From Wikipedia, the free encyclopedia

Calibration refers to the process of determining the relation between the output (or response) of a measuring instrument and the value of the input quantity or attribute, a measurement standard. In non-specialized use, calibration is often regarded as including the process of adjusting the output or indication on a measurement instrument to agree with value of the applied standard, within a specified accuracy. For example, a thermometer could be calibrated so the error of indication or the correction is determined, and adjusted (e.g. via calibration constants) so that it shows the true temperature in Celsius at specific points on the scale. Calibration also can refer to judgments made by a prognosticator. For example, if a weather forecaster is properly calibrated, it will rain on 80% of the days on which she says "there is an 80% chance of rain today".

In many countries a National Metrology Institute (NMI) will exist which will maintain primary standards of measurement (the main SI units plus a number of derived units) which will be used to provide traceability to customer's instruments by calibration. The NMI supports the metrological infrastructure in that country (and often others) by establishing an unbroken chain, from the top level of standards to an instrument used for measurement. Examples of National Metrology Institutes are NPL in the UK, NIST in the United States, PTB in Germany and many others. Since the Mutual Recognition Agreement was signed it is now straightforward to take traceability from any participating NMI and it is no longer necessary for a company to obtain traceability for measurements from the NMI of the country in which it is situated.

See [1] for more information on the Mutual Recognition Agreement. See [2] for the international metrology framework

For a calibration to be of any value it must be accompanied by a traceable uncertainty statement to an stated confidence level. This is evaluated through careful uncertainty analysis.

In computing, an interactive whiteboard pen or other input method can be calibrated so that relation between the physical pen position and the position of the cursor on the screen is established and properly adjusted.

• Calibration (statistics)
• Metrology
• Color calibration - used to calibrate a computer monitor or display.
• Scale test car - a device used to calibrate weighing scales that weigh railroad cars.