Matt J
Professional Interests: medical image processing, optimization algorithms
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Content Feed
Is it possible to reconstruct an image from the number of pixel counts and bins information?
As Walter has shown, it is not an invertible mapping, however, if you use histcounts() instead, there is enough information for ...
1 hour ago | 0
how to find total combination of 5 elements in composition?
Here's an old routine from John D'Errico. I can't find it on the File Exchange anymore, for some reason. combinations=diophanti...
4 hours ago | 0
| accepted
How to remove rows in a nested for loop?
It should start with the column (and therefore the Detected_center point) with the overall shortest distance to a Original_cent...
7 hours ago | 0
Efficient matrix multiplication with weights
A more memory efficient solution is as follows. It has a loop, but is still highly vectorized. Wt=W.'; At=A.'; T=toeplitz(1:N...
9 hours ago | 0
Is applying a binary operator (+,-,*,/) to char arrays supported by MATLAB or just a "trick"
I can't find the documentation, but binary operators in Matlab can't define themselves. It had to be deliberate. Also, the char...
9 hours ago | 0
Efficient matrix multiplication with weights
Using sepblockfun() from, https://www.mathworks.com/matlabcentral/fileexchange/48089-separable-block-wise-operations T=toepli...
10 hours ago | 0
Losing pixels with imrotate
So my question was: is there any other way to rotate the images without losing pixels? If you use 'linear' or 'cubic' interpol...
12 hours ago | 0
| accepted
Calculate average between min and max numbers in column 3 depending on values in column 2, for each value in column 1
A=yourMatrix; idx=A(:,1)==7; B=A(idx,:); [~,idx]=maxk(B(:,2),5); C=B(idx,3); result=0.5*(max(C)+min(C))
1 day ago | 1
| accepted
Iteratively fill structure with custom class objects
I'm puzzled as to why your custom_class() constructor requires the same input argument twice, but this is how I'd do it. rows =...
1 day ago | 0
Count the number of times a value repeats between certain rows in a matrix.
A=[2,5,15,65,102; 2,65,1,105,55; 65,104,15,19,5]; skip=1; A1=A(1:end-skip,:); A2=A(skip+1:end,:); M=size(...
1 day ago | 0
| accepted
How to write an optimization constraint related to neighbors of a node in a graph
You can get the graph adjacency matrix A from the adjacency() command, https://www.mathworks.com/help/matlab/ref/graph.adjacenc...
1 day ago | 0
| accepted
Complex non-linear least squares fitting of impedance data
Because your model function is linear with respect to x(1) and 1/x(2), it would be beneficial to download fminspleas, https://w...
1 day ago | 0
random matrix with a minimum number difference for adjacent numbers accepted
Why not as follows? min_diff=0.1; R=rand(1,6); R=R./min(abs(diff(R)))*min_diff; abs(diff(R))
2 days ago | 0
I need to change the frequency domain of a DFT
stem(2*pi*f,abs(shx),'r')
2 days ago | 1
| accepted
Count number of rows in a matrix based on frequency of one element and value of another element
nnz( matrix(:,1) == 10 & matrix(:,2) > 5 );
3 days ago | 0
| accepted
How to improve calculation time for a huge matrix?
When speed matters, avoid symbolic math. Also, download https://www.mathworks.com/matlabcentral/fileexchange/74956-ndgridvecs ...
3 days ago | 0
How to remove rows in a nested for loop?
For Euclidean distance, discard=any( pdist2(Original_center,Detected_center)<Threshold ,2); Original_center(discard,:)=[];...
3 days ago | 0
Creating a inclined plane with an adjustable dome pattern cutout of it.
You can rotate and replicate the single dome using hgtransform, similar to this example, https://www.mathworks.com/help/matlab/...
4 days ago | 0
Question
Height of a figure spontaneously changes.
When I run the following code, I find that the OuterPosition properties of both figures report the same height and width, as exp...
4 days ago | 2 answers | 0
2
answersIntegral of the product of integrals
I=@(y,f) integral( @(x)f(x,y), a, b); I123=@(y) I(y,f1) .* I(y,f2) .* I(y,f3); integral(I123, c, d)
4 days ago | 0
| accepted
How can I find the distance between adjacent blobs in a segmented image?
Here's one way. mask=imclose(mask, strel('disk',12) ); imshow(mask) blobProps = regionprops( mask , 'Centroid'); blob...
4 days ago | 0
Solving Equaiton with multplying power
LHS=[0 0 1; -1 0 0; 1 1 -3]; RHS=[0;1;-3]; XYZ=LHS\RHS
5 days ago | 1
How to only extract part of the folder name?
str='Run 12-27-56.Adaptive PIV.6uqqm6yu' d2=digitsPattern(2); extract(str,d2+"-"+d2+"-"+d2)
6 days ago | 1
| accepted
How do you reset a persistent variable?
dpb 's answer resolved it..
6 days ago | 0
| accepted
How to remove rows in a nested for loop?
discard=ismembertol(Original_center,Detected_center,Threshold,'ByRows',1,'DataScale',1); Original_center(discard,:)=[];
6 days ago | 0
How to turn a function handle with 3 inputs (1 variable and 2 parameters) and then assign the inputs parameters and get a function handle with one input? ?
But, this is computationally very expensive for my super big expressions. What if you use the optimize flag? g=matlabFunction...
6 days ago | 0
Question
How do you reset a persistent variable?
The documentaiton says that a persistent variable is reset when the function is cleared from memory. Why then do I not see the p...
6 days ago | 1 answer | 0
