# 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**

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...

11 hours ago | 0

how to remove the tiny white pixels around the rectangles

imopen(yourImage,ones(3))

13 hours ago | 0

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...

17 hours ago | 0

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...

1 day ago | 2

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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(~...

1 day ago | 0

Matrix multiplication along a specified dimension?

B=pagemtimes(A,X)

1 day ago | 0

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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.

2 days ago | 0

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)

2 days ago | 0

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Fit ellipse in 3D space

Another possibility is to use this FEX download, https://www.mathworks.com/matlabcentral/fileexchange/87584-object-oriented-to...

2 days ago | 0

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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...

2 days ago | 0

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...

2 days ago | 0

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...

2 days ago | 1

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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...

2 days ago | 0

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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 ...

2 days ago | 0

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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...

3 days ago | 0

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...

3 days ago | 0

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Submitted

Further tools for analyzing objects in N-dimensional images

A collection of tools to supplement bwpropfilt, bwareaopen, and the like.

4 days ago | 6 downloads |

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...

4 days ago | 1

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...

5 days ago | 0

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Rect function with Array

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

6 days ago | 0

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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','...

6 days ago | 0

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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, ...

6 days ago | 1

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...

7 days ago | 1

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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,...

7 days ago | 0

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 ...

7 days ago | 0

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...

8 days ago | 0

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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...

8 days ago | 0

Concatenate vectors stored in cell array

cell2mat( reshape( yourCell.' ,1,[],27) )

8 days ago | 1

Why ifft results of analytic signal spectrum don't match with theoretical time formula?

The IFFT and the continuous inverse Fourier transform are not the same thing. tau=0.4; t0=2.8; mag=10; Fs=200; dT=1/Fs; ...

8 days ago | 0

| accepted