To apply three different camera models in different situations.
Today, we are talking about models in camera. As we all know, there are a lot of lens in different position to change the road of light, and it’s so important to carefully calculate their distance as well as shape. Let’s pay more attention to several basic models about camera.
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1.Perspective Projection
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2.Affine Projection
3.Orthographic projection
When it is a prior known that the camera always remains at a roughly constant distance from the scene, we can go further and normalize the image.
When it is a prior known that the camera always remains at a roughly constant distance from the scene, we can further normalize the image coordinates, so that m=-1.
All light rays parallel to the k axis and orthogonal to the image plane ’.
Therefore, the metric is well preserved in the image.
There is a picture to describe the theory of camera clearly.
In reality, the perspective equation is only valid when all distances are measured in the camera’s reference frame, and image coordinates have their own origin.
In practice, the world and camera coordinate systems are related by a set of parameters.
Intrinsic parameters relates the camera’s coordinate system to the image pixel coordinate system.
Extrinsic parameters relate the camera’s coordinate system to a fixed world coordinate system and specify its position and orientation in space.
A process to estimate intrinsic & extrinsic parameters is known as geometric camera calibration.
That’s all, thank you for watching~