Real-time Navigation System Research Articles

One Kind of Data Acquisition System Used in PC104 Embedded Navigation Computer

In order to meet requirements of real-time dynamic navigation system, one multi-channels synchronization data acquisition system was designed based on PC104 bus. It can achieve simultaneous sampling of multiple channels data in one conversion cycle of ADC. The logic control is performed by FPGA, FIFO integrated by FPGA is used as buffer, so we can use resources of FPGA in large. At the same time, this design simplified the hardware circuit and improved circuit configuration flexibility. Using interrupt mode to read data into the FIFO, so it enhanced the data acquisition speed and reduced the burden on the navigation computer. Tests proved this system is efficient and feasible.

Stereo-Based Autonomous Navigation and Obstacle Avoidance

This paper presents a stereo vision-based autonomous navigation system using a GPS and a modified version of the VFH algorithm. In order to obtain a high-accuracy disparity map and meet the time constraints of the real time navigation system, this work proposes the use of a semi-global stereo method. By not suffering the same issues of the regularly used local stereo methods, the employed stereo technique enables the generation of a highly dense, efficient, and accurate disparity map. Obstacles are detected using a method that checks for relative slopes and heights differences. Experimental tests using an electric vehicle in an urban environment were performed to validate the proposed approach.

Real-Time Navigation for a Humanoid Robot Using Particle Filter

This paper presents a practical real-time visual navigation system, including a vision system, a particle filter (PF) based localization system, and a path planning system, for humanoid robots in an indoor environment. A neural network (NN) converter system is used to solve the image distortion problem. The monocular vision system detects objects of interest in the scene, calculating their position in the image, and converting the position in the image to real world coordinates. The PF localization system estimates the current position by the robot’s motion model and corrects the estimated position by using feedback from the data gathered by the vision system. The path planning system determines the next motion based on the result of the localization system. This paper uses a tree-like path planning method which not only guides the robot to the destination but also avoids obstacles at the same time. The navigation method allows a user to assign several different target destinations to the robot simultaneously. The proposed method is implemented on a humanoid robot “ROBOTIS DARwIn-OP”, an open platform humanoid robot. The effectiveness of the system is demonstrated in an empirical evaluation.

Development of One-to-One Shortest Path Algorithm Based on Link Flow Speeds on Urban Networks

Finding shortest paths on time dependent networks is an important task for scheduling and routing plan and real-time navigation system in ITS. In this research, one-to-one time dependent shortest path algorithms based on link flow speeds on urban networks are proposed. For this work, first we select three general shortest path algorithms such as Graph growth algorithm with two queues, Dijkstra`s algorithm with approximate buckets and Dijkstra`s algorithm with double buckets. These algorithms were developed to compute shortest distance paths from one node to all nodes in a network and have proven to be fast and efficient algorithms in real networks. These algorithms are extended to compute a time dependent shortest path from an origin node to a destination node in real urban networks. Three extended algorithms are implemented on a data set from real urban networks to test and evaluate three algorithms. A data set consists of 4 urban street networks for Anaheim, CA, Baltimore, MD, Chicago, IL, and Philadelphia, PA. Based on the computational results, among the three algorithms for TDSP, the extended Dijkstra`s algorithm with double buckets is recommended to solve one-to-one time dependent shortest path for urban street networks.

Next generation distal locking for intramedullary nails using an electromagnetic X-ray-radiation-free real-time navigation system

Distal locking marks one challenging step during intramedullary nailing that can lead to an increased irradiation and prolonged operation times. The aim of this study was to evaluate the reliability and efficacy of an X-ray-radiation-free real-time navigation system for distal locking procedures. A prospective randomized cadaver study with 50 standard free-hand fluoroscopic-guided and 50 electromagnetic-guided distal locking procedures was performed. All procedures were timed using a stopwatch. Intraoperative fluoroscopy exposure time and absorbed radiation dose (mGy) readings were documented. All tibial nails were locked with two mediolateral and one anteroposterior screw. Successful distal locking was accomplished once correct placement of all three screws was confirmed. Successful distal locking was achieved in 98 cases. No complications were encountered using the electromagnetic navigation system. Eight complications arose during free-hand fluoroscopic distal locking. Undetected secondary drill slippage on the ipsilateral cortex accounted for most problems followed by undetected intradrilling misdirection causing a fissural fracture of the contralateral cortex while screw insertion in one case. Compared with the free-hand fluoroscopic technique, electromagnetically navigated distal locking provides a median time benefit of 244 seconds without using ionizing radiation. Compared with the standard free-hand fluoroscopic technique, the electromagnetic guidance system used in this study showed high reliability and was associated with less complications, took significantly less time, and used no radiation exposure for distal locking procedures. Therapeutic study, level II.

