Matt J

Last seen: Today

7 760 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

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Answered
Curve fitting of growing measurement data set
This might help, https://www.mathworks.com/matlabcentral/fileexchange/24443-slm-shape-language-modeling

ungefär 5 timmar ago | 0

Answered
Splitting a matrix into two smaller matrices in a loop
z=[1;2;4;6;8;10]; for k=1:length(z) ind=z(k):z(k+1); test=My_Data(ind,:); train=MyData; trai...

ungefär 5 timmar ago | 0

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Answered
lsqcurvefit with two functions and same vriables
No, the problem is that YY is not 8x2.

ungefär 5 timmar ago | 0

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Answered
3D Matrix to present the solution
Sol=reshape(Sol,Nx,Ny,Nz);

ungefär 5 timmar ago | 0

Answered
Brace indexing is not supported for variables of this type.
imageNames = {imgFile.name}

ungefär 7 timmar ago | 1

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Answered
color area between two shapes
load(websave('t','https://www.mathworks.com/matlabcentral/answers/uploaded_files/592785/data.mat')) R = 10; C = [0. 0.] ; xc...

ungefär 8 timmar ago | 0

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Answered
how to select proper parameters for "opt.StartPoint" ?
Assuming b is known, the log-model log(yData)=log(c) + a*(log(x)*sin(x*b)^2) is a linear model in a and log( c ). Therefore, i...

ungefär 9 timmar ago | 0

Answered
Filling a 2D area between 3 curves (Hypocycloid)
%radius big (fix) circle R=4; %radius small (rolling) circle r=1; phi=linspace(0,360,1000)*pi/180; phi(end)=[]; %parame...

ungefär 9 timmar ago | 1

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Answered
Elements of matrix after an equation
p = A(:, 1) .* A(:, 2); index=(abs(p)==norm(p,inf)) & p<0; a1=A(index,1); a2=A(index,2);

ungefär 9 timmar ago | 0

Answered
How to get all combinations from this matrix?
ch=['MRWI' 'IDMZ' 'CGBI' 'JKNO']; cht=ch.'; [I{1:4}]=ndgrid(1:4); I=reshape(cat(5,I{4:-1:1}),[],4); combs=...

ungefär 23 timmar ago | 0

Answered
Quadratic programming with just one constraint
We may have to be given your input matrices to reproduce the problem, but since ones(1,d) is full row rank, there shouldn't have...

ungefär 23 timmar ago | 0

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Answered
3D array of rotation matrices multiplied on 2D array of vectors
C=pagemtimes(A, reshape(B.',3,1,[]) ); C=reshape(C,3,[]).';

en dag ago | 1

Answered
vectorize a for loop
This should be pretty well optimized already, r=pdist([xc,yc]);

en dag ago | 1

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Answered
Function with one input and no outputs
printmsg("Hello World") function printmsg(msg) disp(msg) end

en dag ago | 0

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Answered
What is the sampling frequency after convolution?
I want to calculate the convolution of the two signals with conv If you want to convolve with conv() then the signals definitel...

en dag ago | 0

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Answered
detecting rectangle in real images
This works for the one given image. I would need more examples to see if it's a reliable solution. It uses the FEX contribution ...

2 dagar ago | 0

Answered
Plotting a 3d cone
the general cone generators like 'cylinder([0 1])' are not usable for me. I think they are. You just have to reposition the co...

2 dagar ago | 0

Answered
Randomly remove percentage of values above mean in array
A = [set of values]; A_rem=A; index1 = find(A>mean(A)); N=numel(index1); index2 = index1( randi(N,1,round(0.2*N)) );...

2 dagar ago | 0

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Answered
Boolean False when it should be True
dom(8,2) is only 8.3000 to 4 decimal places. You cannot see the differences beyond the 4th decimal unless you use >> format lon...

2 dagar ago | 0

Answered
how do i get MATLAB to extract a specific value in multidimension array or matrix
idx=CHIRPS_SPI3_SM<-1 & CHIRPS_SPI3_SM>-4; extractedValues=CHIRPS_SPI3_SM(idx);

2 dagar ago | 0

Submitted

Further tools for analyzing objects in N-dimensional images
A collection of tools to supplement bwpropfilt, bwareaopen, and the like.

2 dagar ago | 2 downloads |

Question

Axis resizes inconsistently in a TiledChartLayout when you change its TileSpan
In the first example below, I obtain a TiledChartLayout in which all the plots have the same size (which is what I want). Why do...

2 dagar ago | 0 answers | 0

0

answers

Answered
set intervals with starts and ends in two arrays
Because it's homework, I've left some blanks for you to fill in. starts = [ 1 20 30 40]; ends = [3 22 34 41]; D=ends-starts...

3 dagar ago | 0

Answered
How do I check/verify that an array is a certain dimension?
while ~isequal(size(point),[1,2])

3 dagar ago | 0

Answered
Counting Number of Voxels between 2 points without drawing lines
Assuming you have a binarized image and the curve is the only object in that image, [I,J]=find( bwmorph(yourImage,'endpoints'))...

3 dagar ago | 0

Answered
How does the command: real(ifft(fftshift(Y))*N) operate?
All of those oeprations are O(N) except for the IFFT which is O(Nlog(N)). So the chain of operations is O(Nlog(N)) overall.It wo...

3 dagar ago | 0

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Answered
how can i remove objects that are on the edge of another object?
You can use imopen().

3 dagar ago | 0

Answered
How can concatenate matrices with dimension expansion.
permute( cat(3,img1,im2), [3,1,2]);

4 dagar ago | 0

Answered
Plotting a 3D mode shape by revolving 2D datapoints (in the r-z-plane) of an axisymmetric geometry around the z-axis
I can't follow most of what you posted, but if you just want to generate a surface/solid of revolution, you can use cylinder() ...

4 dagar ago | 1

Answered
making a 2d image from 3d shape
It seems like it would be better if you would just generate your spheres direclty as a 3D image volume. Then you could just use...

4 dagar ago | 0