Calibrate Optics

This option calibrates the optics on the system. Four separate calibrations are supported (depending on hardware and calibration artifact available):

If your zoom cell automatically calibrates, then you won't need to perform a specific magnification calibration. Instead, a message that the calibration is done appears.

To calibrate the optics:

  1. On the Calibrate Probe dialog box, from the drop-down list, select Calibrate Optics.

  2. Click Calibrate to open the Calibrate Optics dialog box.


Calibrate Optics dialog box

When the calibration procedure starts, DO NOT move the calibration standard.

  1. In the Calibration Standard area, select the calibration standard that corresponds to the type of calibration standard you received with your system. Supported standards include:

  1. From the Calibrate area, select the needed options.

  1. From the Settings area, select the calibration settings:

  1. Click the Calibrate button. A message box appears, stating that your calibration standard must be clean and aligned with the X axis. You must also ensure that the standard is face up.

Although the calibration processing employs noise and dirt rejection techniques, a dirty calibration standard may trigger calibration failures or yield less accurate measurement values. Be sure to clean any dust, dirt, fingerprints, or other material from the calibration standard's glass portion. Use a mild non-depositing cleaning solution, such as rubbing alcohol, and a soft, lint-free cloth. Be sure to also clean the stage glass where the calibration standard is positioned. For proper cleaning techniques, refer to your hardware documentation. If the stage carrying the glass standard might move during the calibration sequence, hold the standard to the stage with clay or putty.

  1. Place the calibration artifact on the stage so the length of the standard runs along the X axis of the machine. For the ROI slides, ensure that the larger targets are on the left (-X direction) and the smaller targets on the right (+X direction). Verify the alignment with the X axis by watching the horizontal line on the standard while traversing the stage X axis. The line should remain in the field of view and ideally very near center.

  2. Click the OK button. Additional messages appear, requesting that you center the target.

  3. Place a target so that it completely fits within the camera's view. This target should be roughly centered within the field of view and focused. The focus does not need to be optimal, just a good starting place for the software focus process.

  4. Click the OK button, and if you have a DCC machine, it automatically focusses on the target. If you have a manual machine, a prompt is displayed for you to focus on the target.

  5. Use the manual controls to move the optical measuring system and roughly center the rectangle or square calibration standard in the field of view. PC-DMIS determines the target size based on your optics.

Do not change the Z position or the focus during the rest of the calibration procedure.

  1. Click the OK button after you have centered the target. The calibration routine automatically proceeds as follows based on the calibration options selected:

Pixel Size Calibration

Focus Calibration

Camera Rotation Calibration

Target centered on Concentric Circles of HexagonMI Standard

The Calibration Process continues by focusing and taking a series of measurements at different magnification levels. This establishes that the optical center and focal depth coincide through the focal range. This means if you focus and measure a circle at one magnification, it gives the same XYZ position at another magnification.

  1. Near the end of calibration, PC-DMIS generates and runs a series of dynamic measurement routines in the background. It does this to perform a basic verification that measures a subset of the calibration data. As the software measures each target in these measurement routines, the Status area on the Calibrate Optics dialog box updates its message to show the step number.

Status Message Showing Pixel Size and Error

  1. When the pixel verification finishes, PC-DMIS may display a Verification Complete dialog box. This dialog box appears only if a verification data point is out of tolerance. The dialog box contains columns showing the different steps that were measured, the pixel size and errors. A <- symbol to the right of the error value indicates that the error is larger than the specified tolerance.

Verification Complete dialog box

If this dialog box appears, you can choose to run the verification again, by clicking Run Again. This helps determine if any errors were simply anomalies in the verification. If the verification fails multiple times, try re-running the entire pixel size calibration. If both the calibration and the verification fail repeatedly, contact Hexagon Technical Support.

You can click Continue to accept the results of the verification.

The ProbeCal section of the PC-DMIS Settings Editor contains registry entries that affect the pixel size calibration.

  1. Click the Close button to close the Calibrate Optics dialog box. The software also writes the calibration results to the Calibration Results dialog box so that you can view the results of the calibration later. To view the results, click the Results button on the Probe Utilities dialog box:

Calibration Results dialog box

You have now calibrated the Field of View. Repeat this process for each lens you wish to use on the machine.

On a CMM-V camera, just the FOV for the A0B0 wrist angle needs to be calibrated. You may wish to place some reflective white paper on the CMM table under the "Calibration Artifact Holder" (Part Num. CALB-0001). The "Calibration Artifact Holder" includes a glass slide (CALB-0002) and a ring gage (CALB-0003) used for calibration of the CMM-V camera.