An integrated novel method of recognizing huge target is described that combines some relatively mature image processing techniques such as edge detection, thresholding, morphology, image segmentation and so forth. Af...An integrated novel method of recognizing huge target is described that combines some relatively mature image processing techniques such as edge detection, thresholding, morphology, image segmentation and so forth. After thresholding the edge image obtained by using Sobel operator, erosion is firstly used to reduce noise and extrusive pixels; then dilation is used to expand some separated pixels into various regions, after that the image segmentation technique is utilized to distinguish the target region with a criterion. The location of the target is also offered. Each technique adopted herein seems not complicated at all, the experimental results demonstrate the efficiency of the combination of these techniques. It is its high computational speed and remarkable robustness resulting from its simplicity that make the method promise to be applied in practical problems requiring real time processing.展开更多
Solar sail is a new type of spacecraft for deep space exploration,which flies by the pressure of sunlight.The attitude of the sail determines its orbit,so altitude control plays an important role in the mission.Howeve...Solar sail is a new type of spacecraft for deep space exploration,which flies by the pressure of sunlight.The attitude of the sail determines its orbit,so altitude control plays an important role in the mission.However,the large flexible structure leads to some difficulty in attitude control.This paper establishes the reduced dynamic model of a flexible solar sail with foreshortening deformation,and coupling with its attitude and vibration.As usual,large angle maneuvering will lead to the vibration of flexible structure,so the time optimal control of solar sail maneuvering is considered.Bang-Bang control of the solar sail generates large amplitude and sustained vibration,while the combined control based on input shaping can eliminate the vibration efficiently.With the comparison of two reduced models,it is demonstrated that the choice of two models depends on the attention to the stretching deformation.展开更多
文摘An integrated novel method of recognizing huge target is described that combines some relatively mature image processing techniques such as edge detection, thresholding, morphology, image segmentation and so forth. After thresholding the edge image obtained by using Sobel operator, erosion is firstly used to reduce noise and extrusive pixels; then dilation is used to expand some separated pixels into various regions, after that the image segmentation technique is utilized to distinguish the target region with a criterion. The location of the target is also offered. Each technique adopted herein seems not complicated at all, the experimental results demonstrate the efficiency of the combination of these techniques. It is its high computational speed and remarkable robustness resulting from its simplicity that make the method promise to be applied in practical problems requiring real time processing.
文摘Solar sail is a new type of spacecraft for deep space exploration,which flies by the pressure of sunlight.The attitude of the sail determines its orbit,so altitude control plays an important role in the mission.However,the large flexible structure leads to some difficulty in attitude control.This paper establishes the reduced dynamic model of a flexible solar sail with foreshortening deformation,and coupling with its attitude and vibration.As usual,large angle maneuvering will lead to the vibration of flexible structure,so the time optimal control of solar sail maneuvering is considered.Bang-Bang control of the solar sail generates large amplitude and sustained vibration,while the combined control based on input shaping can eliminate the vibration efficiently.With the comparison of two reduced models,it is demonstrated that the choice of two models depends on the attention to the stretching deformation.
