Wednesday, April 30, 2008

Writing CAS/HFP on XML file

Since I will now test the CAS/HFP algorithm with larger collections, I needed to devise a way to store the segmentation in order to be able to re-use it without having to process it again. Thus, I have implemented a feature that allows writing to (and reading from) a XML file the segmented collection. Moreover, the computed signatures for segments and corresponding similarities are also saved. Below is an excerpt of a XML file describing a collection decomposition.

Excerpt of XML decomposition file.

Thursday, April 24, 2008

CAS/HFP versus HFP

During the last weeks I've been implementing the context-aware decomposition based on hierarchical fitting primitives (CAS/HFP) algorithm. Now that I finally have a working prototype, I was able to compare the result produced by CAS/HFP with the ones produced by applying only the hierarchical fiting primitives (HFP) segmentation. To that end I use a very small collection extracted from the PRECISE Engineering Shape Benchmark. Below I show the segmentation trees produced by the two algorithms for the same shape.

Decomposition tree produced by HFP

Decomposition tree produced by CAS/HFP

Wednesday, April 09, 2008

Me and C++, a love/hate relationship

It is not something new. It has always been like that. These last two days were just another example of this. Yesterday, I was cursing C++. I have been fighting to solve some major memory leaks on my code... and it was hard... I hate C++!!! Today I finally finished solving that problem and moved forward. Moved to a completely different issue. In this I apply the flexibility and power of C++ to implement an algorithm that can be compiled using only standard libraries or using wxWidgets (and taking advantage of it). The most beautiful point is that I did it in just a couple of hours and the only thing I now have to do, if I want to switch, is change a single line of code. Indeed, I love C++!!!

Monday, April 07, 2008

First approach to context-aware segmentation

In a first approach to context-aware segmentation (CAS), I have implemented a prototype that uses spherical harmonics descriptor and cord-and-angle histogram to estimate similarities between segments. This prototype decomposes all models in a given collection according to all others. Bellow is an example of a model extracted from the PRECISE Engineering Shape Benchmark and decomposed along with others from this benchmark using the CAS approach.

View of 3D model decomposed using CAS

Wednesday, April 02, 2008

I have took a few days off to spent with my family here in Genoa. Now they returned home and I'm back to work. Nevertheless, there were a short but very good vacations, where we had lots of fun. At least my son enjoyed everything. Specially the children's race track at Corso Italia.

My son riding on the children's race track