quartz/content/notes/10-3d-Cameras.md

title	tags
10-3d-Cameras	lecture cosc342

CAMERAS AND PROJECTIONS

• Cameras project the 3D world onto a 2D image
  • Input is 3D points: (𝑥, 𝑦, 𝑧)
  • Output is 2D points: (𝑢, 𝑣)
  • What form should P have?

[!INFO] need to apply a transformation to convert 3d coords to 2d coords P should be a 3 row and 4 column matrix

WHICH CUBE LOOKS RIGHT?

[!INFO] each cube is a projection of 3d points onto 2d space. middle cube is perspective transformation left is isometric right is orthographic

ORTHOGRAPHIC PROJECTION

• Simple way to go from 3D to 2D
• Delete one dimension!
• Deleting X projects to the X -Y plane
• This is not how our eyes work

[!INFO] z coordinate is removed since the third column is zero

PERSPECTIVE PROJECTION

• Our view of the world:
  • Distant objects looks smaller
  • Parallel lines in 3D converge in 2D
• The pinhole camera
  • A simple, but useful, model
  • There is a central point of projection (the pinhole, often a lens in reality)
  • Light travels from the world, through the pinhole, to the image plane