcos D'Ambros (U. Lugano, Switzerland), and Torsten Bierz (U. Kaiseslautern, Germany).

Code Like a Pythonista

2007-07-26T14:15:07+00:00

David Goodger, a member of the Python Board of Directors, has a good discussion on writing idiomatic Python. Worth a read.

wxpython progress

2007-06-14T17:28:31+00:00

After displaying image on wxgrid header, the next step is to embed combobox in grid cells

Spelling Corrector in 20 lines of Python code

2007-04-09T14:15:45+00:00

Why are imperfectly spelled searches "good enough" for Google? Here is a spelling corrector that does the job in only 20 lines of Python code

Python IDEs in Use

2007-03-08T16:20:40+00:00

ShowMeDo, a sort of YouTube video source for software tutorials, has aggregated screencasts demonstrating various Python integrated development environments. While I have not used many of these (guess I'm too old fashioned), they should be of use to new Pythonistas or folks like my wife who refuse to code without an IDE.

Paper: CluVis: Dual-domain Visual Exploration of Cluster/Network Metadata

2007-02-14T15:38:33+00:00

Chris Waters, Jon Howell, and I have had our work on cluster visualization accepted to ACMSE 2007. The full reference is:

Christopher Waters, Jonathan Howell, and T.J. Jankun-Kelly. "CluVis: Dual-domain Visual Exploration of Cluster/Network Metadata" In Proceedings of the 45th Annual Southeast Regional Conference (ACMSE 2007), Darina Dicheva and Paúl Pauca, eds., March 2007.

Chris will present the paper. The work grew out of a class project in my 2005 offering of Information Visualization.

glewpy

2007-01-25T11:26:49+00:00

I can't seem to get glewpy to work under python2.5 on a PPC mac.

ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/site-packages/glew/glew.so, 2): Symbol not found: _glewInit
Referenced from: /Library/Frameworks/Python.framework/Versions/2.5/lib/
python2.5/site-packages/glew/glew.so
Expected in: dynamic lookup

Any idea why this symbol is not found in glew.so ?

MMS Papers

2006-11-29T13:25:15+00:00

The first paper "The Modular Modeling System (MMS): A Toolbox for Enviormental-Resource Management" describes the system that the USGS created to integrate it various models. The system is a sort of development environment where a complex model is made by linking the input and output of many smaller models.

The second paper "Streamflow Forecasting Using the Modular Modeling System and an Object-User Interface" describes the creation of a watershed model using the MMS system.

Nasa probably want a system similar to the MMS designed and implemented for their various models. Which would be software development and not research at all.

Advanced Techniques for Watershed Visualization

2006-11-29T13:06:17+00:00

The paper describes a method of a determining watersheds by coloring a DEM using a map of divergence of flow directions. The rendering process is not complicated and the only unusually thing being used to determine coloring. The image resulting form this is then manually segmented into basins. task that the coloring makes fairly trivial. The only prospective research is developing an algorithm that automates the last part and comparing it to existing basin delineation programs. This is not a Visualization problem.

Paper Summaries

2006-11-29T13:03:58+00:00

Don't Do Game Progamming [As a Degree]

2006-11-17T19:09:07+00:00

There has been some debate on in CS circles on whether game degrees should be offered in difference to straight CS/SE degrees. As a visualization/graphics guy, I'm often asked this directly. My gut feeling is that such a degree is of little use in the real world. Non-game companies want a "real" degree while game companies do not care. It appears my feeling is right. This comment is from John Carmack, one of the big two behind Doom and many other important game developments.

wxPython Practice and Documentation Woes

2006-11-09T15:10:02+00:00

If you're familiar with wxPython, you may also be familiar with the many ways you can do/import the same exact thing... or are they the same?

When porting ~~wxWindows~~ wxWidgets to Python, there ended up being class name conversions like "wxPanel" to "wx.Panel". At the same time (!!), you can use "wxPython.wxPanel". This wouldn't be so bad if the wxPython Wiki stuck with -one- of these. There is a Style Guide on the wiki, but that doesn't seem to be followed very well. =(

The wxOGL page is very guilty of inconsistencies.

An Atmospheric Visual Analysis and Exploration System

2006-11-08T03:13:23+00:00

Y. Song, J. Ye, N. Svakhine, S. Lasher-Trapp, M. Baldwin, and D. Ebert, “An Atmospheric Visual Analysis and Exploration System,” IEEE Transactions on Visualization and Computer Graphics, vol. 12, no. 5, Sep. 2006, pp. 1157–1164.

