Hi YiQiang,
> 1)what difference are between InPlaneBifurcationVectorAngles and ICA angle?
The InPlaneBifurcationVectorAngles are the angles between the up-normal vector
and a branch vector projected onto the bifurcation plane.
The ICA angle is the angle between the ICA and ECA vectors projected onto the
bifurcation plane. So, by summing the angle between the ICA branch vector and
the up-normal and the ECA branch vector and the up-normal you get the ICA
angle. Note: here I wrote "sum" because I'm referring to the angles absolute
value, but it's really the difference of the signed angles (since the ICA
branch and the ECA branch are on opposite sides of the bifurcation up-normal,
so one angle will come out positive and the other negative, by the convention
used in vmtk).
The reason why we don't spit the ICA angle directly is just our wish to make
the tool generic and not specific to the carotid bifurcation.
> 2)in the result of the vector (BifurcationVectors, InPlaneBifurcationVectors,
> OutOfPlaneBifurcationVectors) by VMTK (as an attachment), each part has three
> groups. and how to get the angle from the vector by VMTK? or do i need to use
> the other tools (such as Paraview) to caculate the angle value.
You get both vectors and angles. In fact, the InPlaneBifurcationVectorAngles
are angles in radians, while the InPlaneBifurcationVectors are the vector
components from which the angle is computed.
> 3)for the ICA angle, i need to get the difference between the two downstream
> inplane angles. but the InPlaneBifurcationVectors has two downstream groups
> vector [(--0.27,0.18,2.60), (0.60, -0.50.0.89)] and how to distinguish and
> control these vectors.
You should look at the InPlaneBifurcationVectorAngles and take the difference
(see point above) between the angles for group 2 and 3 (which correspond to the
ICA and ECA - assuming you selected the output target point of the ICA as first
when extracting centerlines).
So, in your case, ICA = 0.26687 - (- 0.608927) = 0.875797 (in radians) = 50.18
(in degrees)
Hope this clarifies it.
Luca
On Mar 29, 2013, at 4:20 PM, qiang zeng wrote:
> Hi Luca,
> Thank you for your reply.
> I have already saw the "Computing bifurcation geometry" section. but i have
> some doubt:
> 1)what difference are between InPlaneBifurcationVectorAngles and ICA angle?
> 2)in the result of the vector (BifurcationVectors, InPlaneBifurcationVectors,
> OutOfPlaneBifurcationVectors) by VMTK (as an attachment), each part has three
> groups. and how to get the angle from the vector by VMTK? or do i need to use
> the other tools (such as Paraview) to caculate the angle value.
> 3)for the ICA angle, i need to get the difference between the two downstream
> inplane angles. but the InPlaneBifurcationVectors has two downstream groups
> vector [(--0.27,0.18,2.60), (0.60, -0.50.0.89)] and how to distinguish and
> control these vectors.
>
> Best,
> YiQiang
>
>
> --- 13年3月29日，周五, Luca Antiga <luca.ant...@gmail.com> 写道：
>
> 发件人: Luca Antiga <luca.ant...@gmail.com>
> 主题: Re: [vmtk-users] How to calculate the ICA angle or planarity angle in
> VMTK or Paraview
> 收件人: "qiang zeng" <zengqiang2...@yahoo.com.cn>
> 抄送: vmtk-users@lists.sourceforge.net
> 日期: 2013年3月29日,周五,下午9:35
>
> Hi YiQiang,
> the angles you get from vmtk are explained in
> http://www.vmtk.org/Tutorials/GeometricAnalysis/,
> "Computing bifurcation geometry" section.
>
> The ICA angle is the difference between the two downstream inplane angles,
> while the planarity angle
> is the difference between the upstream and downstream out of plane angles.
>
> Hope this gives you a hint
>
>
> Luca
>
>
>
> On Mar 28, 2013, at 9:10 AM, qiang zeng wrote:
>
>> Dear VMTK users,
>> In my works, I need to calculate the ICA angle and planarity angle like the
>> Stroke 2005 paper. but I didn't get the result from the Paraview.
>> Does anyone know a way to do this?
>>
>> Thanks in advance!
>> Best wishes,
>> YiQiang Zeng
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