3D重构基础七－－structure and motion

structure＝structure of the scene; 

motion = motion of camera.

Overview of the projective structure and motion algorithm.

上述方法只是general，有可能出现ambiguity，比如：

Left: Illustration of the four-parameter ambiguity between two projective reconstructions sharing a common plane. If the base of the cube is shared, a projective transformation can still affect the height of the cube and the position of the third vanishing point. （这种情况下，投射可以影响立方体的位置和形状）

Right: A fundamental problem for many (man-made) scenes is that it is not possible to see A,B and C at the same time and therefore when moving from position 1 to position 3 the planar ambiguity problem will be encountered.（从位置1到位置3不可能总是同时看到点A、B、C）

因此，引入更实际的方法来做recovering the 3D structure and camera motion。

补充定义：1、右零空间

待续。