Measure the surface of trapezium image

Hello, does anyone know how I can measure the surface/area of images of trapezoidal shape in matlab? Thank you

Answer 1

[Image Analyst]

Try polyarea(). If that doesn't work for you, then explain your situation better.

[Emmanuella al]

I also thought of polyarea() but because Im new to matlab I don't know how to make polyarea() work for an image. What I mean!, I have for example an image that is saved in .png format and the shape of it is trapezium. I don't know the dimensions of the image (Base a, Base b, height). I can find them but my result I'd like to be the matlab to measure that dimensions and then calculate the surface area of it each time for my images. Thank you in advance

[Image Analyst]

If you don't have coordinates, then segment the region and use regionprops() and ask for Area. See my Image Segmentation Tutorial: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862