Matlab & Simulink Coder: Using a polygon shaped ROI to mask an input image

Hi Everyone,

I am trying to use Simulink to take a greyscale image and mask a region of interest (polygonal). My goal is to use these values as input for for my control system. The code should be exported with Simulink Coder to a RT system afterwards.

My first idea was to use the Computer Vision Toolbox but I can't come up with an appropriate function here. My second try was to use a MATLAB function and use poly2mask() to extract the region of interest, but it's obviously not supported for Code Generation.

Any ideas how I could approach my problem next?

Thanks,

Lars

Answer 1

[Lars]

In the meantime I came up with the following code

function extractedTemps  = extractPolygon(tempImage, vertices) %#codegen
% Inputs: Image & vertices(x, y)

% Get image size
[iY, iX] = size(tempImage);

% Coordinates to all pixel
[x, y] = meshgrid(1:iX, 1:iY);

% Check if in polygon
[in] = inpolygon(x,y, vertices(1,:), vertices(2,:));

% Extract Temperatures
coder.varsize('extractedTemps',[21504 1]);
extractedTemps = tempImage(sub2ind(size(tempImage),y(in), x(in)));

Unfortunately diagnostics still gives me the follow error:

Saturate on overflow detected. In MATLAB Function 'ExtractPolygon': function extractedTemps = extractPolygon(tempImage, vertices) %#codegen

Any idea whats happening here?