I don't think we are talking about the same thing...

This looks cool, but it's not what I was looking for. I want my computer to "look" at my drone and control it from the outside (like a human operator).

You would still want an on board flight controller to handle the primary flight controls. That is, the system that keeps it level and in the air, or pitched at a given angle moving at a set flight speed and elevation. That stuff needs to be internal to the craft to be reliable. From there you can have the drone take external high level input.

Think of it as a high and low level system pairing. The high level system can do things like decide "Go over there", or "Raise altitude to X", while the low level system breaks down the higher level commands into the different engine rotational speeds needed to achieve the high level goals, and be able to correct for issues like being bumped around by a slight breeze. The lower level system should also ideally be able to do some of its own thinking, such as "I've lost contact with the base station computer, return to home base or settle and land where I am" kind of thing.

Trying to do quad copters without onboard flight controller systems is a road of frustration and pain.

What Luckless said.

And to expand a bit on it:

You always have the flight controller, also in a normal radio controlled drone, it's not possible to fly it without one.

The system for a normal RC drone would look like this:

Human -> RC Transmitter ===over the air====> RC Receiver -> Flight Controller -> Speed Controller(s) -> Motor(s).

So if you want to fly it with an external computer (or phone) there are two roads:

- get or build an RC transmitter compatible with whatever radio standard the receiver in the drone uses (there are several from the different RC manufacturers), that can be controlled by a PC/Phone.

- Replace the receiver with something easier and cheaper to get/build a transmitter for (my suggestion)

You always have the flight controller, also in a normal radio controlled drone, it's not possible to fly it without one.
The system for a normal RC drone would look like this:
Human -> RC Transmitter ===over the air====> RC Receiver -> Flight Controller -> Speed Controller(s) -> Motor(s).

At the risk of hijacking the thread:

What I wanted to achieve was: To write a computer vision program which allows a PC with a pair of cameras to control an RC vehicle as well as a human with a set of eyes. While I did find the computer vision algorithms I was looking for, I ended up giving up, beause it seemed too hard to emulate the RC. I assumed [falsely] that it would be as easy as emulating a TV remote control. My main problem, was that I couldn't find any USB rc controller.