Click here for reading notes.

This paper is from the recent Vis06 conference proceedings. The paper discusses visualization of radar data for assessing the performance of weather forecasting models. Also, they discuss ways to visualize the affect of dry air influx.

Outlier-Preserving Focus+Context Visualization in Parallel Coordinates

2006-11-08T03:09:01+00:00

M. Novotny and H. Hauser, “Outlier-Preserving Focus+Context Visualization in Parallel Coordinates,” IEEE Transactions on Visualization and Computer Graphics, vol. 12, no. 5, Sep. 2006, pp. 893–900.

Click here for reading notes.

From the recent Vis06 conference proceedings. The parallel coordinates techniques will be directly applicable to the weather visualization I am coding for my Information Visualization course project. I am particularly interested in the binning method described in the paper because it might give me better rendering performance.

Winner: Best Panel, IEEE Visualization 2006

2006-11-03T20:23:41+00:00

The panel I moderated at IEEE Visualization 2006 won Best Panel! The details of the panel are as follows:

Moderator: T.J. Jankun-Kelly. Panelists: Robert Kosara, Gordon Kindlmann, Chris North, Colin Ware, E. Wes Bethel, "Is There Science in Visualization? "

Parallel Coordinates Papers

2006-10-19T21:08:54+00:00

I do not have time to summarize these papers but I wanted to post them anyway (it may be a while before things settle down). All are related to parallel coordinates. Some are new some are old (classics).

[1] E. Fanea, S. Carpendale, and T. Isenberg, “An Interactive 3D Integration of Parallel Coordinates and Star Glyphs,” Proceedings of the IEEE Symposium on Information Visualization 2005, Minneapolis, Minnesota, Oct. 2005, IEEE Computer Society, pp. 149–156.

[2] M. Graham and J. Kennedy, “Using Curves to Enhance Parallel Coordinate Visualisations,” Proceedings of the International Conference on Information Visualization,
London, England, Jul. 2003, IEEE Computer Society, pp. 10–16.

[3] L. O. Hall and M. R. Berthold, “Fuzzy Parallel Coordinates,” Proceedings of the International Conference of the North American Fuzzy Information Processing Society, Atlanta, Georgia, Jul. 2000, IEEE Computer Society, pp. 74–78.

[4] H. Hauser, F. Ledermann, and H. Doleisch, “Angular
Brushing of Extended Parallel Coordinates,” Proceedings of IEEE Symposium on Information Visualization 2002, Boston, Massachusetts, Oct. 2002, IEEE Computer Society, pp. 127–130.

[5] A. Inselberg and B. Dimsdale, “Parallel Coordinates: A Tool for Visualizing Multidimensional Geometry,” Proceedings of IEEE Visualization 1990, San Francisco, California,
Oct. 1990, IEEE Computer Society, pp. 361–378.

[6] M. Jern and J. Franz´en, ““GeoAnalytics” – Exploring Spatio-temporal and Multivariate Data,” Proceedings of the Information Visualization 2006, London, United Kingdom, Jul. 2006, IEEE Computer Society, pp. 25–31.

[7] H. Siirtola, “Direct Manipulation of Parallel Coordinates,” Proceedings of the International Conference on Information Visualisation, London, England, Jul. 2000, IEEE
Computer Society, pp. 373–378.

[8] C. Tominski, J. Abello, and H. Schumann, “Axes-based Visualizations with Radial Layouts,” Proceedings of the ACM Symposium on Applied Computing, Nicosia, Cyprus, Mar. 2004, ACM, pp. 1242–1247.

Integration

2006-10-19T14:21:31+00:00

I'm at a stage where I need to merge some of the code from the various branches. There are now so many sub-projects in this work that it will become unmanageable unless care is taken to organize everything properly.
The inter-application protocol is already in one file and is shared between the modules. However, configIO, utilmath, and code other code dealing with transfer function editing and encoding need to be unified. One new piece that I will likely write today is a class that abstracts transfer function information. This class will also provide a toString-like function for use in network transmission.

Friday I will try to launch the entire system for the first time. I will begin by testing the following

-Communication from each application to the head node.
-Communication from the head node to each app.
-Using the app-switcher to do an initial application launch.
-Using the app-switcher to kill one application and switch to another.

