Calibrate
Utilizing four user-specified points, Calibrate creates a 2D transformation to convert between pixel and real-world coordinate systems.
About Calibrate
The Calibrate function requires user-specified points, expressed in two different coordinate systems: The real-world physical coordinate system of the object being captured, and the pixel coordinates of the object's image. To accomplish this, Calibrate requires the extraction of features from an image using a Vision Tools. Then, those feature locations are entered as both real-world and pixel coordinates.
During the calibration phase, an image is acquired that contains features with known locations in real-world coordinates. Using a vision tool, such as FindPatMaxPatterns FindLine, the features in the image are located and reported in pixel coordinates.
Next, both the pixel and real-world coordinates are entered as the Pixel Point and World Point parameters; for the Pixel Point coordinates, Cell References to a vision tool's X and Y values is used, while a numeric value is entered to express the World Point real-world coordinates. Then the tool computes the 2D transformation between the pixel and real-world coordinates, producing a Calib structure that represents the transformation.
Calibrate also accounts for the following transformations:
- translation in two dimensions
- rotation about three axes
- scale in two dimensions
- perspective distortion
- parallelogramming or skewing
Note:
|
Calibrate Inputs
Input | Description | ||||
---|---|---|---|---|---|
Pixel Point 0 to N |
Specifies the pixel coordinates of a pixel-to-world association.
|
||||
World Point 0 to N |
Specifies the real-world coordinates of a pixel-to-world association.
|
Calibrate Outputs
Returns |
A Calib data structure containing the coefficients that define the transformation between the two coordinate systems. |