The browser demo page says "Dextro supports up to 4 objects to be detected concurrently when used via the full API.", I think that's the problem.

Hey tunnuz and limejuice, sorry to hear we only picked up on 4 of the planes. We've biased our service towards precision rather than recall; thus, we try to be wrong about detected objects as little of the time as possible at the expense of perhaps missing a few object instances.

I want to clarify: the 4 object concurrent detection refers to 4 classes of objects. On the Experiment page, you can only choose one class to detect on (whether that is person, bottles, cars, etc). However, by using the API, you can simultaneously search for cars, planes, people, and motorcycles, for example.

Ok, so the two 4s have nothing to do with each other. Thanks for the clarification.