Actual dimensions from image in matlab gui

How do i obtain actual dimensions of an object from its image in matlab gui for R2015a

Answer 1

[Walter Roberson]

https://www.mathworks.com/matlabcentral/answers/387668-how-to-measure-the-real-size-of-an-object-from-an-unknown-picture#answer_309549

https://www.mathworks.com/matlabcentral/answers/18380-getting-x-and-y-for-3d

https://www.mathworks.com/matlabcentral/answers/55569-is-this-formula-correct