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A calibrated camera is tested and adjusted by the user for quality control. This testing can occur before and after use, or between shots, depending on how and where the camera is being used. It can be time consuming, and is only recommended in cases where very high image quality is required and extreme precision is necessary. Otherwise, the default controls on a camera are typically sufficient to meet the needs of the average user.
In the calibration testing, an operator uses a known image, like a printed grid or array, as a reference point. The technician can aim the camera at the reference and note the center point, amount of distortion created by the lens, and focal length. It is possible to adjust the camera to change these characteristics, if necessary. This process results in a calibrated camera, one which has been tested to confirm the quality and consistency of images.
One application for such devices is in robotics. Advanced robot cameras may need to be calibrated to allow the robot to engage in complex coordinated tasks. If the robot's vision is compromised because the cameras aren't correctly adjusted, it may fail to perform as expected. For instance, it might miss a doorway or fail to track a line adequately because its camera doesn't have the right center point, or because it cannot perform accurate measurements since the focal length is off.
Three dimensional imaging also requires careful camera calibration. This includes medical imaging studies as well as filming for three dimensional movies. A calibrated camera works with the others in the array to generate a stable, reliable image. Cameras that operate out of synch or are imprecisely adjusted can create blurry or confused images. Differences may be too subtle to be visible with the naked eye, but could cause eyestrain or compromise the quality of the finished images.
Researchers also use calibrated camera technology when they make and record observations. They require reliable images to create replicable experiments and document their results for the benefit of other interested parties. Errors in calibration can translate into significant inaccuracies when people are working with images in fields like astronomy, where vast distances are being measured.
Kits are available for use with a calibrated camera. Some manufacturers produce reference images and instructions for calibration and people can also use third party products. It is important to perform calibration measurements consistently and in accordance with directions for the best results. Failure to do so may result in a compromised final image.