A look at the split-second decisions that can change a everyday event into a disaster.

Close Calls: On Camera - Netflix

Type: Documentary

Languages: English

Status: Running

Runtime: 30 minutes

Premier: 2014-10-20

Close Calls: On Camera - Camera resectioning - Netflix

Camera resectioning is the process of estimating the parameters of a pinhole camera model approximating the camera that produced a given photograph or video. Usually, the pinhole camera parameters are represented in a 3 × 4 matrix called the camera matrix. This process is often called camera calibration, while it can also mean photometric camera calibration.

Close Calls: On Camera - Extrinsic parameters - Netflix

R        ,        T              {\displaystyle R,T}   are the extrinsic parameters which denote the coordinate system transformations from 3D world coordinates to 3D camera coordinates. Equivalently, the extrinsic parameters define the position of the camera center and the camera's heading in world coordinates.                     T              {\displaystyle T}   is the position of the origin of the world coordinate system expressed in coordinates of the camera-centered coordinate system.                     T              {\displaystyle T}   is often mistakenly considered the position of the camera. The position,                     C              {\displaystyle C}  , of the camera expressed in world coordinates is                     C        =        −                  R                      −            1                          T        =        −                  R                      T                          T              {\displaystyle C=-R^{-1}T=-R^{T}T}   (since                     R              {\displaystyle R}   is a rotation matrix).

Camera calibration is often used as an early stage in computer vision. When a camera is used, light from the environment is focused on an image plane and captured. This process reduces the dimensions of the data taken in by the camera from three to two (light from a 3D scene is stored on a 2D image). Each pixel on the image plane therefore corresponds to a shaft of light from the original scene. Camera resectioning determines which incoming light is associated with each pixel on the resulting image. In an ideal pinhole camera, a simple projection matrix is enough to do this. With more complex camera systems, errors resulting from misaligned lenses and deformations in their structures can result in more complex distortions in the final image. The camera projection matrix is derived from the intrinsic and extrinsic parameters of the camera, and is often represented by the series of transformations; e.g., a matrix of camera intrinsic parameters, a 3 × 3 rotation matrix, and a translation vector. The camera projection matrix can be used to associate points in a camera's image space with locations in 3D world space. Camera resectioning is often used in the application of stereo vision where the camera projection matrices of two cameras are used to calculate the 3D world coordinates of a point viewed by both cameras. Some people call this camera calibration, but many restrict the term camera calibration for the estimation of internal or intrinsic parameters only.

Close Calls: On Camera - References - Netflix