Homework-11
Question 1
The following is a picture of a 3D box.
1
Identify 3 vanishing points and mark them (on the page) as (u1, v1), (u2, v2), (u3, v3).
2
Without knowing anything about the camera constant f, is it possible that the principal point is at the
point that you have chosen for (u1, v1)? Explain your answer.
Answer
Yes / No / Impossible to tell
Because:
3
If it is known that the camera constant is f = 10, the camera location is at u = 10, v = 10, and the location
of (u2, v2) in the image is u2 = 5, v2 = 30, compute the 3D direction of the parallel 3D lines that meet at
that vanishing point.
Answer:
Question 2
You are given the following information about a famous tennis player: His height is 210 cm, his legs are
90 cm. long, and the length of his face is 30 cm. The following diagram illustrates these measurements:
| |
height
legs face
Measurements were taken from pictures of 5 tennis players. The pictures are distorted by perspective
projection:
t1 height is 6 cm, legs are 2.2 cm. long, and length of face is 2 cm.
t2 height is 7 cm, legs are 2 cm. long, and length of face is 2 cm.
t3 height is 10 cm, legs are 2 cm. long, and length of face is 1 cm.
t4 height is 4.2 cm, legs are 1 cm. long, and length of face is 1.2 cm.
t5 height is 17 cm, legs are 9 cm. long, and length of face is 4 cm.
a. Which picture (from t1,t2,t3,t4, t5) is more likely to be the tennis player than all the others?
Answer: t1 t2 t3 t4 t5
b. Which picture (from t1,t2,t3,t4, t5) is the second most likely to be the tennis player?
Answer: t1 t2 t3 t4 t5
