I would be grateful to receive some example of usage of builtin function 'regionprops'

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Maura E. Monville 2019-7-18

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评论： Maura E. Monville 2019-7-19

采纳的回答： Matt J

Dear MatLab Experts,

I would greatly appreciate your help at understanding how to use the output of builtin function 'regionprops'

My understanding is that it would output a scalar value for each selected property for each connected component.

I have a set of closed curves that I convert to binary masks. The attached zipped archive contains some of such curves.

Each closed curve is descrived by the ordered coordinates in a text file.

Each curve contain only one connected component.

However, when i call 'regionprops' I get a vector of values for each feature I selected.

For instance, how can I have 255 'Area' values and 255 centroid coordinate pairs?

I have attached my script 'Get-Collimator_Features.m' that calls builtin function 'regionprops'.

How can I reduce a vector to a single scalar value, for instance for the Area, etc...?

Some correct usage examples of 'regionprops' would be very appreciated.

Thank you very much.

Best regards,

maura

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Matt J 2019-7-18

The code you've attached returns an error. Since the only important line is,

   stats = regionprops('table',BW,'Area','FilledArea','ConvexArea','Centroid',...
                                  'Circularity','Eccentricity','EquivDiameter',...
                                  'MaxFeretProperties','MinFeretProperties','Orientation');

it would be better/simpler if you just attach BW in a .mat file so that we can test just that specific line of code.

Matt J 2019-7-19

BWCurve.mat

Maura's data file moved here.

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Answer 1

Matt J 2019-7-19

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https://ww2.mathworks.cn/matlabcentral/answers/472333-i-would-be-grateful-to-receive-some-example-of-usage-of-builtin-function-regionprops#answer_383979

Because I don't have R2019b, I had to run a somewhat modified version of the code

S=load('BWCurve.mat','CBW');
BW=S.CBW;
% Get Area Features 
   stats = regionprops('table',BW,'Area','FilledArea','ConvexArea','Centroid',...
                                  'Eccentricity','EquivDiameter',...
                                  'Orientation');

The result is

stats =
  1×7 table
       Area           Centroid        Eccentricity    Orientation    ConvexArea    FilledArea    EquivDiameter
    __________    ________________    ____________    ___________    __________    __________    _____________
    6.6497e+05    558.43    433.81      0.68914         -3.9677      1.0211e+06    1.0211e+06       920.15   

This looks fine to me. I'm not sure what "vectors" you are referring to. Nevertheless, if you want to extract the 'Area" data from the table and put it in a separate numeric variable, you would do

Area=stats{:,'Area'}