A system for calibrating a dental intraoral imaging apparatus configured to image a surface contour of an object, the system comprising: the dental intraoral imaging apparatus comprising: a first sensing apparatus, the first sensing apparatus comprising at least one lens and a sensor that is configured to obtain one or more images of at least one surface position, and a projector; a calibration target comprising: a spatial light modulator configured to form a prescribed set of calibration patterns including a series of codeword patterns; wherein the spatial light modulator is an LCD display target device or an active display target device; wherein the active display target device is used for calibration of the projector-camera system; and a display plane configured to display the prescribed set of calibration patterns; and a computer system; wherein the display plane of the calibration target is arranged to correspond to the at least one surface position; wherein the first sensing apparatus is configured to capture the displayed prescribed set of calibration patterns; and wherein the computer system is configured to calibrate the dental intraoral imaging apparatus by: acquiring and processing the captured displayed set of calibration patterns; determining a coordinate correspondence between 2D coordinates of a calibration target coordinate and 2D coordinates of the dental intraoral imaging apparatus based on the captured displayed set of calibration patterns; and by determining calibration parameters for the dental intraoral imaging apparatus according to the determined coordinate correspondence; wherein acquiring at least one image of the calibration target is performed for more than one pose of the calibration target. the dental intraoral imaging apparatus comprising: a first sensing apparatus, the first sensing apparatus comprising at least one lens and a sensor that is configured to obtain one or more images of at least one surface position, and a projector; a calibration target comprising: a spatial light modulator configured to form a prescribed set of calibration patterns including a series of codeword patterns; wherein the spatial light modulator is an LCD display target device or an active display target device; wherein the active display target device is used for calibration of the projector-camera system; and a display plane configured to display the prescribed set of calibration patterns; and a spatial light modulator configured to form a prescribed set of calibration patterns including a series of codeword patterns; wherein the spatial light modulator is an LCD display target device or an active display target device; wherein the active display target device is used for calibration of the projector-camera system; and a display plane configured to display the prescribed set of calibration patterns; and a computer system; wherein the display plane of the calibration target is arranged to correspond to the at least one surface position; wherein the first sensing apparatus is configured to capture the displayed prescribed set of calibration patterns; and wherein the computer system is configured to calibrate the dental intraoral imaging apparatus by: acquiring and processing the captured displayed set of calibration patterns; determining a coordinate correspondence between 2D coordinates of a calibration target coordinate and 2D coordinates of the dental intraoral imaging apparatus based on the captured displayed set of calibration patterns; and by determining calibration parameters for the dental intraoral imaging apparatus according to the determined coordinate correspondence; acquiring and processing the captured displayed set of calibration patterns; determining a coordinate correspondence between 2D coordinates of a calibration target coordinate and 2D coordinates of the dental intraoral imaging apparatus based on the captured displayed set of calibration patterns; and by determining calibration parameters for the dental intraoral imaging apparatus according to the determined coordinate correspondence; wherein acquiring at least one image of the calibration target is performed for more than one pose of the calibration target.