[Insight-users] Re: matrix and vector

Luis Ibanez luis . ibanez at kitware . com
Mon, 13 Oct 2003 22:26:23 -0400


Hi Bing,

(0) The operator [] in the itk::Matrix return a row of the matrix.
     http://www . itk . org/Insight/Doxygen/html/classitk_1_1Matrix . html#a9
     the vnl_matrix has similar access methods (with the operator[]).
     Please look at
     http://www . robots . ox . ac . uk/~awf/vxl/book/book_5 . html

(1) You can interpolate an image of Vector using the
     VectorLinearInterpolateImageFunction class:
http://www . itk . org/Insight/Doxygen/html/classitk_1_1VectorLinearInterpolateImageFunction . html


(2) Yes,
     You just need to write the appropriate PixelAccessor.




Regards,


    Luis


---------------
Bing Jian wrote:
> Hello,
> 
>   Can anybody help me following questions?
> 
> (0) Is there an easy way to read/write one column or row vector
> of a matrix?
> (1) Does interpolater accept vector or matrix image as input?
> (2) Can we extract vector image from matrix image
> in the same way as VectorPixelAccessor?
> 
>   Thanks in  advance!
> 
> 
> On Thu, 9 Oct 2003, Bing Jian wrote:
> 
> 
>>Hello,
>>
>>   Is there an easy way to assign a vector to ith row or col of
>>matrix?
>>   e.g.
>>        itk::Matrix<T, m, n> A;
>>        itk::Vector<T, n> x;
>>        A[i] = x;
>>
>>  I looked through the reference page of itk::Matrix, only found
>>
>>T *  operator[] (unsigned int i)
>>const T *  operator[] (unsigned int i) const
>>
>>  So do we need to use GetVnlMatrix()?
>>
>>
> 
> 
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