[vtkusers] CT Gantry Tilt correction

[satwik k]

Thanx David. It helped me a lot.

Now it is taking less than 2 sec.

Regards,
Satwik K

On Thu, Nov 30, 2017 at 10:38 PM, David Gobbi <david.gobbi at gmail.com> wrote:

> The time will be proportional to the number of slices in the volume.
>
> I've pushed a change to github so that you can call the following method
> to speed things up:
>
>   rectify->SetInterpolationModeToLinear();
>
> Linear interpolation will be at least 10 times faster than sinc
> interpolation.
> Just grab the latest master branch and this method will be available.
>
> When I have some time, I'll dig into the sinc interpolation code to speed
> it up.
> Right now it's just using vtkImageReslice and a 3D sinc kernel, but CT
> rectification really only needs a one-dimensional kernel.
>
>  - David
>
>
>
> On Thu, Nov 30, 2017 at 8:24 AM, satwik k <satwik.k8 at gmail.com> wrote:
>
>> Last time when I used this API.. By mistake added in loop.. so it was
>> taking more time... But now I moved it some where else method.. Now it is
>> taking around 10sec... My doubt is, for 144 images.. it is taking this much
>> extra time.. wht if have 1000images..?
>>
>> will it take same time or more?
>>
>>
>> Regards,
>> Satwik k
>>
>> On Nov 30, 2017 19:31, "David Gobbi" <david.gobbi at gmail.com> wrote:
>>
>>> Hi Satwik,
>>>
>>> I tested a 512x512x144 volume on my laptop, and it took 15 seconds.
>>> So, no, that's not very fast.  The class uses a windowed sinc
>>> interpolator,
>>> which is computationally expensive.  I could add an option to use linear
>>> interpolation.  With linear interpolation it only takes 1 second.
>>>
>>>  - David
>>>
>>>
>>> On Wed, Nov 29, 2017 at 10:29 PM, Satwik <satwik.k8 at gmail.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> Dimensions of my volume is (512, 512, 144).
>>>>
>>>> ///My Code///
>>>> vtkDICOMCTRectifier* m_rectify = vtkDICOMCTRectifier::New();
>>>> m_rectify->SetEnableSMP(true);
>>>> m_rectify->SetVolumeMatrix(d->m_initOrient); //passing orientation
>>>> matrix
>>>> m_rectify->SetInputData(d->m_imageData); //passing image data
>>>> m_rectify->Update();
>>>>
>>>> Regards,
>>>> Satwik K.
>>>>
>>>>
>
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