Your vision is always a singular dot in space, unless you have amblyopia or something else causing your eyes to point in different directions. Even if you’re looking at a featureless line, your eyes are fixed on a single point in space. It’s not like one eye is looking somewhere different from the other eye. The triangle still exists.
There is no difference to stereo vision depth perception regardless of how the view points are oriented in the X and Y axis. The practical proof for this is in rangefinders; neither simple consumer stereo rangefinders nor complicated military stereo rangefinders, such as those found on battleships
or antiaircraft guns, are oriented in the Y axis to gain some advantage. There’s no need. The triangle is the same regardless of X-Y orientation.
I see what you’re saying about the example of two completely featureless lines oriented exactly along the X axis in a completely featureless space, as this wouldn’t work with a coincidence rangefinder, but this is an edge case and not something you’d encounter in real life. You’d also have other cues for depth perception beyond just stereopsis.
It’s not that the triangle doesn’t exist, but that the brain has multiple options for forming said triangle, only one of which is real. Threw the following together to illustrate:
I was looking at a grid lattice wall paneling just this week which had the same effect.
If the pattern is perfectly uniform, the eyes can’t distinguish between different features in it. The whole situation is a bit comparable to a stereoscope. Shifting the eyes out of plane with the pattern causes the false images to split vertically while the one true image remains. This isn’t an issue most of the time, but it does demonstrate how some situations invalid for stareopsis can be tackled with a simple head tilt.
Rangefinders aren’t usually looking at patterns in walls for example. Aircraft or ships don’t create uniform enough patterns. Yes it’s still an edge case, but I just wanted to explain my point that tilting the head does offer the brain more to work with, which in some confusing situations can be the critical to correctly perceiving the situation.
Your vision is always a singular dot in space, unless you have amblyopia or something else causing your eyes to point in different directions. Even if you’re looking at a featureless line, your eyes are fixed on a single point in space. It’s not like one eye is looking somewhere different from the other eye. The triangle still exists.
There is no difference to stereo vision depth perception regardless of how the view points are oriented in the X and Y axis. The practical proof for this is in rangefinders; neither simple consumer stereo rangefinders nor complicated military stereo rangefinders, such as those found on battleships or antiaircraft guns, are oriented in the Y axis to gain some advantage. There’s no need. The triangle is the same regardless of X-Y orientation.
I see what you’re saying about the example of two completely featureless lines oriented exactly along the X axis in a completely featureless space, as this wouldn’t work with a coincidence rangefinder, but this is an edge case and not something you’d encounter in real life. You’d also have other cues for depth perception beyond just stereopsis.
It’s not that the triangle doesn’t exist, but that the brain has multiple options for forming said triangle, only one of which is real. Threw the following together to illustrate:
I was looking at a grid lattice wall paneling just this week which had the same effect. If the pattern is perfectly uniform, the eyes can’t distinguish between different features in it. The whole situation is a bit comparable to a stereoscope. Shifting the eyes out of plane with the pattern causes the false images to split vertically while the one true image remains. This isn’t an issue most of the time, but it does demonstrate how some situations invalid for stareopsis can be tackled with a simple head tilt.
Rangefinders aren’t usually looking at patterns in walls for example. Aircraft or ships don’t create uniform enough patterns. Yes it’s still an edge case, but I just wanted to explain my point that tilting the head does offer the brain more to work with, which in some confusing situations can be the critical to correctly perceiving the situation.