PyOpenGL 3.0 (ctypes) alpha available

2006-10-16T11:09:24+00:00

Good news for us: An alpha version of PyOpenGL 3.0 (the ctypes version) is now available for playing with. Now we can get our Intel Macs back in production mode hopefully.

Update: We are happy to report that PyOpenGL 3 is working just fine on our Mactels.

Javascript Canvas

2006-10-13T09:02:06+00:00

The javascript canvas is a 2D display widget avaliable on Firefox, Safari, and Opera. The is are plugins that make the widget avaliable for IE. Placing a canvas in a web page is almost identical to placing a picture the element requires 3 attributes: height, width, and id. Placing a canvas results in a blank rectangle of the specified hieght and width. All drawing on the canvas is done with a javascript calls.

The canvas 2D api is quite advanced and has support for the following operations.

Canvas State Methods

* restore - restore canvas to last saved state
* rotate - rotate the coordinate space
* save - save the canvas state
* scale - scale the cordiante space
* translate - translate the cordinate space

Working With Paths

* arc
* arcTo
* bezierCurveTo
* beginPath
* clip
* closePath
* lineTo
* moveTo
* quadraticCurveTo
* rect

Stroking a Path

* stroke
* strokeRect

Filling an Area

* clearRect
* fill
* fillRect

Creating Gradient and Pattern Styles

* addColorStop
* createLinearGradient
* createPattern
* createRadialGradient

Drawing an Image

* drawImage
* drawImageFromRect

More functional programming in Python

2006-10-12T13:54:45+00:00

A few good links on functional programming in Python. It can be very useful sometimes, so I recommend the reading.:

Functional Programming with Python
Even More Functional Programming in Python
Xoltar Functional Programming Toolkit (some of this is available in the functools standard library module)

Via JotSite.

Slices, Launchers, etc..

2006-10-11T14:56:46+00:00

I've gotten the slice information into the fragment programs. Here are two examples of red planes which correspond to the sagital slice on the right. (And yes, I need to put a red rectangle around the 2D slice) These 2 images show the red blade with high and low opacities. The low opacity slice lets you see a bit of the cross section in the volume. I think I will add a "slicerr" opacity tool to the interface for controlling this.

Should this be a wireframe instead of a solid plane? Hmmm. I'll put up screenshots of one with a wireframe fiducial for comparison.

Also, the launcher is more or less working now. I waffled some on how much control the launcher app should have over the other programs. Should the launcher spawn and kill the other apps? Or should each program be responsible for terminating itself and launching the next application? Anyway, I think I have a handle on it now.

Angular Brushing of Extended Parallel Coordinates

2006-10-05T18:39:06+00:00

H. Hauser, F. Ledermann, and H. Doleisch, “Angular Brushing of Extended Parallel Coordinates,” Proceedings of IEEE Symposium on Information Visualization 2002, Boston, Massachusetts, Oct. 2002, IEEE Computer Society, pp. 127–130.

Click here for reading notes.

I plan to explore the extended parallel coordinates techniques in this paper to the NOAA best-track dataset soon.

NSF Awards VisLab Researchers $300,000 for Empirical Security Visualization Work

2006-09-25T16:59:24+00:00

Dr. T.J. Jankun-Kelly, Assistant Professor of Computer Science and Engineering, has learned that the project "CT-ISG: Empirically-based Visualization for Computer Security and Forensics" will be funded for 3 years by the National Science Foundation's CyberTrust program. The funding will begin on October 1, 2006. Dr. Jankun-Kelly will serve as the principal investigator (PI) for this project. The co-PIs are Dr. Jeff Carver, Assistant Professor; Dr. Ed Swan, Associate Professor; and Dr. Dave Dampier, Associate Professor.

What is Pythonic?

2006-09-24T15:56:04+00:00

This good essay by Martijn Faassen (a Zope hacker) expands on what "Pythonic" means anyway. Like the "Python is not Java" post earlier, the point of being Python is to use the language to your advantage, not to program Python as it were Java/C/C++/C#/Whatever.

NOAA National Digital Forecast Database (NDFD)

2006-09-21T17:29:30+00:00

http://www.weather.gov/ndfd/technical.htm

The NDFD is a gridded database of weather forecast information for the U.S. The data can be downloaded from the website for specific regions or nationally. This repository is a very promising source of information for my InfoVis class and/or research topic.

