# Checkerboard Calibration Edit Control

The Checkerboard Calibration tool edit control provides a graphical user interface to the CalibCheckerboardTool tool, which you use to calibrate an application so that it returns results in meaningful, real-world values. By adding a Checkerboard Calibration tool to your application, the tools you use to analyze an image can return results in a specific unit of measurement such as inches, centimeters, millimeters, and so on. See the topic Checkerboard Calibration Tool for more information.

The following figure shows the Checkerboard Calibration tool edit control:

See the topic Control Reference for a description of the buttons along the top of the edit control. The Copy Region tool edit control supports the following image buffers:

- The Current.InputImage buffer contains the last image received from an image-acquisition tool. Once your deploy your application, the tool accepts images of the objects you want to inspect and adds the calibrated coordinate space to the coordinate space tree of the input image.

- The Current.CalibrationImage buffer contains the image of the calibration pattern copied from the Current.InputImage buffer as you configure the tool, with graphics to indicate found vertices.

  To configure a Checkerboard Calibration tool and generate a calibrated coordinate space, the Current.InputImage buffer must be of a calibration plate before you to copy it to the Current.CalibrationImage buffer.

- The LastRun.OutputImage buffer contains the output image generated each time the tool runs. If the 2D transformation is linear, then the output image resembles the input image. If the 2D transformation is nonlinear, then the tool warps the output image to remove the effects of any perspective and radial distortion present in the calibration image.

- The LastRun.InputImage buffer contains the last image processed by the tool along with any graphics you enable from the Graphics tab.

- If you use the tool to generate a nonlinear 2D transformation, the tool also supports a Current.UndistortedCalibrationImage buffer, which contains a warped image of the calibration plate to remove any known distortion. You can also use this undistorted image to specify a destination rectangle.

Note: The Checkerboard Calibration tool supports both checkerboard and grid-of-dots calibration plates. Cognex recommends the use of checkerboard calibration plates with the CalibCheckerboardTool. VisionPro supports grid-of-dots plates for existing applications.

See the following topics for more information: