[roflmaostc]

Mathematically speaking the paper is correct.

I think it actually depends what you define as "pixel". Sure, the pixel on your screen emits light on a tiny square into space. And sure, a sensor pixel measures the intensity on a tiny square.

But let's say I calculate something like:

  # samples from 0, 0.1, ..., 1 
  x = range(0, 1, 11)
  # evaluate the sin function at each point
  y = sin.(x)

Then each pixel (or entry in the array) is not a tiny square. It represents the value of sin at this specific location. A real pixelated detector would have integrated sin from `y[u] = int_{u}^{u + 0.1} sin(x) dx` which is entirely different from the point wise evaluation before.

So for me that's the main difference to understand.