Have you ever noticed that most databases that are created by a government agency have the word digital embedded in the title?

Exposé-Like Application Switcher

2006-09-21T15:49:27+00:00

So I'm working on a high-level application switcher. This will allow the user to switch between applications on each panel. I'm using PyGame to dim the screen and display a graphic conaining the available options. I'm going to use Photoshop on one of the lab computers to crate a visually appealing graphic then I'll hook up the mouse events for it. Screenshot forthcoming.

Visual Color Picker Application

2006-09-20T18:52:17+00:00

http://www.linxexplorer.com/colorpicker.html

The Visual Color Picker is a great little freeware tool that lets you pick pixels (or patches of pixels) from your desktop and it gives the RGB (or HSV, CYMK) values for a location. It also has some nice capabilities to manipulate the color once you select a pixel. I recently used this tool to determine the color scale for the NWS NEXRAD RADAR website.

NWS Regional Weather Observations Source

2006-09-19T21:38:41+00:00

http://www.srh.noaa.gov/data/obhistory/KGTR.html

This website is a multivariate data source for a visualization of temporal weather observations. The page lists a 2-day history of weather observations (pressure, dewpoint, temperature, etc.) for Columbus AFB.

Invited Talk: A Model and Framework for Visualization Exploration

2006-09-18T13:40:21+00:00

Dr. Jankun-Kelly will be giving an invited talk at the Scientific Computing and Imaging Insitute, University of Utah on September 29th. The title of the talk is "A Model and Framework for Visualization Exploration":

Visualization is the process of "making the invisible visible"---the use of computer graphics to depict digitized information. The goal of visualization is insight. However, most past research in visualization, specifically scientific visualization, has been driven by the desire to generate visualizations faster and on a larger scale. In this talk, I will instead focus on the underlying process of visualization exploration itself. I will discuss this process' salient aspects and the fundamental operation a user performs during visualization exploration. This fundamental operation forms the basis of a formal model that encapsulates the visualization process. I will discuss how this form model facilitates visualization collaboration, analysis, and the science of visualization. These applications are enabled via a software framework that implements the model.

Obligatory Welcoming Post

2006-09-17T16:50:31+00:00

Wherein the reader is introduced to the purpose of this blog and finds enlightenment (or at least contributes to entropy).

Purpose

Research thrives in the space of open communication. Education is more effective when new ideas can be integrated into the curriculum. In both case, the key concept is the dialog. This blog reflects my desire to initiate such dialog to better serve the greater research community. In this space, I will discuss ongoing visualization research here in the VisLab, issues relevant to visualization education, and miscellaneous topics of interest to me (OS X, Python, etc.).

As a director of graduate students, it is my responsibility to guide them effectively. Part of this process involves demonstrating what I want from them so they can be successful. Thus, this blog is also an example of how I would like them to use their blogs.

Writing This Blog

Tim Bray has some excellent thoughts on why open discourse is a good idea. He also discusses Sun's blogging policy he helped develop. These thoughts reflect my beliefs on how science and education can strive to be as transparent as possible. Here are some axioms that I will try to maintain for this blog, and I expect my students and others using this site to follow similar rules.

Use the Blog as a Research Notebook

What I seek to achieve is to partly use this blog as part of my ongoing scholarly pursuits in visualization and related fields. In my training as a physicist, I was required to maintain a lab notebook. The key qualities of a lab notebook are:

It Records Goals What is the purpose of the experiment/code that you are working on? What is the hypothesis you are testing? What are your trying to achieve. A lab notebook keeps track of these questions so you keep the goal in mind during your work.
It Records Progress A lab notebook is a legal diary of one's progress during an experiment. Things to record are data collected, papers read (and your reflections on that reading), discussions had, analysis of preliminary results, etc. These entries are keep in chronological order, and signed and dated. The signature and date confirm that you worked on this data and that you stand by these results.
It Records Results Eventually, the goal is achieved (or not), and the end result must be published for scholarly work to continue. While the main venue of such publication are generally conferences and journals, there are always details that cannot be included in papers. In addition, most results are a living thing—they evolve over time. The lab notebook can keep track of these updates.

Clearly, there are strong parallel's between a lab notebook and a blog. While it may not be wise to record every single piece of data collected, summaries of that data is a worthwhile item of discussion and will be included here. For a research blog, papers read can be easily recorded with their BibTeX entry and URL recorded for later use. This record helps others in the lab who may wish to read the paper later, and encourages discussion on the paper.

