Calibration pattern (1) for geometrically calibrating an X-ray imaging device for generating three-dimensional images of an object by reconstruction from two-dimensional projections of said object, the calibration pattern (1) comprising a volume support ( 20) provided with markers (10) with radiological absorption contrasted with respect to the volume support (20), the markers (10) being distributed according to a three-dimensional figure. The markers (10) are divided into subsets of markers distributed along respective substantially parallel straight lines so that the two-component sequences can be constructed from the respective subset of markers, each betwee sequence comprising a single birapport for each quadruplet markers in which the markers are ordered according to an order depending on the order numbers of the respective markers along the line according to which they are aligned according to a predefined first direction, said order being common to all the birapports, and when a sub the set of markers comprises at least five markers, the order of the reports in the respective birapport sequences according to a predefined rule common to all the binder sequences. Mire de calibration (1) destinée à calibrer géométriquement un dispositif d'imagerie par rayons X destiné à générer des images tridimensionnelles d'un objet par reconstruction à partir de projections bidimensionnelles dudit objet, la mire de calibration (1) comprenant un support volumique (20) muni de marqueurs (10) à absorption radiologique contrastée par rapport au support volumique (20), les marqueurs (10) étant répartis selon une figure tridimensionnelle. Lesmarqueurs (10) sont répartis en sous-ensembles de marqueurs répartis selon des droites respectives sensiblement parallèles de façon que des séquences de birapports puissent être construites à partir des sous-ensembles de marqueurs respectifs, chaque séquence de birapports comprenant un unique birapport pour chaque quadruplet de marqueu