레벨 노드 선택 기반 점대점 최단경로 알고리즘

This paper suggests an algorithm that can shorten the complexity of Dijkstra algorithm that is applied to the shortest path searching in real-time GPS Navigation System into an up-to-date O(n). Dijkstra algorithm manipulates the distance of the minimum length path by visiting all the nodes from the starting node. Hence, it has one disadvantage of not being able to provide the information on the shortest path every second, in a city that consists of sophisticated roads, since it has to execute number of node minus 1. The suggested algorithm, firstly, runs by means of organizing the set of out-neighbourhood nodes at each level of the tree, and root node for departure node. It also uses a method of manipulating the distance of the minimum path of all out-neighborhoods and interior of the out-neighborhoods. On applying the suggested algorithm to two sophisticated graphs consisted of bi-direction and uni-direction, we have succeeded to obtain the distance of the minimum length path, just as same as Dijkstra algorithm. In addition, it has an effect of shortening the time taken 4 times from number of node minus1 to number of level minus 1. The satisfaction of the drivers can be increased by providing the information on shortest path of detour, every second, when occurs any rush hour or any traffic congestion due to car accident, by applying this suggested algorithm to the real-time GPS system.

Precision spacecraft navigation using a low-cost GPS receiver

Within the PROBA-2 microsatellite mission, a miniaturized single-frequency GPS receiver based on commercial-off-the-shelf (COTS) technology is employed for onboard navigation and timing. A rapid electronic fuse protects against destructive single-event latch-ups (SEL) and enables a quasi-continuous receiver operation despite the inherent sensitivity to space radiation. While limited to single-frequency C/A-code tracking with a narrow-band frontend, the receiver is able to provide precision navigation services through processing of raw GPS measurements on ground as well as a built-in real-time navigation system. In both cases, ionospheric path delays are eliminated through a combination of L1 pseudorange and carrier phase measurements, which also offers a factor-of-two noise reduction relative to code-only processing. By comparison with satellite laser ranging (SLR) measurements, a 0.3-m (3D rms) accuracy is demonstrated for the PROBA-2 reduced dynamic orbit determinations using post-processed GPS orbit and clock products. Furthermore, the experimental onboard navigation system is shown to provide real-time position information with a 3D rms accuracy of about 1 m, which notably outperforms the specification of the Standard Positioning Service (SPS). In view of their lower hardware complexity, mass budget and power requirements as well as the reduced interference susceptibility, legacy C/A-code receivers can thus provide an attractive alternative to dual-frequency receivers even for demanding navigation applications in low Earth orbit.

Testbed for Tracking System Design

A testbed for experiments with a real time navigation system was developed and installed in St.-Petersburg State University. It contains a small helicopter with TV system and sensors. A number of problems for students are formulated that contain the input data collected from the testbed.

INVESTIGATION OF THE ESSENTIALS FOR INTEGRATING OFF-THE-SHELF INDUSTRIAL ROBOTICS IN PRECISE COMPUTER-ASSISTED SURGERY

Off-the-shelf industrial robotic technologies have achieved significant advancements in the past several decades in terms of mechanics and automation performances. We are expecting to take advantage of the industrial robots for assisting surgeons in surgeries and quick prototyping a robotic surgery system. In precise computer-assisted surgeries (CASs), such as pelvic-acetabular surgery, eye surgery, or neurosurgery, it is extremely important to position the tools accurately and precisely for surgical operations. Some of the industrial robotics arms are able to achieve good repeatability and dexterity while positioning the surgical tools. To enable the application of industrial robots in the surgical rooms, there are several other essential modules to be integrated to the robotic surgery systems, such as real-time navigation system, surgical planning system, and surgeon-guidance system. In this paper, we review the existing studies on the medical robots including the ones using industrial robots, and then investigate the essentials for using industrial robots in computer-integrated surgery.

