Linear Calibration (from a geometry)
Linear Calibration calibrates a camera so a real world
coordinate system may be used instead of image pixels.
Typically this
tool is used in two modes:
In calibration mode:
The calibration is performed by looking at an object of known size. This calibration
is saved to file.
In run mode:
The calibration is loaded and attached to the current image in the
Image viewer. When using a calibration, load the calibration that was
previously saved.
Saving the sequence or workspace will save this
calibration data.
Defining a Calibration Manually
Under the image
calibration properties input the scale factors.
The scale factor for x and y
Scale X mm/pixel
Scale Y mm/pixel
The desired world origin
World Origin X
World
Origin Y
The pixel location for the world origin
Pixel Origin X
Pixel Origin Y
Defining a 2D Camera perspective calibration by
looking at an object of known size
Looking at a rectangle
Not implemented to date
Looking at a circle/ellipse
Input is an ellipse or a set of points that define a circle. Under the
grid settings (geogrid tab) set the grid properties as follows:
Grid Size:
X Dimension = 2
Y Dimension = 2
Z Dimension (if available) = 1
Spacing: Set to the ellipse diameter in x and y
On
the Geometric tab set the "Calibration/Run method to "Input
points = ellipse". Ensure that the points that define the ellips
(usually the prevoius step in the program) have been defined. Hitting
the
set button will create the calibration. This can now be saved. Notice
that when the calibration has been created the following properties
reflect the calibration data: Scale X mm/pixel
Scale Y mm/pixel
The scale factor for x and y.
World
Origin X
World Origin Y
The desired world origin
Pixel
Origin X
Pixel Origin Y
Defining a Calibration 2D Camera perspective
calibration by looking at a grid
Input is a set of points
representing locations of a grid in space
Input is a set of
points that define a grid in 2D or 3D space
X distance between point
Y distance between point
Grid size X
Grid size Y
OffsetX between successive rows
OffsetY between successive columns
OffsetZ between successive planes
3D camera calibration
Similar to
the 2D case two planes are observed. Each plane a set of points is
defined.
Grid size X
Grid size Y
Grid size Y
OffsetX between successive rows
OffsetY between successive columns
OffsetZ between successive columns
OffsetZ between successive columns