What should be the strategy to use machine learning in order to improve the accuracy of a system that measures some aspects from an image using Computer vision ?

I have developed a system on MATLAB to measure some aspects of Human Body using computer vision for my research. The problem with it right now is that it is accurately providing results for only some people in my dataset and now that the basic framework of the project is developed I need to work on improving its accuracy. Will machine learning be helpful to be used in the next stage? If yes how, I mean what should be the strategy? Or if anyone can suggest some other technique or algorithm that can be implemented to improve the accuracy of the system.