Another app idea that I’m never going to make so someone else can have it. Grid size is really hard to get right for home coffee nerds. If you’ve got a 250g bag of something expensive, you can’t run half of it through the grinder to get the grind right. This is an especially big problem if you are running different brew techniques¹.

The factors everyone cares about are particle size and consistency. How big are the chunks, and how much do those sizes vary?

Modern smartphone cameras are amazingly high resolution. This photo is a crop out of the middle of a picture from my Nexus 6p on 5mm squared paper. At my screen resolution each square is about 25mm, so that’s plenty of magnification.

The question is:

Can modern smartphone cameras + computer vision + some graph paper² measure particle size usefully well?

Here’s an enlarged square, bigger than 100%:

I have no idea if there is enough contrast in the images for the CV algorithm to see grain boundaries. Maybe that’s not even required, perhaps you can just do blob detection on the smallest particles?

Seems like a pretty straight middle section, and maybe you could just discard anything really big as likely to be a clump?

Anyway, let me know if you are a CV genius and you make this app, I’d use it.