Improve Navigation Performance Research Articles

Multi-Focal Vision and Gaze Control Improve Navigation Performance

Multi-focal vision systems comprise cameras with various fields of view and measurement accuracies. This article presents a multi-focal approach to localization and mapping of mobile robots with active vision. An implementation of the novel concept is done considering a humanoid robot navigation scenario where the robot is visually guided through a structured environment with several landmarks. Various embodiments of multi-focal vision systems are investigated and the impact on navigation performance is evaluated in comparison to a conventional mono-focal stereo set-up. The comparative studies clearly show the benefits of multi-focal vision for mobile robot navigation: flexibility to assign the different available sensors optimally in each situation, enhancement of the visible field, higher localization accuracy, and, thus, better task performance, i.e. path following behavior of the mobile robot. It is shown that multi-focal vision may strongly improve navigation performance.

Multi-focal Vision and Gaze Control Improve Navigation Performance

Multi-focal vision systems comprise cameras with various fields of view and measurement accuracies. This article presents a multi-focal approach to localization and mapping of mobile robots with active vision. An implementation of the novel concept is done considering a humanoid robot navigation scenario where the robot is visually guided through a structured environment with several landmarks. Various embodiments of multi-focal vision systems are investigated and the impact on navigation performance is evaluated in comparison to a conventional mono-focal stereo set-up. The comparative studies clearly show the benefits of multi-focal vision for mobile robot navigation: flexibility to assign the different available sensors optimally in each situation, enhancement of the visible field, higher localization accuracy, and, thus, better task performance, i.e. path following behavior of the mobile robot. It is shown that multi-focal vision may strongly improve navigation performance.

Head for the hills: The influence of environmental slant on spatial memory organization

Environmental slant is known to improve navigation performance in humans and other animals. Successful navigation relies on accurate spatial orientation and accurate spatial memory retrieval. The role of environmental slant in spatial orientation has been established, but its role in spatial memory organization is unclear. Two experiments using immersive virtual reality explored the influence of environmental slant on reference frame selection during spatial learning. Participants studied object locations on a sloped surface. When no additional environmental cues were present (Experiment 1), spatial memory retrieval was best from the studied perspective aligned with the direction of slope. When the direction of slope was placed in competition with the axis of the surrounding room (Experiment 2), spatial memory retrieval was best from the initially studied perspective. The latter finding contrasts with the results of research showing that pigeons preferentially rely on environmental slant over room shape. The findings are discussed in the context of spatial memory theory.

"Spindex": Accelerated Initial Speech Sounds Improve Navigation Performance in Auditory Menus

"Spindex": Accelerated Initial Speech Sounds Improve Navigation Performance in Auditory Menus

“Spindex”: Accelerated Initial Speech Sounds Improve Navigation Performance in Auditory Menus

Users interact with mobile devices through menus, which can include many items. Auditory menus can supplement or even replace visual menus. Unfortunately, little research has been devoted to enhancing the usability of large auditory menus. We evaluated a novel auditory menu enhancement called a “spindex” (i.e., speech index), in which brief audio cues inform the user where she is in a long menu. In the current implementation, each item in a menu is preceded by a sound based on the item's initial letter. 25 undergraduates navigated through an alphabetized contact list of 50 or 150 names. The menu was presented with text-to-speech (TTS) alone, or TTS plus spindex, and with the visual menu displayed or not. Search time was faster with the spindex-enhanced menu, especially for long lists. Subjective ratings also favored the spindex. Results are discussed in terms of theory and practical applications.

웨이블릿 임계화 기법을 이용한 INS-GPS 결합항법 시스템의 성능향상

This research have introduced wavelet signal processing technic for improving navigation signals. INS signals can be distorted with conventional pre-filtering method such as low-pass filtering by unwanted smoothing on real signals. But in this paper, wavelet thresholding method is implemented to INS signal to denoise for INS-GPS integrated system. This method reduces signal noise but not distorts the rapid varing signal. And this paper applied thresholding to INS-GPS integrated navigation system and improved navigation performance.

