Apparatus and method for calibrating detectors in a computed tomography scanner

An apparatus for calibrating a tomographic scanner to reduce detector channel differential errors in a plurality of detector channels associated with an array of detectors, said array of detectors being adapted to receive radiation from a radiation source to generate scan data for an object through which the radiation passes, said apparatus comprising:

• data acquisition subsystem constructed and arranged so as to acquire a plurality of sets of scan data for a calibration object at a respective plurality of thicknesses of the calibration object;
• a high pass filter arrangement constructed and arranged so as to identify errors in the scan data acquired for a detector channel at the respective plurality of thicknesses of the calibration object;
• and
• an error compensation subsystem constructed and arranged so as to fit the identified errors to a parametric equation with respect to a value associated with each thickness, said parametric equation being used during subsequent scanning of actual objects to adjust scan data generated by the corresponding detector channel.

A method of calibrating a tomographic scanner to reduce detector channel differential errors in a plurality of detector channels associated with an array of detectors, said array of detectors being adapted to receive radiation from a radiation source to generate scan data for an object through which the radiation passes, said method comprising:

• acquiring a plurality of sets of scan data for a calibration object at a respective plurality of thicknesses of the calibration object;
• identifying errors in the scan data acquired for a detector channel at the respective plurality of thicknesses of the calibration object;
• and
• fitting the identified errors to a parametric equation with respect to a value associated with each thickness by applying a least square analysis to the errors, said parametric equation being used during subsequent scanning of actual objects to adjust scan data generated by the corresponding detector channel.

An apparatus for calibrating a tomographic scanner to reduce detector channel differential errors in a plurality of detector channels associated with an array of detectors, said array of detectors being adapted to receive radiation from a radiation source to generate scan data for an object through which the radiation passes, said apparatus comprising:

• a data acquisition subsystem constructed and arranged so as to acquire a plurality of sets of scan data for a calibration object at a respective plurality of thicknesses of the calibration object;
• a high pass filter arrangement constructed and arranged so as to identify errors in the scan data acquired for a detector channel at the respective plurality of thicknesses of the calibration object;
• and
• an error compensation subsystem constructed and arranged so as to fit the identified errors to a parametric equation with respect to a value associated with each thickness by applying a least square analysis to the errors, said parametric equation being used during subsequent scanning of actual objects to adjust scan data generated by the corresponding detector channel.