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| ID | Project | Category | View Status | Date Submitted | Last Update | ||||
| 0005292 | ITK | public | 2007-07-04 11:20 | 2007-07-05 13:02 | |||||
| Reporter | Ivan Macia | ||||||||
| Assigned To | Luis Ibanez | ||||||||
| Priority | high | Severity | major | Reproducibility | always | ||||
| Status | closed | Resolution | fixed | ||||||
| Platform | OS | OS Version | |||||||
| Product Version | |||||||||
| Target Version | Fixed in Version | ||||||||
| Summary | 0005292: Wrong computation of gaussian derivatives in HessianRecursiveGaussianImageFilter | ||||||||
| Description | As pointed out by Won-Ki Jeong http://public.kitware.com/pipermail/insight-users/2007-July/022770.html [^] when computing second order derivatives in the same direction twice, for example (G*I)xx, the filter applies 1D recursive Gaussian order-1 derivative filter twice along x and applies 1D recursive Gaussian filter along y, that means along x the Gaussian is applied twice but there is no Gaussian for z direction. The same applies for (G*I)yy and (G*I)zz in 3D. The number of smoothing filter is fixed in the static member NumberOfSmoothingFilters = ImageDimension-2, so in the 3D case there is only a single smoothing filter where there should by two for computing (G*I)xx I made a small test with a 3D MRI image, applied HessianRecursiveGaussian filter with sigma = 5.0 and extracted the six components of the hessian tensor. The attached image shows an slice of the original image and the sixth component (G*I)zz of the hessian matrix of the same slice. It seems like there is smoothing in x but no smoothing in y (see the narrow horizontal lines). | ||||||||
| Tags | No tags attached. | ||||||||
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| Attached Files |  MRI_HessianGzz_Slice44.zip [^] (29,570 bytes) 1969-12-31 19:00 itkHessianRecursiveGaussianImageFilter.txx [^] (7,244 bytes) 1969-12-31 19:00 itkHessianRecursiveGaussianImageFilter.h [^] (6,441 bytes) 1969-12-31 19:00 MRI_HessianGzz_Slice44_Fixed.jpg [^] (8,719 bytes) 1969-12-31 19:00
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(0007991) Ivan Macia (developer) 2007-07-04 12:41 |
I uploaded an updated version that fixes the problem |
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(0007992) Luis Ibanez (manager) 2007-07-05 11:48 |
This bug is a duplicate report from 4934. A fix has been committed to the CVS repository. Ivan, could you please report what version of ITK are you using ? |
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(0007996) Luis Ibanez (manager) 2007-07-05 13:02 |
The issue has been fixed on bug 0004934. http://public.kitware.com/pipermail/insight-users/2007-July/022794.html [^] |
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