Combined stereovision, color 3D digitizing and motion capture system

A digitizing system comprising:

• a digitizer combining functions of stereovision, color 3D digitizing and motion capture of a target object, comprising:
• a first camera;
• a second camera;
• a first projection arrangement having a first light projector providing lighting for an active 3D range sensing for each of the cameras, and a grating element in front of the first light projector for projection of an encoded pattern on a surface of the target object;
• a second projection arrangement having a second light projector providing lighting for an acquisition of texture information of the target object;
• a base onto which the first and second cameras and the first and second projection arrangements are mounted in fixed relative positions with respect to one another, the cameras having optical axes converging through a single point, one of the light projectors having an optical axis intersecting with the optical axes of the cameras at the single point;
• and
• a communication port connected to the cameras and the light projectors, for reception of control signals setting operation of the cameras and the light projectors and transmission of video signals from the cameras;
• and
• a computer having a port connectable with the communication port of the digitizer, functions controlling operation of the digitizer by generating the control signals for the stereovision, color 3D digitizing and motion capture, and functions for a processing of the video signals received through the port and generation of digitized data as a result of the processing.

A method for digitizing a target object, comprising steps of:

• capturing basic images of the object with first and second cameras without additional illumination of the object, the cameras having optical axes converging through a single point and being aligned in angled directions with respect to each other so that the cameras have fields of view having significant overlapping portions over a depth of measurement including the single point;
• illuminating the object with light in which an encoded pattern is projected;
• capturing structured images with the cameras;
• illuminating the object with light deprived of a pattern;
• capturing texture images with the cameras;
• identifying elements of the encoded pattern in the structured images;
• determining a position of the elements to produce a set of measured points;
• determining 3D coordinates of the measured points using calibration information in respect with position and alignment of the cameras;
• determining coordinates corresponding to each measured point in the texture images to produce a digitized image of the object.

A method for tracking motion of a target object, comprising steps of:

• capturing in parallel sequences of images of the target object with first and second cameras having optical axes converging through a single point and being aligned in angled directions with respect to each other so that the cameras have fields of view having significant overlapping portions over a depth of measurement including the single point;
• detecting control points in a first image of each sequence;
• tracking the control points in the sequences of images;
• determining disparities between the control points in the images from the first camera and the images from the second camera;
• determining 3D positions of the control points in corresponding ones of the images taken at a same time by the first and second cameras by using the disparities and calibration information comprising relative position and angular alignment of the cameras;
• and
• generating trajectories of the control points as sequences of the 3D positions of the control points respectively.