I spent two weeks building a computer vision component to estimate how full a plastic
container is from drone imagery. Translucent white containers, whitish chemical product
inside, shot obliquely from a drone during field inspections.
The headline number looked good: mean absolute error of 0.055 on fill fraction, Pearson
correlation of 0.97. Then I audited my own evaluation and found that 38 of my 46 test