The stable and precise motion control for multiple mobile robots

Intelligent path planning of multiple mobile robots has been addressed in this paper. Cooperative behaviour can be achieved using several mobile robots, which require online inter-communication among themselves. In the present investigation rule-based and rule-based-neuro-fuzzy techniques are analyzed for multiple mobile robots navigation in an unknown or partially known environment. The final aims of the robots are to reach some pre-defined goals. Based upon a reference motion, direction; distances between the robots and obstacles; distances between the robots and targets; different types of rules are taken heuristically and refined later to find the steering angle. The control system combines a repelling influence related to the distance between robots and nearby obstacles and with an attracting influence between the robots and targets. Then a hybrid rule-based-neuro-fuzzy technique is analyzed to find the steering angle of the robots. Results show that the proposed rule-based-neuro-fuzzy technique can improve navigation performance in complex and unknown environments compared to this simple rule-based technique.

GPS/Galileo 통합항법알고리즘 구현 및 시각 및 좌표계차이에 따른 영향분석

Galileo 위성항법시스템은 GPS에 대응하기 위해 EU에서 구축중인 시스템으로 실험위성GIOVE-A의 테스트가 끝났으며 두 번째 테스트 위성 GIOVE-B가 발사 예정이다. GPS와 Galileo 신호 모두 이용할 경우 도심지나 숲과 같은 음영지역에서도 가시위성수의 증가로 위치해를 구할 수 있고 보다 정확한 위치해를 얻을 수 있다. GPS와 Galileo 위성항법시스템은 독자적인 시각과 좌표체계를 갖추고 있으며 항법해를 계산을 위해서 서로 다른 오차 모델을 이용한다. 본 논문에서는 각 위성항법시스템의 오차 모델과 시각 및 좌표체계의 차이에 대해서 분석하였으며 이를 바탕으로 GPS와 Galileo 통합하는 항법 알고리즘을 구현하였다. 시뮬레이션을 통하여 시각, 좌표 시스템의 불일치에 의한 항법오차를 분석하고 가시위성수와 Dilution of Precision(DOP)를 계산하여 통합항법알고리즘의 성능을 검증하였다. Galileo is the Europe's global navigation satellite system corresponding to the GPS. The GIOVE-A test experiment has been finished and the second test satellite GIOVE-B will be launched soon. The integration of GPS and Galileo lead an increase of visible satellite number. We can obtain an improved navigation performance in signal blocked area such as urban or forest. GPS and Galileo have each time-coordinate system and use the different error model to calculate the navigation solution. In this paper, we studied on GPS and Galileo channel error model and time-coordinate system. Using this result, we implement the integrated navigation algorithm. In simulation, we analyzed the navigation error caused by time and coordinate disagreement and verified performance of integrated navigation algorithm in terms of visible satellite number, DOP(Dilution of Pression) and position error.

Multi-focal Vision and Gaze Control Improve Navigation Performance

Multi-focal Vision and Gaze Control Improve Navigation Performance

The Effect of Visual Momentum on Learning Hierarchical Menu Structures in Small Displays

Navigating through menu structures to access functions and search for information on small displays in cellular phones and other handheld devices is difficult. Visual momentum is a display technique that may help users integrate information across successive displays, and thus improve navigation performance for devices with small screens. This study investigated the effects of visual momentum and menu structure on the learnability of menus on small displays. Learnability was assessed using a trials-to-mastery measure. Mastery criteria regarding search time and errors were set during a pilot study and the number of trials it took for participants to meet these criteria during the Main Experiment were recorded. It was found that providing preview information in the display did not help users learn to navigate through hierarchical menus, while providing motion in the display did help.

