Steve on Image Processing

February 1st, 2010

Updates on old business: upslope area and unit testing

A couple of papers have been published recently that are related to some of my old blog topics.

Almost exactly a year ago I posted an xUnit-based unit test harness for MATLAB to the MATLAB Central File Exchange, and I blogged about it here.

Later in the year I wrote an article about it for Computing in Science and Engineering, a joint publication of the IEEE Computer Society and the American Institute of Physics. The article, "Automated Software Testing for MATLAB," appears in the November 2009 issue.

In 2007 I did a series of blog post on developing MATLAB algorithms for a topological measurement called upslope area, a measurement related to digital elevation models (DEMs). The upslope area of a point (pixel) is the total area on the terrain above that point that drains through it. I formulated the computation of upslope area as a sparse linear system, which let me put the MATLAB backslash operator to good use, and I put my upslope area functions on the File Exchange.

At about the same time, File Exchange contributor Wolfgang Schwanghart was developing a similar approach. His paper (with Nikolaus Kuhn), "TopoToolbox: A set of Matlab functions for topographic analysis," is in the January 2010 issue of Environmental Modelling & Software. TopoToolbox is available here.

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MathWorks
Steve Eddins is a software development manager in the MATLAB and image processing areas at MathWorks. Steve coauthored Digital Image Processing Using MATLAB. He writes here about image processing concepts, algorithm implementations, and MATLAB.

These postings are the author's and don't necessarily represent the opinions of The MathWorks.