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# Steve Eddins

### MathWorks

825 total contributions since 2006

MATLAB user since 1987. MathWorker since 1993. Amateur French horn player. MATLAB design and development, image processing algorithms.

Image processing blog: https://blogs.mathworks.com/steve/

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superimpose matrices (n,n,m) to (n,n,1)
Here are some options. Compute and plot the maximum value at each pixel: imagesc(max(a100,[],3)) Compute and plot the minimum...

4 days ago | 0

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Image conversion from uint16 to uint8 mismatch
im2uint8 is using a scale factor of (255/65535), not 1/256. Note that scaling the maximum of the uint16 range, 65535, by 1/256 ...

4 days ago | 1

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How do I map array values on a logical array
Use logical indexing. C = zeros(size(B)); C(logical(B)) = A

4 days ago | 1

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Create a 7x7 convolution kernel which has an equivalent effect to three passes with a 3x3 mean filter.
Convolution is associative: So, your 7x7 convolution kernel would be the convolution of the mean filters: Use the 'full' o...

5 days ago | 0

pgm image lossless compression
Write the image to a PNG file. The PNG format uses lossless compression. imwrite(A,'myfile.png') Read it back in using imread....

5 days ago | 0

Shade area in graph for multiple y-axes
I rearranged your code a bit, putting both of the first two plotting functions (patch and plot) after the call to yaxis left. I ...

11 days ago | 0

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How to add percent change in barplot?
If you want text labels instead of a line plot (Cris' suggestion), then try this code. It gets the Bar object as the output argu...

12 days ago | 1

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Neighbor and center points of matrix
See my 25-Feb-2008 blog post called "Neighbor indexing" for a general technique. You'll need to pay careful attention to what h...

17 days ago | 1

Fourier Transform of a signal
The fft function in MATLAB computes something called the discrete Fourier transform. Your problem here is asking you to find som...

17 days ago | 0

Solved

Matrix Pattern 1

19 days ago

How can I create a 3D array?
Try something like this: for i = 1:n-1 next_image = uigetfile('*p*'); ImageArray = cat(3,ImageArray,next_image); end...

19 days ago | 0

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customize export setup to generate SVG
Try this: h = findall(fig,'-property','FontName'); set(h,'FontName','San Serif'); print(fig,'-dsvg','mygraphic.svg')

23 days ago | 0

You're looking for a file called rwb.mat. Once you find it, put it in your current working folder or in a folder that's on the M...

1 month ago | 1

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How to get the x and y coordinates of the each marker in a frame?
I used the Color Thresholder app to get code that segments your image based on the green color of the markers. Then I used regio...

1 month ago | 0

Give an unknown number of parameters to feval
Put your parameters in a cell array and then use the syntax that expands a cell array into a comma-separated list: out = feval(...

1 month ago | 0

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Infinite Recursion in own Levenberg-Marquardt Code
I see that korrektur is calling itself recursively. I noticed also that the recursive call appears to be identical to the top-le...

1 month ago | 1

Text increments of the x-axis
Sure, you can set the XTicks property of the axes object directly. ax = gca; ax.XTicks = [1 2 3]; A shortcut for this is: xt...

2 months ago | 0

Solved

Find nth maximum
Find nth maximum in a vector of integer numbers. Return NaN if no such number exists. x = [2 6 4 9 -10 3 1 5 -10]; So ...

2 months ago

Solved

Create an index-powered vector
Given a input vector x, return y as index-powered vector as shown below. Example x = [2 3 6 9] then y should be [...

2 months ago

Solved

Symmetry of vector
Determine whether the vector is symmetric or not (vector could be even or odd in length). For example: x = [1 2 3 3 2 1] ...

2 months ago

imshow doesn't display png image file
Your image is stored in the PNG file as unsigned 16-bit integers. When imshow displays a uint16 image, it uses the unsigned 16-b...

2 months ago | 1

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Solved

Create an n-by-n null matrix and fill with ones certain positions
The positions will be indicated by a z-by-2 matrix. Each row in this z-by-2 matrix will have the row and column in which a 1 has...

2 months ago

How to plot particle trajectories and normalise to 0,0 origin?
Here is one way you could do it. Read in the whole Excel file as a table. Then, in a loop, extract the particle data for each tr...

2 months ago | 1

From for to While loop
Here is one way to convert a typical MATLAB for loop to a while loop: for i = 1:N ... end i = 1; while i <= N .....

2 months ago | 0

Select data from CSV file based on character in position, then read that character and next 2 character, of different read that character and next 3
MATLAB has a number of functions that can automatically read and parse CSV files and return the results in a useful form. Try re...

2 months ago | 0

Solved

QWERTY coordinates
Given a lowercase letter or a digit as input, return the row where that letter appears on a <http://en.wikipedia.org/wiki/Keyboa...

2 months ago

Solved

The Tower of Hanoi
In the <http://en.wikipedia.org/wiki/Tower_of_Hanoi Tower of Hanoi problem> with 3 rods (1, 2 & 3), the goal is to move a tower ...

2 months ago

Solved

Can we make a triangle?
Given three positive number, check whether a triangle can be made with these sides length or not. remember that in a triangle su...

2 months ago

Solved

Find the sides of an isosceles triangle when given its area and height from its base to apex
Find the sides of an isosceles triangle when given its area and the height from its base to apex. For example, with A=12 and ...

2 months ago