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Matt J


Last seen: Today Active 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
cant seem to make the background fully black
A=imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1141370/original.png'); B=bwconvhull(edge(A),'object...

circa 19 ore ago | 1

Answered
cant seem to make the background fully black
A=imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/1141370/original.png'); B=imquantize(A,multithresh(A...

circa 20 ore ago | 1

| accepted

Answered
How to determine if a 3D line segment intersects a side of a 3D rectangular prism?
You can also use Siddon's algorithm https://aapm.onlinelibrary.wiley.com/doi/epdf/10.1118/1.595739 which will compute the int...

1 giorno ago | 0

Answered
how to remove the tiny white pixels around the rectangles
imopen(yourImage,ones(3))

2 giorni ago | 0

Answered
how to define a matrix element in matlab
B(1:2,1:2)=A

2 giorni ago | 0

| accepted

Answered
create a random matrix that satisfies specific criteria (graph theory)
Just permute the rows and columns of the original adjacency matrix, A, [~,is]=sort(rand(264),2); for k=1:264 A(k,:)=A(k,is...

2 giorni ago | 0

Answered
How to determine if a 3D line segment intersects a side of a 3D rectangular prism?
You can use intersectionHull() in this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/30892-analyze-n-dimen...

3 giorni ago | 2

| accepted

Answered
Can you please help me to get the square root of the sum of squares of the second column in the text file ?
Your attachment didn't make it, but assuming it's called yourFile.txt, [~,col]=readvars('yourFile.txt'); result = norm(col(~...

3 giorni ago | 0

Answered
Matrix multiplication along a specified dimension?
B=pagemtimes(A,X)

3 giorni ago | 0

| accepted

Answered
Why do I get an error using "-" along with the message "too many output arguments" when using fmincon?
You have not shown us fValue2, but more than likely, it does not specify any output arguments to be returned.

3 giorni ago | 0

Answered
Extract the bigger number of values from the previous one in an array
Easier to do, Data = rand(1,15) X=10*(diff(Data)>0)

3 giorni ago | 0

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Answered
Fit ellipse in 3D space
Another possibility is to use this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-to...

3 giorni ago | 0

| accepted

Answered
Help using fmincon to find the 2 support locations (x1,x2) that minimize maximum bending moment
I need to minimize the maximum bending moment from 0 to L Do you mean the maximum from among [b1 b2 b3]? If so, you probably wa...

3 giorni ago | 0

Answered
Find the key for vector transformation
See Example 2: Optimal Reordering of Points in the Examples tab of https://www.mathworks.com/matlabcentral/fileexchange/52795-c...

4 giorni ago | 0

Answered
How to create a column vector repeating the same character n times?
and has the same character repeating in each row like 'on'. 'on' contains two characters. Repeating it for N rows would give a...

4 giorni ago | 1

| accepted

Answered
Removal of the the edges from the node of a graph
You want to remove the edges but keep the node itself? If so, G=rmedge(G,outedges(G,nodeID)) If you want to remove the node an...

4 giorni ago | 0

| accepted

Answered
How to obtain and plot perpedicular lines using the gradient of a function
Your plot is correct. The lines just don't look perpendicular because of the plot aspect ratio. x = linspace(-2,1,100)'; y ...

4 giorni ago | 0

| accepted

Answered
Fit ellipse in 3D space
I am searching for intersection of plane and ellipsoid If that is the ultimate goal, you should just rewrite the ellipsoid equa...

4 giorni ago | 0

Answered
How can I transparent my gaussian distribution and convert to a transparent ellipse
You can extract the points on the contour lines using tis FEX download https://www.mathworks.com/matlabcentral/fileexchange/740...

4 giorni ago | 0

| accepted

Submitted


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

5 giorni ago | 6 downloads |

Answered
How can I remove object in binary image by using a mask
You can use bwlmaskpropfiltn() from this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/90762-further-tools...

5 giorni ago | 1

Answered
How can I include the legends within the for loop and how can I set the xticks in MATLAB?
So, how can I include legends with the for loop instead of writing it outside? You are assuming here that the for loop is the o...

6 giorni ago | 0

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Answered
Rect function with Array
function [y] = rect(T0, A, t) y= ((t >= -T0/2) & (t <= T0/2)) * A; end

7 giorni ago | 0

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Answered
Count the occurrence of each element in an array
string = 'I am happy'; [N,e]=histcounts(double(string),32:130); table(char(e(N>0)'),N(N>0)','VariableNames',{'Character','...

8 giorni ago | 0

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Answered
Why the outcome of my code is just white image?
Give imshow() a second argument to see the desired grayscale range. img1=im2gray(imread('cameraman.tif')); kernel = ones(3, ...

8 giorni ago | 1

Answered
if and sum not working together
Because the sum cannot be done exactly in floating point. Therefore you need a tolerance, a = zeros(10,1)+0.001; b = sum(a) i...

8 giorni ago | 1

| accepted

Answered
what exactly norm(x) function do?
Assuming you only care about p=2, If you already have code that computes norm(x) for real x, you can extend it to complex x via,...

9 giorni ago | 0

Answered
Formula for norm(x)
Assuming you're only interested in p=2, if you already have code that computes norm(x) for real x, you can extend it to complex ...

9 giorni ago | 0

Answered
Multiple Image reconstruction with real and imaginary part in 2d array
What is the name of the variable stored inside the .mat files? If I assume it is X, then, a_real = load("img_real.mat").X; a_i...

9 giorni ago | 0

| accepted

Answered
Equality between 2 floats not recognized when using <= relational operator
I feel pretty confident that either Money_types or Var2 is not truly equal to 0.05 in spite of what you suppose. It may appear t...

9 giorni ago | 0

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