Desktop virtual environments: a study of navigation and age

Navigation in virtual environments on desktop systems is known to be problematic. Research into the usability of the tools presented on two-dimensional interfaces indicates that, for even relatively simple tasks, users experience some degree of frustration. As the user community broadens with an increasing range of applications and services making use of three-dimensional presentation, the usability of these interfaces becomes ever more important. In this paper, we describe the results of an experiment performed to evaluate the usability of a number of visual navigation tools and the effect for two age groups (18–45 and 46+). Results indicate that, for both age groups, the visual presentation of navigational aids improves navigation performance in terms of both time taken to complete tasks, and user satisfaction with the system. In all experimental conditions younger participants achieved better performance times, although the gap between the groups decreased when a choice of navigation aids was presented.

Navigational tools for desktop virtual environment interfaces

Desktop systems typically rely on a two-dimensional (2D) software interface and general purpose hardware (mouse, keyboard) for interaction with a three-dimensional (3D) virtual environment. These interfaces must provide all the functionality required to navigate through and interact with the virtual environment, yet research into the usability aspects of the tools presented on these software interfaces indicates that the majority of users experience some degree of frustration when using them to perform even relatively simple tasks. This paper begins with a study of usability issues for interfaces to virtual environments on desktop systems, and details a series of experiments performed to evaluate the usability of a number of navigational tools. Participants were tested on the time taken to complete a number of navigational tasks with a series of interfaces presenting different navigational tools. The tools presented were a speed control function, a you-are-here (YAH) map, a function enabling the user to mark and teleport to any location within the presented environment, and an undo function. Results indicate that the visual presentation of navigational aids improves navigation performance, in terms of the time taken to complete tasks, and also improves user satisfaction with the desktop system.

Does mental simulation of following a path improve navigation performance without vision?

We recorded the paths of subjects who walked along a memorized hexagonal route without vision, and studied the impact of previous mental simulation of this activity on how well the path could be reproduced from memory. We compared two kinds of mental simulation to actual physical practice, rest, or simple memorization of the path. The results indicated that mental simulation led to better reproduction of the global shape of a path than rest, and in fact mental simulation was as effective as actual physical practice. However, this result occurred only for ‘simple shapes’ when the lengths of the sides of the path were kept constant. Nevertheless, this level of performance was not reached when the complexity of the shape was increased by altering the lengths of sides, even when keeping constant the angles between consecutive sides. This finding indicates that the internal representation of space depends on geometric properties of the environment in which the subjects operate. Mental simulation appears to affect both a map-like and route-like representation of the environment.

Designing for Spatial Orientation in Endoscopic Environments

Disorientation or “getting lost” in colonoscopy is common experience even for expert endoscopists. This paper describes a new navigational aid display concept for colonoscopy and presents results of an experiment conducted to evaluate the usefulness of various types of spatial information for supporting navigation and spatial orientation in colonoscopy. Six combinations of 1) direction, 2) location, and 3) shape information were tested. Results show that even though the new navigational aid display concept did not improve navigation performance, spatial orientation error and workload were reduced significantly. This new navigational aid display which provides shape combined with location and direction information in a perspective view and in real time is a useful tool for colonoscopy.

Infant behavior during impossible events without occlusion

Hippocampal rhythms are important for spatial navigation. This study examined whether gender differences in human navigation performance are associated with differences in hippocampal rhythms. We measured brain activities in males and females with whole-head magnetoencephalography (MEG), while they performed a virtual Morris water maze task. Behavioural results showed clear gender differences: males were significantly faster than females; unlike males, females did not show improved navigation performance in a familiar vs. new environment. MEG results showed that the magnitudes of right hippocampal/parahippocampal theta rhythm were similar between the two groups during navigation in a new environment; however, unlike males who exhibited a significant decrease in right hippocampal/parahippocampal theta power in the familiar environment shown before, females showed no change. This result may suggest faster environmental learning in males vs. females. After navigating in the new environment during the inter-trial (ITI) rest periods, males showed significantly higher right hippocampal/parahippocampal high-gamma power than females, suggesting greater consolidation in males. Moreover, right hippocampal/parahippocampal theta power during navigation correlated with navigation performance in both genders; high-gamma power during the ITI was correlated with navigation performance only in males. These associations may provide further support for the functional importance of theta and high-gamma rhythms in navigation. Overall, this study provides new insights into the neurophysiological mechanisms underlying gender differences in spatial navigation.

