Position/orientation measurement method, and position/orientation measurement apparatus

A position/orientation measurement method of calculating a first position/orientation parameter of an object which is attached to a first image sensing unit used to capture an image of a real space, and has a known position/orientation relationship with the first image sensing unit, comprising:

• a first image coordinate detection step of detecting an image coordinate of a first indicator arranged on the real space from a first image captured by the first image sensing unit;
• a first estimated image coordinate detection step of calculating an estimated image coordinate of the first indicator in accordance with the position/orientation relationship between the first image sensing unit and the first indicator under an assumption that the position and orientation of the first image sensing unit follow a previously calculated second position/orientation parameter;
• a first error coordinate calculation step of calculating a first error coordinate between the image coordinate detected in the first image coordinate detection step and the estimated image coordinate calculated in the first estimated image coordinate detection step on the first image;
• a second image coordinate detection step of detecting an image coordinate of a second indicator arranged on the first image sensing unit or the object from a second image which is captured by a second image sensing unit and includes the object;
• a second estimated image coordinate detection step of calculating an estimated image coordinate of the second indicator in accordance with the position/orientation relationship between the first image sensing unit and the second indicator under an assumption that the position and orientation of the first image sensing unit follow the previously calculated second position/orientation parameter;
• a second error coordinate calculation step of calculating a second error coordinate between the image coordinate detected in the second image coordinate detection step and the estimated image coordinate calculated in the second estimated image coordinate detection step on the second image;
• a correction value calculation step of calculating a correction value used to correct the previously calculated second position/orientation parameter using the first and second error coordinates;
• a correction step of correcting the previously calculated second position/orientation parameter using the correction value;
• and
• a parameter calculation step of calculating the first position/orientation parameter of the object, which has the known position/orientation relationship with the first image sensing unit, using the second position/orientation parameter corrected in the correction step.

A position/orientation measurement method of calculating a position and orientation of an image sensing device as an object to be measured, which captures an image of a scene, comprising:

• a detection step of detecting a feature value associated with an image coordinate of a first indicator arranged in the scene from the image captured by the image sensing device;
• a measurement step of measuring a three dimensional position of a second indicator arranged on the image sensing device;
• and
• a position/orientation calculation step of calculating the position and orientation of the image sensing device using the feature value associated with the image coordinate of the first indicator detected in the detection step, and the three dimensional position of the second indicator measured in the measurement step.

A position/orientation measurement apparatus for calculating a position and orientation of an object, comprising:

• subjective image sensing unit, attached to the object, adapted to capture an image of a scene;
• objective viewpoint image sensing unit adapted to capture an image of the object;
• first detection unit adapted to detect a feature value associated with an image coordinate of a first indicator arranged in the scene from a first image captured by said subjective viewpoint image sensing unit;
• second detection unit adapted to detect a feature value associated with an image coordinate of a second indicator arranged on the object or said subjective viewpoint image sensing unit from a second image captured by said objective viewpoint image sensing unit;
• and
• position/orientation calculation unit adapted to calculate the position and orientation of the object using the feature value associated with the image coordinate of the first indicator detected by said first detection unit, and the feature value associated with the image coordinate of the second indicator detected by said second detection unit.