# Pose Measurement Method Based on Machine Vision and Novel Directional Target
## 4 Results
### Pose-Solving Simulation Experiment  
Based on the above simulation platform, after obtaining the calibration results, the corresponding pictures are generated by simulation according to the pre-set completed angles. The simulation experiment is mainly divided into two parts. One is to detect the error of the system itself in four different pose situations; the other is to calculate the repeatability error of the system by subtracting the system error after obtaining the results. To cover more pose angles and to demonstrate the measurement range of the system, four prominent cases of simulated curves were selected: a smaller angle of rotation in the positive direction, a smaller angle of rotation in the negative direction, a larger angle of rotation in the positive direction, and a larger angle of rotation in the negative direction. Fifteen diagrams were generated for each case simulation for calculation. The simulation results are shown in Figures 6-9, respectively. The line chart above represents the pitch angle error value, the line chart below represents the roll angle error value, the green line represents the average error value of the attitude angle, and the red line represents the maximum error value of the attitude angle. The combination of the angle of the upper and lower line graphs corresponds to complete attitude angle errors of the simulation graph. Figure 5: Reprojection error of each feature point. Figure 8: Larger angle of rotation in the positive direction. Figure 6: Smaller angle of rotation in the positive direction. Figure 7: Smaller angle of rotation in the negative direction. From the results shown in Figures 6-9, it can be seen that after using this method, the measurement error of the tumbling angle perpendicular to the optical axis direction is \(0.001^{\circ}\) at the maximum, and the average error is \(0.00044^{\circ}\) at the maximum; the measurement error of the pitch angle is \(0.008^{\circ}\) at the maximum, and the average error is \(0.00551^{\circ}\) at the maximum. The measurement error of the roll angle is generally much smaller than that of the pitch angle. The accuracy is inversely proportional to the pitch angle, and the angular error in the roll direction is more stable. To further simulate the stability of the system to solve the pose, the two perspectives of roll angle \(10^{\circ}\), pitch angle \(5^{\circ}\) and roll angle \(-20^{\circ}\), pitch angle \(-10^{\circ}\) were further selected, and 15 pictures were simulated to be generated for each pose, respectively. Their average error was used as the system error. The error of each image subtracted from the system error value was used as the error of the repeatability accuracy. The experimental results are shown in Figures 10 and 11. The line chart above represents the pitch angle error value, the line chart below represents the roll angle error value, the green line represents the average error value of the attitude angle, and the red line represents the maximum error value of the attitude angle. The combination of the angle of the upper and lower line graphs corresponds to the complete attitude angle errors of the simulation graph. Figure 10: Repeat accuracy error at \(10^{\circ}\) roll angle and \(5^{\circ}\) pitch angle. Figure 9: Larger angle of rotation in the negative direction. From the results shown in Figures 10 and 11, it can be seen that after using this method, the maximum error of repeated measurement of the tumble angle perpendicular to the direction of the optical axis is 0.00008\({}^{\circ}\), and the average maximum mistake of repeated measurement is 0.00003\({}^{\circ}\); the maximum error of repeated measurement of the pitch angle is 0.0004\({}^{\circ}\), and the maximum average error of repeated measurement is 0.00013\({}^{\circ}\). It can be analysed that the repeated size for a short period has a very small variation of error, and the error is randomly distributed.