The Effects of Spatial Scanning Ability, Perceptual Speed, Age, and Navigation Aid on Navigation Performance

This study investigated the relationship among spatial scanning ability, perceptual speed, and navigation performance in older and younger drivers. Fifty-six drivers performed a navigation task in a part-task driving simulator using: 1) text directions, 2) a standard paper map, 3) an enlarged paper map, and 4) a turn-by-turn display. Measures included navigation error rate and decision time, and spatial scanning and perceptual speed scores. Younger drivers performed better than the older drivers in error rate and decision time, and the turn-by-turn display improved performance compared to either map. Spatial scanning ability was a stronger predictor of error rate, while perceptual speed was a stronger predictor of decision time. The results suggest that navigation aids requiring minimal spatial and perceptual processing can improve navigation performance.

O-7-104 - Image-directed neuroendoscopy

A neuro-fuzzy system architecture for behavior-based control of a mobile robot in unknown environments is presented. A neural network is used to understand environments. Its inputs are a heading angle between the robot and a specified target, and range information acquired by an array of ultrasonic sensors. The output from the neural network is a trained reference motion direction for robot navigation.The methodology of the behavior-based control approach proposed in this paper is: (1) to analyze and to decompose a complex task based on stimulus-response behavior; and (2) to quantitatively formulate each type of behavior with a simple feature by fuzzy sets and fuzzy rules as well as to coordinate conflicts and competition among multiple types of behavior by fuzzy reasoning. An advantage is that building fuzzy sets and rules for each simple-featured type of behavior is much easier than for a complex task.Based upon a reference motion direction and distances between the robot and obstacles, different types of behavior are fused by fuzzy logic to control the velocities of the two rear wheels of the robot. Simulation experiments show that the proposed neuro-fuzzy system can improve navigation performance in complex and unknown environments. In addition, this architecture is suitable for multisensor fusion and integration.

A neuro-fuzzy system architecture for behavior-based control of a mobile robot in unknown environments

A neuro-fuzzy system architecture for behavior-based control of a mobile robot in unknown environments is presented. A neural network is used to understand environments. Its inputs are a heading angle between the robot and a specified target, and range information acquired by an array of ultrasonic sensors. The output from the neural network is a trained reference motion direction for robot navigation. The methodology of the behavior-based control approach proposed in this paper is: (1) to analyze and to decompose a complex task based on stimulus-response behavior; and (2) to quantitatively formulate each type of behavior with a simple feature by fuzzy sets and fuzzy rules as well as to coordinate conflicts and competition among multiple types of behavior by fuzzy reasoning. An advantage is that building fuzzy sets and rules for each simple-featured type of behavior is much easier than for a complex task. Based upon a reference motion direction and distances between the robot and obstacles, different types of behavior are fused by fuzzy logic to control the velocities of the two rear wheels of the robot. Simulation experiments show that the proposed neuro-fuzzy system can improve navigation performance in complex and unknown environments. In addition, this architecture is suitable for multisensor fusion and integration.

Application of multiple model estimation to a recursive terrain height correlation system

This paper describes the results of an investigation of the performance capabilities of an extended Kalman filter (EKF)-based recursive terrain correlation system proposed for low-altitude helicopter navigation. The major disadvantage of this concept is its sensitivity to initial position error. One method for reducing this sensitivity, involves the use of multiple model estimation techniques. In the multiple model approach, a bank of identical EKF's, each of which is initialized at a different point in the a priori uncertainty basket, is employed to ensure that one filter is initialized near the true aircraft position. In this manner, the probability of filter convergence is increased substantially, leading to improved navigation performance.