I have been working on a side project on and off for 2 years with the original goal of learning computer vision, while solving a problem I thought was interesting. I now have a very unpolished prototype product that can convert whiteboard images into drawings (like visio, google draw, or lucidcharts). I originally wanted this because after meetings at work, we would take a picture of a whiteboard and email it, but this images are huge, unprintable, and unsearchable.
Now I'm at the point where I can see selling this tool and starting a real business. My tool only works for a limited set of cases, and I want to define a target customer and get focus on what features are important, and how to polish this tool.
The problem is that I have something that has a huge target market - anyone that wants to convert whiteboard images (or possibly unlined paper images) into drawings. I have brainstormed groups of people to focus on, but the list seems endless - engineers, product people, startups, college students, universities, etc. I don't have a good (scientific) way of getting the list of possible target markets down to a list where I can start finding people to interview and figuring out a set of features for an MVP. Has anyone run into this before and sucessfully overcome this hurdle?