Motion Compensation Technology Research Articles

Current Research Status of Respiratory Motion for Thorax and Abdominal Treatment: A Systematic Review.

Malignant tumors have become one of the serious public health problems in human safety and health, among which the chest and abdomen diseases account for the largest proportion. Early diagnosis and treatment can effectively improve the survival rate of patients. However, respiratory motion in the chest and abdomen can lead to uncertainty in the shape, volume, and location of the tumor, making treatment of the chest and abdomen difficult. Therefore, compensation for respiratory motion is very important in clinical treatment. The purpose of this review was to discuss the research and development of respiratory movement monitoring and prediction in thoracic and abdominal surgery, as well as introduce the current research status. The integration of modern respiratory motion compensation technology with advanced sensor detection technology, medical-image-guided therapy, and artificial intelligence technology is discussed and analyzed. The future research direction of intraoperative thoracic and abdominal respiratory motion compensation should be non-invasive, non-contact, use a low dose, and involve intelligent development. The complexity of the surgical environment, the constraints on the accuracy of existing image guidance devices, and the latency of data transmission are all present technical challenges.

Hierarchical coupling control of cable-driven multi-loop crane for underactuated positioning

For the low-cost anti-swing retrofit of existing offshore heavy cranes, a (2-UPPU/UPU)UP multi-loop configuration with six cable-driven prismatic pairs and a UP underactuated pendulum is introduced. Each UPPU branch contains a fast-moving prismatic pair and a slow-moving one. A configuration tracking method utilizing three slow cable motions in 2-UPPU/UPU is proposed by motion compensation technology. A multi-loop underactuated end positioning scheme is given to achieve the cargo's horizontal positioning in inertia frame, i.e., two fast cable motions in 2-UPPU are used to drive four states comprising their tracking trajectories and two cargo swings, which frees the wave compensation and swing suppression task from crane joints and retains the original crane system. A hierarchical coupling controller with a special coupling relation matrix is designed, where the matrix-based sub-controller fusion technique provides a standardized design approach with distinct physical meaning for the application of hierarchical methodology in underactuated multi-loop systems. The stability analysis by Lyapunov method reveals multiple coupling relation matrices matching stability conditions, giving birth to five attractive coupling control modes. Simulations and experiments are conducted to compare and verify performance.

Prediction and Compensation Model of Longitudinal and Lateral Deck Motion for Automatic Landing Guidance System

This paper mainly studies the longitudinal and lateral deck motion compensation technology. In order to ensure the safe landing of the carrier-based aircrafts on the flight decks of carriers during the landing process, it is necessary to introduce deck motion information into the guidance law information of the automatic landing guidance system when the aircraft is about to land so that the aircraft can track the deck motion. To compensate the influence of the height change in the ideal landing point on the landing process, the compensation effects of the deck motion compensators with different design parameters are verified by simulation. For further phase-lead compensation for the longitudinal automatic landing guidance system, a deck motion predictor is designed based on the particle filter optimal prediction theory and the AR model time series analysis method. Because the influence of up and down motions on the vertical motion of the ideal landing point is the largest, the compensation effects of the designed predictor and compensator are simulated and verified based on the up and down motion of the power spectrum. For the compensation for the lateral motion, a tracking strategy of the horizontal measurement axis of the inertial stability coordinate system to the horizontal axis of the hull coordinate system (center line of the deck) is proposed. The tracking effects of the horizontal measurement axis of the designed integral and inertial tracking strategies are simulated and compared. Secondly, the lateral deck motion compensation commands are designed, and the compensation effects of different forms of compensation commands are verified by simulations. Finally, the compensation effects for the lateral deck motion under integral and inertial tracking strategies are simulated and analyzed.

