Image registration error measuring device, method and system

The invention provides an image registration error measuring device, method and system. The method comprises the steps of scanning an object to obtain CT scanning data M1 and C-shaped arm scanning data F1; removing the steel ball image information in the M1 to obtain an image M2; carrying out image processing on the F1, and removing steel ball image information in the F1 to obtain an image F2; performing image registration on the M2 data and the F2 data to obtain a registration mapping relation T; dividing the steel balls in the M1, and extracting center point set coordinates PM of the steel balls; dividing the steel balls in the F1, and extracting center point set coordinates PF of the steel balls; and based on the registration mapping relation T, mapping the central point set coordinatePM to obtain a point set coordinate PM1, and if the PM1 coincides with the PF, determining that no error exists in image registration, otherwise, determining that the error exists in the image registration. The registration e