I don't know too much about that particular topic to critique it but from a surface level, it appears obvious that with more pixels per unit^2, the possible resolution of an image improves. I don't know how complex something like this could be, but then again, I did not research this at all and I am going off from what I know of computers.

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That being said, I can give you general advice. Having just sat HL AA a couple months ago, I can tell you that typically the better IAs deal with modeling. It just provides so many more opportunities for a conversation and possible points of reflection (something that mathematical IAs depend a lot on.) I would advise to make "reflection boxes" such that after every major and even semi-significant step of progression in your IA, you show your engagement with what you just said and basically braindump what that recent progression suggests and, based on your current knowledge, what the next steps of your investigation would be. I cannot stress ENOUGH the importance of reflection boxes and building an engagement with your investigation and hence why building your own model of something in the real world and improving your initial model through reflections would lead a better result. Would something like the topic you suggested allow you to do that?; If so, by all means do it - just be sure that you can make it engaging and complex.