An Imaging Method for Spaceborne Cooperative Multistatic SAR Formations With Nonzero Cross-Track Baselines

Spaceborne multistatic synthetic aperture radar (M-SAR) formations can deploy multiple spatially separated receiving phase centers along the along-track (AT) direction to achieve high-resolution wide-swath. However, the cross-track (XT) separation between the spacecraft is inevitable due to the formation design like orbital safety and application potential like the XT interferometry. In addition, the different motion vectors of two or more satellites caused by the Helix formation will lead to the difference of the Doppler parameters at the same range gate. Therefore, nonzero XT baselines and space-variant characteristics pose new challenges to the focusing and phase-preserving of the M-SAR imaging. To this end, an imaging method for spaceborne cooperative M-SAR formations with nonzero XT baselines is proposed in this paper. Firstly, an spaceborne cooperative M-SAR formation is demonstrated. Afterwards, the imaging method is described in detail. The motion compensation technology and the idea of partitioned equivalent velocity are adopted to solve the problems of nonzero XT baselines and space-variant characteristics, respectively. Finally, the simulations of point targets and distributed targets are carried out to verify the proposed method, and the results show that the precise focusing of spaceborne cooperative M-SAR with nonzero XT baselines can be achieved by the proposed imaging method.

LiDAR Point Cloud Compression by Vertically Placed Objects Based on Global Motion Prediction

A point cloud acquired through a Light Detection And Ranging (LiDAR) sensor can be illustrated as a continuous frame with a time axis. Since the frame-by-frame point cloud has a high correlation between frames, a higher compression efficiency can be obtained by using an inter-prediction scheme, and for this purpose, Geometry-based Point Cloud Compression (G-PCC) in the Moving Picture Expert Group (MPEG) opened Inter-Exploratory Model (Inter-EM) which experiments on continuous LiDAR based point cloud frames compression through inter-prediction. The points of the LiDAR based point cloud have two different types of motion: global motion brought about by a vehicle with a LiDAR sensor and local motion generated by an object e.g., a walking person. Thus, Inter-EM consists of a compression structure in terms of both global and local motion, and the Inter-EM’s global motion compensation technology increases the compression efficiency via a single matrix describing the global motion of points. However, this is difficult to predict with a single matrix, which causes imprecise global motion estimation since the objects in a LiDAR-based point cloud show different global motion estimates according to object characteristics such as shape and position. Therefore, this paper proposes a global motion prediction and compensation scheme that considers the characteristics of objects for efficient compression of LiDAR-based point cloud frames. The proposed global motion prediction and compensation scheme achieved maximum gain of −22.0% and average of −9.4% in terms of the Bjontegaard-Delta-rate (BD-rate), and effectively compressed the LiDAR-based sparse point cloud.

Image motion compensation technology of aerial photoelectric imaging system

Image motion compensation technology of aerial photoelectric imaging system

Real time motion compensation technology based on least square support vector machine prediction

When cameras are used in aerial photography, satellite imaging or other scenes, the motion of the observational target causes image blur. The corresponding motion compensation systems often present some response delay. Thus, we introduce effective and fast motion prediction for the target to achieve steady real-time motion compensation. We first analyze the target motion states to propose a fast and robust prediction method based on the least square support vector machine algorithm. Then, we evaluate the performance between ours and other state-of-the-art methods through experiments. Experimental results confirm that the proposed method provides a fast and robust prediction for target motion. At last, we embed our method with dual-resolution camera system to perform high-quality motion compensation effect in real time.

On Combining Fractional-Pixel Interpolation and Motion Estimation: A Cost-Effective Approach

The additional complexity of the adoption of fractional-pixel motion compensation technology arises from two aspects: fractional-pixel interpolation (FPI) and fractional-pixel motion estimation (FPME). Different from current fast algorithms, we use the internal link between FPME and FPI as a factor in considering optimization by integrally manipulating them rather than attempting to speed them up separately. In this paper, a refinement search order for FPME is proposed to satisfy the criteria of cost/performance efficiency. And then, some strategies, i.e., FPME skipping, early termination and search pattern pruning, are also given for reducing the number of search positions with negligible coding loss. We also propose a FPI algorithm to save redundant interpolation as well as reduce duplicate calculation. Experimental results show that our integrated algorithm significantly improves the overall speed of FPME and FPI. Compared with the FFPS+XFPI and CBFPS+XFPI, the proposed algorithm has already reduced the speed by a factor of 65% and 32%. Additionally, our FPI algorithm can be used to cooperate with any fast FPME algorithms to greatly reduce the computational time of FPI.