Calibrating Images

This section describes how to calibrate your imaging system, save calibration information, and attach calibration information to an image. Calibrate your imaging system if you need to compensate for distortion or make accurate measurements in real-world units.

Complete the following general steps to calibrate your imaging system:

1. Define reference points.

   Note  Simple calibration does not require reference points.

2. Learn the calibration information.
3. Define a calibration axis system.

After you calibrate your imaging system, you can attach the calibration information to an image. Refer to the Attach Calibration Information section for more information. Then, depending on your needs, you can perform one of the following steps:

• Use the real-world measurements options on Vision VIs to get real-world particle shape parameters without correcting the image.
• Use the calibration information to convert pixel coordinates to real-world coordinates without correcting the image.
• Create a distortion-free image by correcting the image for perspective errors and lens aberrations.

Calibration Invalidation

Any image processing operation that changes the image size or orientation voids the calibration information in a calibrated image. Examples of VIs that void calibration information include the IMAQ Resample, IMAQ Extract, IMAQ ArrayToImage, and IMAQ Unwrap VIs.