Steve Eddins

Last seen: 1 day ago

MathWorks

832 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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Answered
Code is showing Undefined function 'pixelHull' for input arguments of type 'double'.
I wrote a function called pixelHull as part of my 16-Mar-2018 blog post. You can find the function listing near the bottom of th...

3 days ago | 0

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Answered
Binarize image for specific colour
Use the Color Thresholder app to generate the code needed to do this segmentation. See my 14-Oct-2019 and 25-Apr-2014 blog posts...

25 days ago | 0

Answered
Plotting signal of a region of interest
A possible explanation is that you have a variable called "size" or "mean" in your workspace. For example, if you have a variabl...

28 days ago | 0

Answered
How to apply a threshold value to the cell array
I think writing a for-loop would be most straightforward way to go. Something like this: for k = 1:numel(C) C_k = C{k}; ...

30 days ago | 0

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Answered
How to change the font of a pie chart?
The text labels created by the pie function are not controlled by the font properties of the containing axes object. They are in...

1 month ago | 1

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Answered
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...

2 months ago | 0

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Answered
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 ...

2 months ago | 1

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

2 months ago | 1

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Answered
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...

2 months ago | 0

Answered
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....

2 months ago | 0

Published

How imshowpair and imfuse work
In this post, I'll explore how imshowpair and imfuse work.Reason: I was curious.Last month, I wrote about registering...

2 months ago

Answered
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 ...

2 months ago | 0

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Answered
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...

2 months ago | 1

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Answered
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...

2 months ago | 1

Answered
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...

2 months ago | 0

Solved

Matrix Pattern 1

2 months ago

Answered
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...

2 months ago | 0

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

2 months ago | 0

Published

Registering Hand-Held Pictures
The typical modern French* horn, pictured below, has about 23 total feet of tubing. At the beginning and the end, the tubing...

2 months ago

Solved

Double the next and alternate sign

2 months ago

Answered
load rwb gives error
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...

3 months ago | 1

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Answered
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...

3 months ago | 0

Answered
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(...

3 months ago | 0

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Answered
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...

3 months ago | 1

Answered
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...

3 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 ...

3 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 [...

3 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] ...

3 months ago

Answered
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...

3 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...

3 months ago