## ← 16-09 Perspective Projection

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Unit 16 09 Perspective Projection.mp4

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Showing Revision 1 created 11/28/2012 by Amara Bot.

1. [Thrun] So we just learned something really important,
2. which is the central law of perspective projection,
3. which basically says that in a pinhole camera, or in fact any camera,
4. the projective size of any object scales with distance.
5. So you have an object that's yea tall over here
6. that looks just about the same as an object yea tall over here.
7. In math x is proportional to the size of the object
8. but inverse proportional to the distance to the object,
9. and the only constant that then governs that relationship is the focal length, f.
10. So if we take an object and move it further away,
11. it'll appear smaller, and we all know this.
12. Just look at this object over here, how large it is.
13. And as I move it away from the camera, it becomes smaller.
14. Large...and small.
15. And that's a function of distance.
16. The law that governs the size change of this object in appearance
17. relative to the camera image is the perspective law we just saw.