Long-time blog readers (such as there might be) will remember that I gave up on American football about 10 years ago. Back then, my kids were young enough that what they were interested in was really just a subset of what I was interested in. But now they're older, and they have their own interests. My third kid, Jerome Jerome the Metronome, is into American football, so now it's a thing that gets watched at my house again.
He and his older brother, Articulate Joe, both hate the process of spotting the ball. I agree that it's pretty ridiculous to bring out a chain that is EXACTLY 10 yards long when the ball is resting wherever some old dude thought he saw it last. This got me thinking about why football doesn't have a technological answer to the problem. Something like soccer goal-line technology.
My understanding of goal-line technology is that there is a sensor in the middle of the soccer ball, and when the sensor is beyond the line by the radius of the ball, it knows the entire ball is beyond the line and signals a goal. That works great for a spherical ball, but footballs are oblong. So any sensor in the middle of a football would need to know its orientation to the ground as well. So if the sensor is pointing at the line along the ball's long axis, it knows it has to be farther away from the goal-line because the pointy end sticks out more. But all that math is perfectly solvable; you tell me the vector of the football's main axis and I can tell you (theoretically, since I've forgotten most of my vector calculus class) the distance from the middle of the ball to a vertical plane tangent to the surface of the ball. Boom, no more touchdown reviews that end up wrong (like in the BYU-Hawaii bowl game last month). And this tech can also be used to spot the ball on EVERY PLAY. Imagine that running underneath the hash marks were a series of LED lights, and they were synced with the video feed (like how cricket reviews of leg-before-wicket are synced). All that's needed to know the EXACT spot of the ball is to mark on the video feed the moment the runner is judged to be down. The LED corresponding to the correct placement lights up, the referee places the ball there, and on we go.
Is that an expensive solution? Probably. This isn't for every Pop Warner field in the country. But it seems to me the NFL makes enough money to get this going in the 30 stadia they use.
Perfect touchdown reviews, and perfect spotting, is technologically possible. If the NFL isn't using it, it's because they don't care to get it right.