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# Constantino Carlos Reyes-Aldasoro

### City, University of London

Last seen: 14 days ago Active since 2016

Senior Lecturer in Biomedical Image Analysis at City, University of London. Huge Matlab fan, wrote the book "Biomedical Image Analysis Recipes in MATLAB: For Life Scientists and Engineers" published by Wiley-Blackwell.

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Error of the following code : "Array indices must be positive integers or logical values."
Not very clear, what are length_ijk and index_ijk? in the files you have added, miu has 262144 values, ind has 77 and freq has 6...

16 days ago | 0

Not able to write the image by reading xcel files generated , getting error of data type as shown in picture attached. Anybody please help.
This is not very clear, it would be better to copy the code instead of figures and provide a sample file so that the case can be...

16 days ago | 0

How to add colormap on an image?
I guess that this is a 2 step question, you want to add a colormap and then export as a png or jpeg, try the following, read an ...

1 month ago | 0

What is a good performance metric for pixels classification tasks
One good metric is the Jaccard Index, or the Intersection over Union. What this metric does is to divide true positives over th...

1 month ago | 0

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Does anyone know how to create graphics of the same size?
Hello You can use the command "print" https://uk.mathworks.com/help/matlab/ref/print.html?searchHighlight=print&s_tid=srcht...

1 month ago | 0

double data type in image processing
Another easy way around this is to divide the doubles by 255 X=imread('cameraman.tif'); %read the cameraman image X=doubl...

3 months ago | 1

Random shuffle of vector elements
This can be easily done by addressing the vector correctly. First you need a random order to shuffle your elements. You can do t...

4 months ago | 1

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how can i use a Gaussian gradient routine for remove the out of focused section in image processing
You could refine your processing using bwlabel to assign unique labels to the regions you have already detected. Then use region...

4 months ago | 0

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A ’BGR’ image.
Hello: First, changing channels is very simple you just need to change the third dimension of the image, e.g. image1=imread('p...

4 months ago | 1

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I cannot save matlab editor, the .m file.
I guess that you must have used some special characters like accents, have you copy-pasted something into the editor?

5 months ago | 0

Detecting a stain in a texture

5 months ago | 0

I need to find the phase of the images.
Hello The image that you show could be that of a phase, but it is hard to judge from what you are showing. In any case, here is...

6 months ago | 1

unshow unnecessary intervalls in a histogramm
Hello: What you need to do is rather simple if you capture the values of your histogram, instead of using hist to display dir...

6 months ago | 0

Mean computaion in matlab
If your data is in a matrix of dimensions [samples x 3], e.g. data=[lon1 lat1 value1; lon2 lat2 value2; lon3 lat3 value3; ...

6 months ago | 0

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convolution of 2 signals
You are confusing functions. conv is used to obtain the convolution, subplot is used to divide a figure and then plot inside eac...

6 months ago | 0

Compute convolution y[n]=x[n]*h[n]: x[n]={2,0,1,-1,3}; h[n]={1,2,0,1}

6 months ago | 0

How can I extract the GLCM features from each nucleus of mircroscope blood smear image?
One way to do this would be to crop each region, once you have found each object, you can use regionprops to determine the extre...

7 months ago | 0

How to Loop to plot histogram and line plot?
The following is not clear and most probably your error: for i=4:8;k=1:2 subplot(1,2,k) plot(Temp(:,3),Temp(:...

8 months ago | 0

fprintf or fwrite non ASCII characters
Have you tried using TeX formatting? I.e. \alpha \sigma \mu https://uk.mathworks.com/help/matlab/creating_plots/greek-letters...

8 months ago | 0

Labelling of x axis
There are 2 ways to solve this: First is to plot in the actual hours instead of the points of the matrix that is holding th...

8 months ago | 0

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how to change the plot background?
Most probably the first figure you are showing is and RGB (type "whos" and look for the dimensions it should be rows x columns x...

9 months ago | 0

Plotting Several 2D Spatial Cross-section Data in 3D (GPR Data)
In terms of functions you can use mesh, surf, isosurface, isocaps and others. But what is more important is what you are trying ...

9 months ago | 0

How to make a bar graph using user input values
Several errors, First, clear your figure every time you play otherwise they will overlap (use clf). Second, you are always...

9 months ago | 0

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how to change the type of binarize threshold
I agree with the previous comments, the first T is not a table. So two comments 1) do not use T for a value first and then fo...

9 months ago | 1

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¿Porque no corre mi código? No aparece nada
Hola, Primero unas recomendaciones: 1) te recomiendo escribir en ingles porque en espan~ol es mas dificil tener ayuda 2) te r...

9 months ago | 0

title according to the file name
Perhaps you want to add values to the titles of your figures, try something like this for k=1:9 subplot(3,3,k) title(...

9 months ago | 1

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Plot {(x,y,z)| x²+y²<1, 0<z<x+2}
It depends on what you want. One way to code this would be to define your space, i.e. the range of each of each variable, say x ...

11 months ago | 0

How can I get rid of the gap on the x-axis?
How about axis tight would that work?

12 months ago | 0

How to put separate titles above multiple pcolor subplots
The issue is that you are setting the axis to off with this set(gca,'visible','off'); Your problem will be solved if you use ...

12 months ago | 0

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