Does listing several research directions in SOP give the impression that I have a shallow research interest? I am applying to MS in CS degree. In my SOP I wish to talk about four distinct, non-overlapping research directions. Two of these pertain to computer vision and the other two pertain to machine learning. (I am interested in how computer vision utilizes the theory of machine learning.)

Now my question is, if I talk about all four of these distinct, non-overlapping research directions and quote a paper each in these 4 directions, will it give the impression that I have a shallow superficial research interest? Also I don't have any particular research idea in my mind for any of these directions yet.

As I am still in college, I don't get enough time to conduct research on these directions. My college coursework keeps me busy for most of the time. So as of for now I can't narrow down to one of these directions.

Over the course of the last four years, I read papers whenever I got time and I saw a pattern in all these papers. I realized that the papers I read fall into these distinct directions. I realized how one paper builds on top of the other. It's just that I was casually reading this stuff not with an intention to contribute to either of these directions. But if you ask me to write a grad level thesis I would definitely choose one of these four directions.

Edit: The papers are pivotal papers to those directions. None of them are older than 2012 and they have established that direction. So omitting them could potentially jeopardize the coherence of my SOP.
As I read your question, it seems to me that you have one area of interest: Machine learning applied to computer vision.  Consider revising to emphasize that.

You mention quoting papers.  Unless they're papers you wrote, consider leaving that out.  Admissions committees want to know your interests and accomplishments.