For all this to work, it is paramount that I update the blog often. Human memory is a finite resource that should not be squandered on cataloging current research processes. This blog (like all good research journals) will act as memory. In addition, others cannot comment and build upon that which is not published.

Don't Say What You Can't Say

Some common sense must be kept in mind as I write this blog. Most research here will be ongoing. Not all preliminary work can be discussed, especially when it is in the rough stages. There is a tension between open research and the need to prevent "poaching" of results. I will have to trust my (and my student's) better better judgement here.

In addition, the network that this blog runs on is provided by the University. Thus, this blog is not an appropriate forum for me to "bad-mouth" things; bad-mouthing is generally a poor use of electrons anyway. Objective criticism is fine (and encouraged), but saying something "sucks" is not objective criticism. However, I will strive to keep such criticism on-topic to the blog's topics; potential rants about the administration will be made elsewhere. ;)

Help Each Other Out

The strength of the VisLab research group is built upon the strength of its members. Thus, it is imperative that my students and I join in the discussion of the work of our fellow lab members. We should endeavor to join in discussion on other blogs/sites that discuss matters related to our work. We should encourage others in our areas to read and comment on our blogs. As I stated previously, constant discourse is vital to the health of a field.

Write Well

I am a professor, which by any definition means I should write well. The writing in my blog should reflect that. I will strive for correct spelling and grammar (though I guarantee a few slips here and there). I will proofread. Links to appropriate references will be given in a scholarly manner (i.e., name and title of references); and the links should be to fairly permanent, informative, or trustworthy sources. Links are very important; it makes the whole hyperlink discussion work.

Keep Perspective

Communication is only part of my job as a researcher and educator. This blog will not eat up all of my time. It should not eat up all the time of my students as well. Tools for aggregating feeds from the VisLab blogs (for efficient browsing) will be utilized (I use NetNewsWire); tools for efficient editing will also be used (I use ecto). I will blog, but not every hour.

Pushing the Boundaries

This site of blogs is in its own way an experiment in facilitating visualization education and research. This idea (in general) is not new, but is worthwhile to explore in this context. We'll keep you posted on how it works out.

Website changes

2006-09-16T23:52:34+00:00

I've updated a few things on the VisLab website; chiefly, a new admin person has been filling out detail on the main site while I have installed Planet in order to aggregate the various VisLab blogs. Now all the VisLab blogs can be accessed from one URL.

A Rule-based Tool for Assisting Colormap Selection

2006-09-15T02:36:03+00:00

L. D. Bergman, B. E. Rogowitz, and L. A. Treinish, “A Rule-based Tool for Assisting Colormap Selection,” Proceedings of 6th IEEE Visualization 1995 Conference. IEEE Computer Society, 1995, pp. 118–125, http://www.research.ibm.com/dx/proceedings/pravda/ (current 14 Sep. 2006).

Click here for reading notes.

Face-based Luminance Matching for Perceptual Colormap Generation

2006-09-15T02:32:31+00:00

1] G. Kindlmann, E. Reinhard, and S. Creem, “Face-based Luminance Matching for Perceptual Colormap Generation,” Proceedings of Visualization 2002. IEEE Computer Society, 2002,
http://www.cs.utah.edu/~gk/papers/vis02/ (current 14 Sep. 2006).

Click here for reading notes.

Color Use Guidelines for Data Representation

2006-09-15T02:31:00+00:00

C. A. Brewer, “Color Use Guidelines for Data Representation,” Proceedings of the Section on Statistical Graphics, Alexandria, Virginia, 1999, American Statistical Association, pp. 55–60, http://www.personal.psu.edu/faculty/c/a/cab38/ColorSch/ASApaper.html (current 14 Sep. 2006).

Click here for reading notes.

How NOT to Lie with Visualization

2006-09-15T02:29:42+00:00

B. E. Rogowitz and L. A. Treinish, “How NOT to Lie with Visualization,” Computers in Physics, vol. 10, no. 6, 1996, pp. 268–273, http://www.research.ibm.com/dx/proceedings/pravda/truevis.htm (current 14 Sep. 2006).

Click here for reading notes.

