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Matt J


Last seen: Today
6.314 total contributions since 2009

Professional Interests: medical image processing, optimization algorithms

PLEASE NOTE: I do not read email sent through my author page. Please post questions about FEX submissions in their respective Comments section.

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Answered
making coarse matrix from fine resolution matrix
A 3rd approach, more memory conserving and, I believe, faster than the currently Accepted answer. Z1=randi(100,8640,4320); u...

alrededor de 9 horas ago | 0

Answered
3D image template matching by using (normalized) cross correlation?
I've never used it myself , but you could try this FEX submission, https://www.mathworks.com/matlabcentral/fileexchange/73946-n...

alrededor de 11 horas ago | 0

Answered
making coarse matrix from fine resolution matrix
If you have the Image Processing Toolbox, abc1=imresize(Z1,[3600,1800])

alrededor de 16 horas ago | 1

Answered
find the element in matrix of intersecting vectors
attainedA=( max(a,[],1)==a ); attainedB=( max(b,[],2)==b ); result = c(attainedA & attainedB)

alrededor de 16 horas ago | 1

| accepted

Answered
Quadprog message: The problem is non-convex
You cannot submit a problem that is borderline convex to quadprog if it is using an algorithm that expects convexity. If you do,...

alrededor de 17 horas ago | 0

Answered
How to define a plane by matrices instead of a function?
For example, A = [104,122,111]; B = [253,122,153]; C = [104,124,111]; normal=normalize( cross(A-B,A-C),'norm'); %calcul...

1 día ago | 1

| accepted

Answered
When using the cftool, should I use Trust Region or Levenberg-Marquardt?
You can read here about the relative limitations of the 2 algorithms, https://www.mathworks.com/help/optim/ug/lsqcurvefit.html#...

1 día ago | 0

Answered
Need Math to Rotate XYZ Point Around A-B Rotary Axes
See Rodrigues' formula, https://en.wikipedia.org/wiki/Rodrigues%27_rotation_formula Also, though you are apparently not worki...

1 día ago | 0

Answered
How to run fmincon using following function?
With no constraints, it would simply be, x=ones(200)/(-c*B);

2 días ago | 0

| accepted

Answered
No solution found when solving 3 non linear equations
A numerical sweep also gives evidence that there is no solution [x1,x2,x3]=ndgrid(linspace(-pi,+pi,512)); F1=cos(-x1+x2)+c...

3 días ago | 0

Answered
How do you call an inline or anonymous function within cellfun?
I reverted back to the for loop This might be faster than the for-loop, allB=[B{:}]; idx=ismember(allB,A); Blens=cellfun('l...

3 días ago | 1

Answered
How do you call an inline or anonymous function within cellfun?
But would still like to know how to use anonymous functions within cellfun There's no difference. Since findVal is already a fu...

3 días ago | 0

| accepted

Answered
Converged to an infeasible point.
The initial guess you have chosen x0 = [1,1,1,1,1,1,1,1]; seems very arbitrary. You should devise an initial guess more likely...

4 días ago | 0

| accepted

Answered
Matrix sequence manipulation for multiple value assignment
e=1:numel(A); lidx= any(idxes(:,1)<=e & e<=idxes(:,2),1); A(lidx)=1;

4 días ago | 0

Answered
Matrix sequence manipulation for multiple value assignment
If the intervals will always be disjoint, A=zeros(20,1); n=numel(A); A(idxes(:,1))=1; A(idxes(:,2)+1)=-1; A=cumsum(A(1:n)...

4 días ago | 0

Answered
Getting the coordinates of vertices of an A4 sheet with coins on it, for its further projective transformation and coin detection
The Computer Vision Toolbox has a few corner point detector apps, https://www.mathworks.com/help/vision/ug/point-feature-types....

4 días ago | 0

Answered
Relocate a value of a vector.
A=[1 2 3 4 5 6 7 8 9 0]; i=2; %position removed j=7; %target position B=A; k=i<j; B(i)=inf; C = [B(1:j+k-1),A(i),...

6 días ago | 2

| accepted

Answered
table less than operator
Are you sure you do not instead want to compare the content of a variable in the table to something?... yes this what I'm trying...

6 días ago | 0

Answered
Why is N not being displayed?
Because the loop condition is never satisfied and therefore nothing within it is ever executed. I think you meant to have, whil...

6 días ago | 0

| accepted

Answered
Displaying information about the data set by clicking on its plot and then show a value that is associated with the (x,y) point
.... set(dcm,'UpdateFcn',@(t,e) myupdatefcn(t,e,x,y) ); function txt = myupdatefcn(~,event,xdata,ydata) pos = get(eve...

6 días ago | 0

| accepted

Answered
Getting the linear portion of a non-linear curve
I'm not sure why a 2nd derivative test wouldn't have worked, as long as your points are noiseless: i=find( abs(diff(x,2))>somet...

7 días ago | 1

Answered
How to return the smallest vector.
If you "have them" in cell array form, then you could do something like this: >> vectors={[3 4 5],[1,2],[5 6 7 8]} vectors =...

7 días ago | 0

| accepted

Answered
a problem with setting fmincon options?
I would guess that you entered your options object as the 9th input argument to fmincon when it really should be the 10th. If yo...

7 días ago | 0

| accepted

Answered
set Precision in lsqcurvefit
You cannot do such a thing with lsqcurvefit. What you describe would require that you rewrite your objective function and bounds...

7 días ago | 2

Answered
Delete part of an image
[m,n]=size(oldImage); x=(1:n); y=(1:m).'; mask = (x-innerCenterX).^2+(y-innerCenterY).^2>=innerRadius^2 & ... (x...

7 días ago | 2

| accepted

Answered
Find the orientation of the skeletonized image
You can use houghlines to get the endpoints of all the line segments in the image. From that, you can easily calculate their slo...

7 días ago | 0

Answered
Using cell array to define Argument list in function Handle
That is not the right approach. You should be taking advantage of the fact that this is Matlab, and that your variables are allo...

8 días ago | 0

Answered
Divide plane into two separate planes
Let b1 and b2 be basis vectors for the plane and let x0 be a point in the plane. Then, for example, x0(:) + b1(:)*randn(1,N) + ...

8 días ago | 0

Answered
how to plot values that only fall within a range?
KPH_70 = mean(Y(FVY)); yyaxis left plot(X(FVY),Y(FVY)); yyaxis right plot(X(FVY),KPH_70*ones(size(FVY)));

9 días ago | 0

| accepted

Answered
How to pass a vector to a function that creates matrix
>> b=[1 2 3]*10; >> T=@(i) [b(i)+9 , 8 ; 8 , 7 ]; >> T(3) ans = 39 8 8 7

9 días ago | 0

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