# Matt J

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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**Content Feed**

Transform coordinates into pixel

Use getframe and writeVideo like in this example: https://www.mathworks.com/help/matlab/ref/videowriter.writevideo.html#mw_6dab...

17 minuter ago | 0

Extracting tables within a cell.

Your files all seem to be identical (apart from some of the header data), so it is no surprise that every iteration seems to giv...

32 minuter ago | 0

Question

Why don't getframe RGB codes agree with plotted polyshape RGB codes?

In the code below, I have computed the RGB color code of the square as seen in both a polyshape plot (polyshapeRGB) and as seen ...

ungefär 7 timmar ago | 1 answer | 0

### 1

answerLocate two neighboring nodes in space so as to divide the matrix into two

load xydata xy %Original 3D data mapped to 2D xy=xy(tspsearch(xy,5),:); %tspsearch is on the file exchange P=polyshape(xy,...

ungefär 9 timmar ago | 0

Loading multiple structure from a folder

It is because not all of the sub-structures mydata(n).data have the same fields. If you contest that, attach the mydata variable...

en dag ago | 0

| accepted

Can a ROI shape (ie. a Rectangle made by drawRectangle()) be a property of a class?

You need to specify the complete class name: classdef device properties tag string shape images.ro...

en dag ago | 0

How to create struct from fieldnames and values cell arrays for code generation ?

Does it support transpose for normal arrays? If so, then you might be able to do, list_fields = {'a'; 'b'; 'c'; 'd'}; % the fu...

en dag ago | 0

Four-parameters optimization of a 1D function: wrong values

I would recommend using fminspleas, https://www.mathworks.com/matlabcentral/fileexchange/10093-fminspleas with INLP=[p2,p3,p4...

en dag ago | 0

Solve for A matrix in Ax = 0

n=numel(x); mask=tril(triu(ones(n),-1),+1); %tridiagonal mask A=optimvar('A',[n,n]); prob = eqnproblem; prob.Equation...

2 dagar ago | 0

| accepted

negative value structural similarity index

A negative SSIM value means the values in those regions tend to be negatively correlated. When X goes low, then Y tends to go hi...

3 dagar ago | 0

How to handle imagedatastore when input and response have different dimension?

Modify the trntf_input, trntf_label datastores' ReadFcn so that when it reads in the image, it wraps it in a 1x1 cell array. S...

4 dagar ago | 0

| accepted

How to plot 3D plane of surface with 3 coordinates data?

You can use planarFit, from this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-tools...

4 dagar ago | 1

| accepted

Cure fitting - lsqnonlin

I initially inputted my guess, lower bound, and upper bound with the true optimized values obtained from a published paper. Surp...

4 dagar ago | 1

What would be the equation of the following surface?

You could try fitting a 2D Gaussian surface to it, e.g., with this FEX download, https://www.mathworks.com/matlabcentral/fileex...

4 dagar ago | 0

Finding Transformation Matrix of a viewer3d object

I think the 3x4 camera projection matrix P would be, h=gca(); camz=h.CameraTarget-h.CameraPosition; camy=-h.CameraUpVector; ...

4 dagar ago | 1

| accepted

Uploading .mat files that contain nested structs into a datastore

This example shows how to use a fileDataStore to read partial data from a .mat file https://www.mathworks.com/help/matlab/ref/m...

4 dagar ago | 0

Which optimization tool should be used for solving my convex optimization problem?

If, as you seem to, you have a non-quadratic (and therefore also nonlinear) convex objective function, then you must use fmincon...

5 dagar ago | 0

Fixed-distance of legend outside plot axes

is there any "simple" parameter (i.e., not position) which controls the vertical distance between the legend box and the upper e...

5 dagar ago | 1

| accepted

the arc using the chord

Assume the chord is of length L and, with no loss of generality, assume also that it is aligned with the x-axis with end points ...

5 dagar ago | 1

Dot Multiplication in MATLAB

For matrices A and B, the rule is generally that A.* B is element-by-element multiplication a(i,j).*b(i,j), which means that nor...

5 dagar ago | 1

| accepted

Find paths in graph that satisfy specific condition

s=[17,17,17,18,18,19,19,20,20,21,21,22,22,23,23,24,24,25,25,26,26,27,27,28,28,29,29,30,30]; t=[18,19,20,21,22,23,24,25,26,27,28...

5 dagar ago | 0

| accepted

Getting error in fmincon with below code how to correct it

You seem to be trying to minimize over a space of functionals, F. You cannot do that with fmincon. The objective must be a funct...

5 dagar ago | 0

How to plot a grouped bar chart?

https://www.mathworks.com/help/matlab/ref/bar.html#bthxce9

6 dagar ago | 1

| accepted

Subdivide a figure with a grid (as in Timescope)

Something like this, perhaps? t=tiledlayout(2,2); for i=1:4, nexttile(t), plot(rand(1,4)); grid on; end background=axes('Po...

6 dagar ago | 0

vectorized operations on symbolic functions

syms x1 x2 x3; % symbolic variables y = x1^3/3 + x2^2/2 - x3; % symbolic function y X = rand(500,3); % each row representing a...

6 dagar ago | 1

How to add an image to the current axes without replacing existing plots

You can use hold fcontour(@(x,y) (x-50).^2+(y-50).^2,[20,80],'m'); hold on imshow(imread('cameraman.tif')); hold off h=gc...

6 dagar ago | 0

Restart Fmincon Optimization from Checkpoint File

No, unfortunately. Restarting from the last point is probably the best you can do. Although, apart from the interior-point algor...

6 dagar ago | 0

| accepted

Image semantic segmentation dimension layer why not match input and output

Below is what analyzeNetwork gives. Only you know what you want the dimensions of each of your activation maps to be. Tell us at...

6 dagar ago | 0

Combining two arrays using a seconds order

number = randperm(10, 10) number2 = randperm(10, 10) I=ismember(number2,number(1:5)); number(1:5)=number2(I)

6 dagar ago | 0

| accepted

How can I calculate the unique centroids along with its radius range ?

load data; threshold=2; %Example input T=sortrows(table(Centroid, Radius),2) Centroid=T.Centroid; Radius=T.Radius; D=pdi...

6 dagar ago | 1

| accepted