AprilTag are selected as image feature points. The red crosses represent the desired image feature point, the green crosses represent the current image feature point, and the green curves are the trajectories of the feature points' movement. To emphasize the performance of the camera FoV constraint algorithm, trajectories of feature points in the pixel plane are presented in Figure 7. The rectangular box with dotted lines is the camera's FoV preset by the operator. Within the hypothetical camera's FoV, the trajectories of feature points 1 and 2 are obviously beyond the FoV, as illustrated in Figure 7(a). The experiments with our proposed method show that the feature points are successfully constrained in the camera's FoV, as depicted in Figure 7(b). Figure 8 shows the convergence curve of the image plane feature point errors. The image feature point position error curves converge in finite time and are effectively bounded within the predefined position error bounds. The experimental results confirm the