The Analytical Results Error Analysis Of The DLT (Direct Linear Transformation) Method Under Different Conditions

Research objective: In human motion analysis, extraction of the body motioninformation is a very important step, which related to whether you have access to precisekinematics parameters. One of the most important tache of information extracting is thecalibration of space scale. Basically, the three-dimensional analysis of human motion imagingsystems often uses two-dimensional images for three-dimensional reconstruction, and thengives some kinematics, dynamics analysis according to the reconstruction data, so, theprecision proportion of calibration is related to collection precision of information. However,body movement is accurate and complex, influence of three-dimensional reconstruction errorto kenimatics error analysis is the key of three-dimensional analysis. Thus, according toreason of error caused by three-dimensional resolution, According to such error, to discusshow the error can be smaller through relatively effective ways and means, and improve theaccuracy of three-dimensional resolution can provide efficient and reliable theoretical basis.ofanalytical precision improvement in the use of three-dimensional resolution system.Research methods: literature data method and experimental method. On one hand, alarge number of literature reading and study provides theory basis. On the other hand, thereare many experiments in the analisis process, which respectively analyze and compare theerror under different control point quantity, different calibration range and differentcalibration objects, to estimate DLT image analytical results error in different calibrationconditions.Research results:(1) When there is fewer calibration control points, in order to control theprecision of the calibration, evenly distributed control points of calibration framework shouldbe used, which can get high precision.(2) When there sre enough calibration points, and control point evenly distributes incontrol space range, and calibration objects are in the control points range, the precision ofcalibration results is high. The more number of control points, the higher calibrationprecision.(3) In the filming, when the main beam axis angle of two cameras is between80°and100°, the analytical precision is high.(4) Obtain the material used by the image resolution, it is recommended that thecalibration object in the screen size should be accounted for more than60%of the entirescreen in order to ensure the accuracy of the analytical results.Research conclusions: In the filming, control points should evenly distribute in space control range and calibration objects should move in the control points range or spacesurrounded by control points. The number of control points is more if possible. Thecalibration range should be controlled in6m space range from the calibration framework.During the shooting, the research objects should move in the space controlled by controlpoints. If its movement out of control range, it suggests that the images of calibration objectsin two cameras have to locate in two sides of control points, and image control points shouldbigger and clearer to ensure the precision of the calibration. Also, the size of the image shouldabove60%of whole image.