Perceptual Principles for Effective Visualizations

2006-09-15T02:22:00+00:00

P. Rheingans and C. Landreth, “Perceptual Principles for Effective Visualizations,” Perceptual Issues in Visualizations, G. Grinstein and H. Levkowitz, eds., Springer-Verlag, 1995, pp. 59–74, http://www.cs.umbc.edu/rheingan/pubs/perception.ps.Z (current 14 Sep. 2006).

Click here for reading notes.

Review: Real-Time Lens Distortion Correction

2006-09-14T13:52:57+00:00

A brief literature review follows. This is more of a topic reference for myself, than an in-depth discussion of the paper itself.

REAL-TIME LENS DISTORTION CORRECTION: 3D VIDEO GRAPHICS CARDS ARE GOOD FOR MORE THAN GAMES
Michael R. Bax
----------------------------------------------------
Bax discusses a method of using a GPU based approach for rapidly compensating for lens distortion using polar transformations. Bax's method differs from other methods I have seen in that it does not use a Cartesian based grid. Instead, this method uses a polar based system of concentric bands of triangles. These triangles represent the component parts of a surface over which the distorted image is texture mapped. The warped surface produced a counter-distorting effect which effectively straightens the distortion in the image. Bax's research showed that this polar based method is actually 50% more effective in error reduction than a standard grid based method. It was also found that this procedure could take place in real-time, providing a frame rate of at least 30 fps.

Side Note: In a recent experiment we did here in the AR lab, we used a grid based approach to resolving lens distortion in a Sony Glasstron binocular, non-stereo HMD. However, the polar based method described in Bax's paper would not have been sufficient in our case due to additional, non-uniform distortion introduced by a set of plastic anaglyph filters placed on the HMD's oculi to enable stereo vision. Instead, we used the Cartesian grid based method. This method produced sufficient error reduction and allowed more fine grained (though very time consuming) distortion correction.

Review: Recent Advances in Augmented Reality

2006-09-13T13:08:46+00:00

A brief literature review follows. This is more of a topic reference for myself, than an in-depth discussion of the paper itself.

RECENT ADVANCES IN AUGMENTED REALITY
R. Azuma, Y. Baillot, R. Behringer, S. Feiner, S. Julier, B. MacIntyre
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Azuma et.al. present an interesting survey of the state of AR technology, its recent advances, and its limitations in this paper from 2001. They provide a useful overview of topics including tracking, registration, usability, and interaction. An excellent break down of the different levels of virtual reality and augmented reality is presented as well. Various AR methods are also mentioned. These range from head worn displays to retro-reflective projection based systems. Current and potential applications for AR are also given. Some examples include military planning, simulation, navigation, factory work, construction, medical procedures, advertising, and entertainment. A brief discussion of environmental sensing is also included. This is an interesting topic, especially for unprepared environments, such as the outdoors. Indoor tracking in a prepared environment is easier but still a non-trivial task. Some techniques discussed exploit characteristics of particular locations, such as pipes and conduits running along walls and ceilings in a factory. The issue of “social acceptance” is also discussed as being a little addressed but highly influential factor in determining the future of AR among the general population.

InfoVis Evaluation Papers

2006-09-13T10:17:43+00:00

The folks from Beliv06 have put together a very useful resource: A compilation of evaluation studies in Information Visualization. These are worthy to take a look at. Unfortunately, the proceedings have not gone online yet.

A Cool Example of Qt and OpenGL

2006-09-07T04:02:46+00:00

http://wwwx.cs.unc.edu/~quirk/class/Comp236/final/index.php

Qt 4.1 Tutorial and Documentation

2006-09-06T19:56:52+00:00

I am changing my visualization software from Java to C++ to increase performance. Using C++ with Qt and OpenGL for UI and graphics seems like the best option now and I already know it (somewhat). For now I will work a few examples out in the tutorial. I may switch from C++ to Python in the future (PyQt) but for now I will stick with C++.

Qt 4.1 Documentation Website

A Taxonomy of Visualization Techniques Using the Data State Reference Model

2006-09-06T15:31:06+00:00

Chi, E. H. 2000. A Taxonomy of Visualization Techniques Using the Data State Reference Model. In Proceedings of the IEEE Symposium on information Vizualization 2000 (October 09 - 10, 2000). INFOVIS. IEEE Computer Society, Washington, DC, 69. http://portal.acm.org/citation.cfm?id=857691

A unified taxonomic framework for information visualization

2006-09-06T15:30:36+00:00

Pfitzner, D., Hobbs, V., and Powers, D. 2003. A unified taxonomic framework for information visualization. In Proceedings of the Asia-Pacific Symposium on information Visualisation - Volume 24 (Adelaide, Australia). T. Pattison and B. Thomas, Eds. ACM International Conference Proceeding Series, vol. 142. Australian Computer Society, Darlinghurst, Australia, 57-66. http://portal.acm.org/citation.cfm?id=857087

Taxonomy: Animals or Visualizations?

