I want to insert rectangle shape to the real time image

MATLAB Function3:

function fakeImg = fcn(RealImg)

I = RealImg;

fakeImg = insertShape(I,"line",[10 10 40 40],Color="black",Opacity=1);

Answer 1

[Image Analyst]

You might find using rectangle to draw into the overlay is faster than using insertShape to burn the rectangle into an RGB image.

Answer 2

[Birju Patel]

You can also use the Draw Shapes block in Simulink:

https://www.mathworks.com/help/vision/ref/drawshapes.html