Definition of ground truth in US English:

ground truth


  • 1A fundamental truth. Also: the real or underlying facts; information that has been checked or facts that have been collected at source.

  • 2In remote sensing: information obtained by direct measurement at ground level, rather than by interpretation of remotely obtained data (as aerial or satellite images, etc.), especially as used to verify or calibrate remotely obtained data.

  • 3Information obtained by direct observation of a real system, as opposed to a model or simulation; a set of data that is considered to be accurate and reliable, and is used to calibrate a model, algorithm, procedure, etc. Also: (specifically in image recognition technologies) information obtained by direct visual examination, especially as used to check or calibrate an automated recognition system.


Mid 19th century; earliest use found in Henry Ellison (1811–1890). From ground + truth [adverb], in sense 1 probably after German Grundwahrheit.


ground truth

/ˈɡraʊnd ˌtruːθ/