Reviews

Torsten Rohlfing

Wednesday 26 September 2007

Summary:
This submission provides an implementation of a diffeomorphic nonrigid demons registration algorithm. It comes with a stand-alone command line tool that provides many useful options and is fit for production use.

Evidence:
The authors provide test images.

Open Science:
Source code and test data are provided.

Reproducibility:
I have not tested the tool with the data provided by the authors. I have, however, run extensive tests on my own data in a longitudinal deformation-based morphometry study. I find the core algorithm to be very efficient and about as accurate as the original demons algorithm. I was also able to confirm that the produced transformations are essentially diffeomorphic. There occasionally  appear to be small fractions of pixels with negative Jacobians, but this seems mostly connected to almost-folding input deformation fields that I sometimes provide to the algorithm.

Use of Open Source Software:
Uses ITK.

Open Source Contributions:
Source code is provided. Compiles successfully out of the box using current CVS version of ITK.

Code Quality:
The code quality is excellent. The code appears to conform with ITK coding style and is virtually fully documented. The bundled command line tool provides options for different update rules, multi-resolution registration, initial deformation fields, and intensity histogram normalization.

Applicability to other problems:
n/a

Suggestions for future work:
n/a

Requests for additional information from authors:
n/a

Additional Comments:
I would strongly advocate adding this contribution to ITK as soon as possible. The nonrigid registrations in the toolkit are a little outdated right now and could really use some newer algorithms. In particular diffeomorphic registration has become a hot topic recently, and it would be great to have a diffeomorphic registration algorithm available in ITK, in particular one that is as efficient as this one. I would also advocate including the command line tool that comes with the software in the ITK source tree.

 

Kevin Cleary

Tuesday 11 September 2007

Summary:
In this paper a modified version of Thirion’s Demons Registration algorithm is presented.As authors mention this is a companion paper to the paper “Non-parametric diffeomorphic image registration with the demons algorithm” published in MICCAI 2007 with the purpose of sharing the source code with the community. Instead of presenting in detail the algorithm they insist more on the ITK implementation issues.To understand the method and to see the evaluation of the algorithm the reader has to read also the initial paper.

Hypothesis:
Lie group structure on diffeomorphic transformations  can be used in combination with some optimization tools on Lie groups to derive our diffeomorphic image registration algorithm.

Evidence:
They provide the source code with only one 128x128 two examples 2D example.I couldn’t execute the code on Visual Studio 8.0 because the file getopt.h was missing.

Open Science:
They provide the full source code based on ITK and they provide one data set.The actual paper contain no images only general description of the algorithm and details on ITK implementation.The original MICCAI paper contains images and results based on different data that is not available with this source code.

Reproducibility:
Did not run on Microsoft Visual Studio 8.0

Use of Open Source Software:
Their implementation is based on ITK.Actualy they are also one of the important contributors of the Demons registration in ITK.This algorithm is only an extension to the current ITK framework
Open Source Contributions:
The code is well written and it contains reasonable comments inside the code
Code Quality:
Seems it doesn’t compile on Visual Studio 8.0 because of an utility file: getopt.h

The files are following ITK coding style and it is easy to read

Applicability to other problems:

Suggestions for future work:

Requests for additional information from authors:

Additional Comments:

This review was written by Teo Popa in our laboratory and posted by Kevin Cleary.