2006-09-06T15:25:24+00:00

I've been working on developing a sort of 'taxonomy' to classify Information Visualizations. The taxonomy is a combination of visualization factors from Pfizner '03 [url] and Chi '00 [url]. The hope is to find similar characteristics between the different information visualizations.

Volume Server Invocation

2006-09-06T15:05:16+00:00

#Here's some instruction for how to submit rendering tasks. First,
import Image, zlib
from pipeComm import RaycasterComm
import configIO

#This command mounts the data drives on the cluster.
configIO.mountDataDrives()

#Create a renderer.
rayComm = RaycasterComm( filename, texture_size )

#This will return a rendering with the initial viewpoint, linear color and #opacity maps, etc.
img = rayComm.GetNextImage()

#Now, rotate the volume without returning an image.
rayComm.Rotate(0, 90, 0, False )

#Now, rotate the volume and return an image.
image = rayComm.Rotate(0,0,45, True)

#Save the image to a file.
image.save('filename.png')

Python is not Java

2006-09-01T08:08:22+00:00

Joe Gregorio, who does a column on using Python for REST applications wrote a brief discussion of how Python and Java differ. He makes some good points, but confuses first class functions (C has non-member functions and they are not exactly first class, that requires passing semantics and being able to create them on the fly, both of which Python has), closures (Python almost has true closures, but not quite), and continuations (python has generators and soon co-routines which do some of the continuation work, but not all).

MSState VisLab: Blogs

SCons

dict.get and dict.__index__ revisited

Installing GLEW and GLEWpy in Python2.5 on OS X

SSH minus Login

Multi-Touch Demo.

PyGPU

Seam Carving

Generic Display Configuration

3D Software in Python

Congratulations Ketan and Swati!

Cluster Software

Python and Indentation

Using PIL Images with wxPython

cluster workflow

HVCE Book Chapter Published

Code Like a Pythonista

wxpython progress

Spelling Corrector in 20 lines of Python code

Python IDEs in Use

Paper: CluVis: Dual-domain Visual Exploration of Cluster/Network Metadata

glewpy

MMS Papers

Advanced Techniques for Watershed Visualization

Paper Summaries

Don't Do Game Progamming [As a Degree]

wxPython Practice and Documentation Woes

An Atmospheric Visual Analysis and Exploration System

Outlier-Preserving Focus+Context Visualization in Parallel Coordinates

Winner: Best Panel, IEEE Visualization 2006

Parallel Coordinates Papers

Integration

PyOpenGL 3.0 (ctypes) alpha available

Javascript Canvas

More functional programming in Python

Slices, Launchers, etc..

Angular Brushing of Extended Parallel Coordinates

NSF Awards VisLab Researchers $300,000 for Empirical Security Visualization Work

What is Pythonic?

NOAA National Digital Forecast Database (NDFD)

Exposé-Like Application Switcher

Visual Color Picker Application

NWS Regional Weather Observations Source

Invited Talk: A Model and Framework for Visualization Exploration

Obligatory Welcoming Post

Purpose

Writing This Blog

Use the Blog as a Research Notebook

Don't Say What You Can't Say

Help Each Other Out

Write Well

Keep Perspective

Pushing the Boundaries

Website changes

A Rule-based Tool for Assisting Colormap Selection

Face-based Luminance Matching for Perceptual Colormap Generation

Color Use Guidelines for Data Representation

How NOT to Lie with Visualization

Perceptual Principles for Effective Visualizations

Review: Real-Time Lens Distortion Correction

Review: Recent Advances in Augmented Reality

InfoVis Evaluation Papers

A Cool Example of Qt and OpenGL

Qt 4.1 Tutorial and Documentation

A Taxonomy of Visualization Techniques Using the Data State Reference Model

A unified taxonomic framework for information visualization

Taxonomy: Animals or Visualizations?

Volume Server Invocation

Python is not Java

dict.get and dict.index revisited