一个编程人员与机器人的对话

智能机器人理论基础对人类来说，90%的信息来自于视觉。就算对一个只有3岁的小孩，也很容易识别一个物体是否苹果。但是对机器人来说，视觉是否是一个很简单的问题呢？

如下是一个编程人员与一个机器人的对话。

Programmer: I want you to tell me if you see any apples.

Robot: Describe this thing you call "apple."

Apples are apple-shaped. Look for something that's apple-shaped.

What do you mean by "apple-shaped"?

Well, sort-of round with a dimple at the top and a little stem.

This "stem" is always at the top of an apple?

Not necessarily. The apple might be upside-down or sideways. You must look for stems in all directions.

What if the stem is hidden behind the apple so I can't see it? And what is a stem anyway?

Good point. Forget about stems. Let's start with color. Most apples are red, but then again some are green. I guess a bad apple might even be brown.

Are all things red, green or brown apples?

No! Apples are other things too. For example, most apples are a little bit shiny.

What do you mean by shiny, and how shiny is "a little bit shiny"?

They reflect light well, but not as well as a mirror.

Great. What is a mirror? And what do you mean by "reflect"?

A mirror is something that shows an image of you and what's behind you when you look into it.

I don't know what I look like, or what's behind me - I only have one camera.

Ok, forget about the mirror. You asked what "reflecting" means. Reflecting is when light bounces off of something. If there's a bright light on the apple, you will see a small white reflection off of it.

Got it. So wherever I can find red, green, or brown, and a white spot inside (if it's bright), there's an apple. How can I tell if the light is bright enough that it would make a reflection?

Argh! Never mind! Let's try something else - size. Apples are about 3 inches across.

What do you mean by "about"? If it's 4 inches across could it be an apple? How about if it's 27 inches across?

Let's say all apples are between 3 and 5 inches across.

Is a quarter of an apple still an apple?

Yes, but let's pretend it's not.

What if in front of me there's a red apple sitting on a red table? How can I tell where the apple ends and the table begins? If I can't do that, I couldn't possibly find an apple.

Well, you can see the edge of the apple, right?

Maybe. How do I do that?

The edge is darker than the rest of the apple if there's a shadow, or lighter if there's no shadow and the table is lighter than the edge of the apple, but the apple isn't necessarily a perfectly solid color - I mean there could be dark spots on the apple that aren't edges, and - oh no - there could be photographs of apples on the table which aren't actually apples, or even a wax model of an apple which looks exactly like an apple but isn't, or the apple could have a bite taken out of it, or be really far away so it looks too tiny or too close so it looks really big, or, or... um...

Had enough?

Yes, I think I get your point.