whereswaldo
A toy example revisiting the same approaches I tried as an undergrad in 2007. Really. I did this in like seven cumulative hours, was pretty fun.
See Main.kt for notes, ModelTestCases for various failed attempts at finding Waldo, Model/ModelComponent for a vision of the future, and WaldoHistogramFinder to see my quick conversion of my 2007 C++ method into quick and dirty Kotlin.
I'm sorry to disappoint you, but this doesn't reliably find Waldo. There are definitely one-stop libraries that will for you.