tutorial on integral image

[johnnychen94]

I believe we need an IntegralArrays version of https://juliaimages.org/stable/examples/color_channels/indexed_image/#demo_indexed_image

[timholy]

That's an IndirectArray tutorial, not an IntegralArray tutorial. I don't see any tutorials that use the (soon to be deprecated) integral_image, am I missing something?

[johnnychen94]

Oh sorry for the inaccuracies. I notice the examples in https://github.com/JuliaImages/IntegralArrays.jl is pretty thin, I think we need a more insightful explanation on why we need this type (e.g., performance), and how it is used in image processing just like the IndirectArray demo.

[timholy]

Yeah, it's not a widely used type (so far, anyway). I once knew applications that needed it, but I kind of forget them now. Looks like https://www.codeproject.com/Articles/441226/Haar-feature-Object-Detection-in-Csharp has a practical use-case. (This was something that the very first GSoC student was interested in.)

[johnnychen94]

JuliaImages/ImageFiltering.jl#241 is a good use case; we can also use this as a demo.