Calculating angle of perspective from a picture of a rectangle with known dimensions
Hello r/geometry! I took a picture of a rectangle that I know to be exactly twice as wide as it is tall. I took the picture at a very much not-head-on angle, and I would like to know the exact angle I took it at in three dimensions, relative to the rectangle itself. For example, if I had to guess, I was ~10 degrees above head-on, ~70 degrees to the right, and rotated ~5 degrees clockwise from the rectangle, but I'd like to be able to calculate those angles more confidently by taking apparent angle and side length measurements from the picture of the rectangle.
Is this possible? Is there a formula that I would be able to understand well enough to calculate my perspective from a bunch of pictures from different angles? I'm asking this as someone with a respectable math education mostly in statistics.