Steve Eddins

Last seen: 3 dagen ago

MathWorks

843 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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Published

Plotting a* and b* colors
Today's blog post comes from planning one topic, but then taking a sharp left turn and doing something else completely. I...

20 dagen ago

Answered
Having graycomatrix rescaling problem
Here is the doc for the NumLevels parameter: Number of gray levels, specified as an integer. For example, if NumLevels is 8, gr...

ongeveer een maand ago | 0

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Answered
How to find the center position under the saturation spot signal
Try converting the image to binary using imbinarize and then using regionprops to compute the centroid. rgb = imread('image.bmp...

ongeveer een maand ago | 0

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Answered
How to bold x axis labels
Try setting the TickLabelsInterpreter property to 'tex', like this: plot(1:10) ax = gca; ax.XAxis.TickLabelInterpreter = 'tex...

2 maanden ago | 0

Answered
three difference vectors and plots
I have copy-pasted your code below, exactly as entered in your question. It runs and produces the plot with no error. I suggest ...

2 maanden ago | 2

Answered
Problem with datetime and daily values
Use a timetable and the retime function. >> T = readtable("data.xlsx"); >> head(T) ans = 8×5 table Date ...

2 maanden ago | 0

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Answered
What is the best way to count the occurrences of two table columns together?
In my previous answer, I forgot that grpstats is in the Statistics and Machine Learning Toolbox. Here is an answer using groupsu...

2 maanden ago | 1

Answered
What is the best way to count the occurrences of two table columns together?
I think grpstats will do what you want: >> grpstats(T,["A" "B"]) ans = 4×3 table A B Grou...

2 maanden ago | 0

Answered
Find peaks not working on my data set
I suspect the issue is with the x-coordinates that you are using to plot the peaks. You are plotting the peaks against the indic...

2 maanden ago | 1

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Answered
Assign values in a matrix
One idea is to use a timetable and the retime function. Suppose I have the following matrix for a 4-minute charge and a 3-minute...

2 maanden ago | 0

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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 maanden ago | 0

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Published

FFT Spectral Leakage
A MATLAB user recently contacted MathWorks tech support to ask why the output of fft did not meet their expectations, and...

3 maanden ago

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...

3 maanden 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...

3 maanden 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}; ...

3 maanden 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...

4 maanden 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...

4 maanden 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 ...

4 maanden 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

4 maanden 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...

4 maanden 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....

4 maanden 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...

4 maanden 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 ...

4 maanden 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...

4 maanden 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...

5 maanden 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...

5 maanden ago | 0

Solved

Matrix Pattern 1

5 maanden 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...

5 maanden 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')

5 maanden 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...

5 maanden ago