How to replace Nonscalar struct for Matlab Coder error?

2 views (last 30 days)
When I'm trying to transform my Matlab code to C, this error appeared yet I don't know how to modify it as it necessary in my function.
%% Remove small objects.
binaryImage = imclearborder(binaryImage);
binaryImage = bwareaopen(binaryImage, 100);
%% Invert the binarized image
% binaryImage = ~ binaryImage;
%% Get centroid on image
stats = regionprops(binaryImage, 'Centroid'); % acting on the cleaned image
centroids = cat(1, stats.Centroid);
x1 = centroids(1,1);
y1 = centroids(1,2);
x3 = centroids(3,1);
y3 = centroids(3,2);
The error " Directly accessing field or property of nonscalar struct or object not supported for code generation" showed at
centroids = cat(1, stats.Centroid);
How I can resolved it as it is necessary for my function.

Accepted Answer

David Fink
David Fink on 8 May 2020
centroids = cat(1, stats.Centroid);
is just concatenating the centroid row vectors in the first dimension (vertical), which can be replaced by a loop:
numRegions = numel(stats);
centroids = zeros(numRegions, numel(stats(1).Centroid)); % pre-initialize to set size
for region = 1:numRegions
centroids(region, :) = stats(region).Centroid; % write one row at a time
We are looking to allow the original syntax in a future release of MATLAB Coder!
WanYu on 10 May 2020
Hi David,
This error came out after that,
The invoked code did not call entry-point function
What should I do or how to resolve this error?
David Fink
David Fink on 11 May 2020
It looks like the test code that calls the entry-point errored out - "View errors" should give the specifics.

Sign in to comment.

More Answers (0)


Find more on MATLAB Coder in Help Center and File Exchange




Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!