Biopsy guided by real-time virtual navigation system using computed tomography imaging data:a phantom study

Objective To verify the feasibility and the accuracy for the biopsy of targets not visible on sonography but shown on CT in a phantom by using real-time virtual navigation system(RVS).Methods The tissue mimicking phantom,made of gel,contained 30 red spheres which were 10 mm in diameter,randomly placed.These spheres were invisible on sonography,but visible on CT.A junior operator and a senior operator performed the biopsy respectively,and each sphere was biopsied once guide by both RVS and conventional ultrasound for each operator.The red dye in the biopsied sample meant successful performance.The success rate of biopsy and the length of the red dyed sample were recorded.Results There was no statistically difference between the performance results of the two operators.The success rate and the median length of red dyed sample biopsy of RVS were respectively 96.7％ (58/60) and 7.5 mm (rang,6-9 mm) which were statistically higher and longer than that of conventional ultrasound,43.3％(26/60) and 0 mm(rang,0 - 5 mm) ( P ＜0.05).Conclusions Biopsy guided by RVS for the target invisible to ultrasound is a feasible and accuracy method,which will be a new guided method for interventional ultrasound. Key words: Ultrasonography ; Phantoms, imaging; Biopsy, needle; Real-time virtual navigation system

Visual navigation with a time-of-flight camera

This paper presents a real-time visual navigation system that uses a time-of-flight camera with no a priori knowledge of the scene. A method of combining time-of-flight and optical cameras is considered. Methods that take color and spatial information into account to increase the localization reliability are considered.

Extending MITK by a real-time online video overlay navigation system for minimally invasive surgery

The purpose of this paper is to present our extension of the MITK toolkit by a real-time navigation system for computer assisted surgery. The system was developed with laparoscopic partial nephrectomies as a first application scenario. The main goal of the application is to enable tracking of the tumor position and orientation during surgery. Our system is based on ultrasound to CT registration and electromagnetic tracking. The basic idea is to process tracking information to generate an augmented reality (AR) visualization of a tumor model in the camera image of a laparoscopic camera. Our system will enhance the surgeon’s view on the current scene and therefore facilitates higher safety during the surgery. A key intention of the development was to use only open source toolkits such as VTK, MITK and OpenCV in order to implement the desired functionality. So far we have applied our system in vitro in two phantom trials with a surgeon which yielded promising results.

Real-time finger-controlled navigation system using laser speckle patterns

We used the invariance of moving laser speckle patterns to develop a finger-controlled navigation system. Laser speckle images were captured using a commercially available image sensor. The relationships between template image size, available movement range, and a maximum correlation coefficient were derived. An essential criterion for setting the correlation coefficient threshold value was determined, and a displacement estimation algorithm was developed. A navigation system test platform and an accuracy analysis program were developed to monitor system performance related to variations in the template image size and the correlation threshold value. The experimental results suggest that the proposed design would be suitable to guide further development of finger-controlled navigation systems using laser speckle patterns.

Integrated MR‐laparoscopy system with respiratory synchronization for minimally invasive liver surgery

The laparoscope has been invaluable in minimally invasive surgery, but provides only a surface view of target tissue; therefore it is lacking internal tissue information. In combination with the laparoscope for visualizing the cross-sectional view of the tissue, MRI is superior to ultrasonography or X-ray CT, because of its high soft-tissue contrast, arbitrary slice orientation and lack of radiation properties. Thus, we propose an integrated MR-laparoscopy system with a respiratory-synchronized navigation. A transmit/receive RF coil for localized MR imaging with a 0.5 T open-MRI was mounted onto the tip of an MR-compatible laparoscope. The signal detection of the coil was examined with an excised porcine liver sample, an agar phantom and the abdominal wall of a healthy volunteer. A real-time navigation system to compensate for respiratory motion was developed, and examined with a healthy volunteer. The SNRs of the local MR images were 112, 62, and 62 in the liver sample, phantom, and volunteer. The navigation system successfully displayed the scope view, scope location and orientation, and MR images with respiratory-synchronized real time operation. The MR-imaging and synchronization function of the proposed system seemed to be helpful for laparoscopic surgery.

Development and Validation of an Open-Source Real-Time Freehand 3-Dimensional Ultrasound Navigation System for Liver Surgery with GPGPU Acceleration

To achieve longterm survival after resection of liver tumors, accurate resection margins are essential. Image guided surgery with navigational support has the potential to increase surgical accuracy significantly, thus making the operation more reliable. In this article we describe an image guided navigation system for liver surgery. Our platform uses GPU acceleration to display in real-time reconstructed 3-dimensional freehand ultrasound volumes in combination with tracked surgical instruments. We evaluated the accuracy and the performance of our system on a phantom study. The results of our study demonstrate that our image guided navigation system has the potential to introduce significant improvements in the field of liver surgery.

