# ExtractCalibration

ExtractCalibration creates a 2D transformation, in real-world coordinates, based on the "undistorted" image returned by a TransformImage function, and retrieves calibration data contained in the Image data structure output by the ScaleImage function.

Note: For the ScaleImage function to work correctly with ExtractCalibration, the functions' Image parameter must be set as a reference to a function that returns a Calib data structure.

## About ExtractCalibration

When a TransformImage function is added, ExtractCalibration is automatically inserted to associate a 2D transformation to the real-world coordinates defined by the image generated by a TransformImage function. Using the Image data structure generated by the TransformImage function as its sole input, ExtractCalibration returns a Calib data structure, which can be used as a reference when a TransBlobsToWorld, TransEdgesToWorld, TransFixtureToWorld, TransPatternsToWorld, and/or TransPixelToWorld function was being used on the undistorted image generated by a TransformImage function. ExtractCalibration and TransformImage can be associated together using the CalibrateImage function.

Separately, ExtractCalibration can be inserted into the spreadsheet and its Image parameter set as a reference to the Image data structure output by the ScaleImage function. ExtractCalibration then retrieves the calibration data being fed into these functions.

Note: The output of any vision tool that reports in real-world coordinates cannot be used as a fixture or region input to another vision tool.

## ExtractCalibration Inputs

Parameter | Description
Image | This argument must reference a spreadsheet cell that contains a valid Image data structure created by a ScaleImage or TransformImage function. When automatically inserted in conjunction with a TransformImage function, by default, the cell referenced is the cell containing the Image data structure returned by TransformImage. Otherwise, the cell referenced is cell A1, the cell containing the Image data structure.

## ExtractCalibration Outputs

Returns | A Calib data structure containing the coefficients that define the transformation between the two coordinate systems.