I was reading about optimization for an ill-posed problem in computer vision and came across the explanation below about optimization on Wikipedia. What I don't understand is, why do they call this optimization "***Energy minimization***" in Computer Vision?

> An optimization problem can be represented in the following way:
> 
> Given: a function $f: A \to R$ from some set $A$ to the real numbers
>
> Sought: an element $x_0$ in $A$ such that $f(x_0) ≤ f(x)$ for all $x$ in $A$
> ("minimization") or such that $f(x_0) ≥ f(x)$ for all $x$ in $A$
> ("maximization"). 
>
> Such a formulation is called an optimization problem
> or a mathematical programming problem (a term not directly related to
> computer programming, but still in use for example in linear
> programming – see History below). Many real-world and theoretical
> problems may be modeled in this general framework. **Problems formulated
> using this technique in the fields of physics and computer vision may
> refer to the technique as energy minimization, speaking of the value
> of the function $f$ as representing the energy of the system being
> modeled.**