Depth Perception
Depth Perception
Depth Perception
TECH) 12ECP007
Lens Distortions
Radial distortions arise as a result of the shape of lens, whereas Tangential distortions arise from the assembly process of the camera as a whole. This distortion is due to manufacturing defects resulting from the lens not being exactly parallel to the imaging plane
Camera Calibration
Camera calibration gives us both a model of the cameras geometry and a distortion model of the lens. These two informational models define the intrinsic parameters of the camera. Here well learn how to describe the intrinsic and distortion properties of a camera.
A rotation is equivalent to introducing a new description of a points location in a different coordinate system. Rotating the coordinate system by an angle is equivalent to counter rotating our target point around the origin of that coordinate system by the same angle .
The representation of a two-dimensional rotation as matrix multiplication is shown already in the figure. If we rotate around the x-, y-, and z-axes in sequence with respective rotation angles , , and , the result is a total rotation matrix R that is given by the product of the three matrices Rx(), Ry(), and Rz(), where
To shift from a coordinate system centered on an object to one centered at the camera, the appropriate translation vector is simply T = originobject origincamera.
Chessboards
The calibration object used in OpenCV is a flat grid of alternating black and white squares that is usually called a chessboard In principle, any appropriately characterized object could be used as a calibration object, yet the practical choice is a regular pattern such as a chessboard or a box covered with markers.
References
Book Learning OpenCV by Gary Bradski and Adrian Kaehler Paper of Stereoscopic vision for depth perception by Luis Copertari published in august 2007,volume 3 Paper of Depth Estimation using Monocular and Stereo Cues by Ashutosh Saxena, Jamie Schulte and Andrew Y. Ng.