Improved iterative pose estimation algorithm using three-dimensional feature points

In a real-time vision navigation system, an accurate and fast convergent pose estimation algorithm is required for the video guidance sensor. The orthogonal iteration (OI) algorithm is fast and globally convergent, but its results have a large translation error at a close range, and sometimes it fails to give a correct rotation matrix when the data are severely corrupted, when using the 3-D feature points. When the rotation matrix solution in the OI algorithm has been refined, an efficient pose estimation algorithm is derived. Simulation of the improved algorithm shows that the rotation matrix is always proper, which in turn improves the accuracy of the translation vector. The noise resistance and the outlier tolerance are enhanced by using the improved algorithm. The two algorithms are applied to our experimental system for an unmanned vehicle rendezvous and docking simulation separately. The comparison experiments show that the relative distance error is less than 0.28% from 1.5 to 5 m, and the rotation angle error is within ±0.7 deg in 5 m using the improved algorithm. These are better than the results using the OI algorithm.

A real-time navigation system for laparoscopic surgery based on three-dimensional ultrasound using magneto-optic hybrid tracking configuration

Objectives In laparoscopic liver surgery, intraoperative navigation is strongly recommended. We developed a navigation system based on intraoperative ultrasound (IOUS). The purpose of this study was to evaluate the usefulness and accuracy of this system using an animate model.

REAL-TIME VISION BASED AUV NAVIGATION SYSTEM USING A COMPLEMENTARY SENSOR SUITE

This paper proposes a real-time navigation system for an AUV that takes advantage of the complementary performance of a sensor suite including a DVL, a compass, a depth sensor and altimeter sensors with a feature based motion estimator using vision. To allow for real-time performance of the vision based motion estimator a simple but fast correlation algorithm is used for feature matching. The compass and the depth sensors are used to bound the drift of the heading and depth estimations respectively. The altimeter is required in order to translate the feature displacements measured from the images into the metric displacements of the robot. While the robot must rely on DVL navigation above a certain altitude where vision is useless, DVL measurements can be complemented with higher frequency accurate motion estimates from the vision system when navigating close to the seafloor.

Therapeutic Choice for Craniofacial Venous Malformations

Even though the precise mechanisms related to venous malformation are still unclear, the clinical manifestations sometimes threaten vital signs such as mastication, airway and phonics. Our therapeutic modalities were reviewed, and their effectiveness and related complications were analyzed. Between March, 1998 and February, 2006, 11 patients (15-59 years old; average 32.4 +/- 13.60, 4 women and 7 men) with craniofacial venous malformation were included in this investigation. All cases experienced some kind of surgery at least once during clinical follow-up. Direct puncture scintigraphy with technetium-99m Sn colloid-labeled demonstrated low-flow malformations in all cases. Two cases underwent bone surgery and another two cases had static suspensions for facial nerve paralysis. Blood loss from surgery alone was 1352 +/- 1115.0 mL, simultaneous procedures yielded 400 +/- 244.9 mL blood loss and sclerotherapy alone resulted in 187 +/- 284.8 mL of blood loss (surgery alone versus sclerotherapy alone, P < 0.01). Excellent sclerotherapy cases were when the malformation was localized and the number of sclerotherapies was significantly fewer than good cases (1.3 +/- 0.58 times versus 3.6 +/- 1.15 times, excellent, good, respectively, P < 0.05). Although there are difficulties in understanding the mechanisms and multiple therapeutic interventions are required, there have been satisfactory outcomes so far and the development of better sclerosants or a real-time navigation system may benefit more precise therapeutic effects and lower morbidity.

Processing of Location-Dependent Continuous Queries on Real-Time Spatial Data: the View From Retina

In this paper, using the real-time navigation system, RETINA, as an example, we study the important design issues underlying the processing of location-dependent continuous queries, especially those requiring access to data describing the current status of a dynamic environment and possessing spatial properties. To reduce the probability of missing the arrival deadline associated witheach navigation request, we use a time-stamp with prediction scheme to model the traffic data and replicated dynamic directed graphs to organize the traffic data required for path searching and path calculation. Correctness of the best path calculations and scalability of the system are improved through an adaptive Push or Pull (APoP ) scheme to monitor the best path and traffic data in navigation. A prototype and simulation results demonstrate the effectiveness of the system.