Binocular-vision-based method for tracking fruit space attitude and fruit space motion

A computer implemented method for tracking fruit space attitude and fruit space motion, wherein the computer is configured to carry out the steps comprising:

• (1) marking three feature points C1, C2, C3 on a surface of a fruit;
• (2) establishing a connected base coordinate system by taking a junction of the fruit and a fruit stem as an origin, a X axis, a Y axis, and a Z axis of the connected base coordinate system are marked as a X connected-axis, a Y connected-axis and a Z connected-axis, respectively, and the origin of the connected base coordinate system is marked as O1, an end point of the unit vector in a positive direction of the X connected-axis is marked as X1, an end point of the unit vector in a positive direction of the Y connected-axis is marked as Y1, an end point of the unit vector in a positive direction of the Z connected-axis is marked as Z1;
• (3) establishing a public reference base coordinate system;
• (4) statically photographing the three feature points on the surface of the fruit and connected base coordinate system points c established at the junction of the fruit and the fruit stem, using software to store the photographed images, and using software to process the feature points and connected base coordinate system points O1, X1, Y1, Z1 in the images, acquiring a absolute coordinate of the feature points C1, C2, C3 and the connected base coordinate system points O1, X1, Y1, Z1, and then acquiring an inherit relationship between the feature points and the connected base coordinate system;
• (5) photographing the fruit dynamic motion, using software to store each frame of the image in the photographed video, using software to process the feature points in the images to acquiring the absolute coordinate of the feature points on the fruit surface, according to an inherent relationship between the feature points and the connected base coordinate system, the absolute coordinate of each frame of image corresponding to the connected base coordinate system points O1, X1, Y1, Z1 at each moment being calculated by inverse rotation transformation, and calculating an angle between the vector {right arrow over (O1Z1)} at each moment and the Z axis in the public reference base coordinate system through the space vector angle formula, and the angle representing a swing posture of the fruit;
• (6) rotating the {right arrow over (O1Z1)} at each moment to a position that coincides with the Z axis in the public reference base coordinate system, and calculating an angle between the rotated {right arrow over (O1Z1)} and the X axis in the public reference base coordinate system, the angle representing a twisting posture of the fruit;
• and
• (7) setting moments corresponding to two adjacent frames to t+1 moment and t moment, and calculating a displacement of the point O1 along the X axis, Y axis and Z axis of the public reference base coordinate system at t+1 moment and t moment respectively, calculating an instantaneous speed along the X axis, an instantaneous speed along the Y axis, and an instantaneous speed along the Z axis of the fruit at t moment according to the displacement, calculating an instantaneous acceleration along the X axis, an instantaneous acceleration along the Y axis and an instantaneous acceleration along the Z axis of the fruit at t moment according to the instantaneous speed, calculating a swing angular displacement of the fruit in a time interval between the two adjacent frames of images, sequentially calculating a swing angular speed of the fruit at t moment and a swing angular acceleration of the fruit at t moment via the swing angular displacement, and calculating a torsion angular speed of the fruit at t moment and a torsion angular acceleration of the fruit at t moment according to the torsion angular degree from t moment to t+1 moment.