Coordinate Reference Research Articles

Robust Adaptive Contouring Control for Machine Tool Feed Drive Systems

Contouring controller design has been widely studied thus far because of its effectiveness for machine tool control. However, plant modeling errors and disturbances such as nonlinear frictions and cutting forces are little considered in existent designs. This paper presents a new contouring controller design that is robust to these unknown factors. First, a contouring controller design based on a coordinate transformation and reference signal adjustment, which has been developed by the authors, is explained. This design enables to adjust control performance of the contour error and the other error component independently to enhance the effectiveness of the contouring control. Next, assuming that upper bounds of plant modeling error and disturbance magnitudes are known, we extend this design to have robustness with respect to plant modeling errors and disturbances. Because unnecessary large values of these magnitudes deteriorate control performance, we further design an estimator of these upper bounds in real time. Comparative experiments demonstrate the effectiveness of the proposed design.

High Resolution Diffusion Tensor Atlas of the Mouse Brain

Event Abstract Back to Event High Resolution Diffusion Tensor Atlas of the Mouse Brain Yi Jiang1* and G. A. Johnson1 1 Duke University Medical Center, Center for In Vivo Microscopy, United States Introduction Eight Diffusion tensor imaging (DTI) datasets of normal adult mouse brains were acquired at 43 µm isotropic resolution by using a streamlined protocol, including specimen fixation and staining, image acquisition, reconstruction, and normalization to a common reference brain (Waxholm Space). The normalization accuracy was evaluated by measuring landmarks displacement between individual brains and the reference brain. Mean values of DTI parameters, e.g. anisotropy and diffusivity, were computed in 9 white matter (WM) structures to determine if the current protocol is able to provide consistent data and distinguish anatomical difference between WMs. Method 8 normal adult male C57BL/6 mouse brains were actively stained. T1 and T2*, one b0, and 6 diffusion-weighted images were acquired on a 9.4 T magnet using a spin-echo sequence at 43 µm resolution. The T1 and T2* images were used with DiffeoMap to register each individual brain to a reference brain, using rigid transformation, affine transformation, and two-channel LDDMM. The transformation matrix was then applied to properly map and reorient the diffusion tensors. Eigenvalues, where the primary eigenvalue is axial diffusivity (AD), eigenvectors, fractional anisotropy (FA), radial diffusivity (RD), and color-coded orientation map of the primary eigenvector (ev0) were calculated in DTIStudio. 80 landmarks were manually selected on each brain and the reference brain. The landmarks on individual brains were mapped on to the reference coordinate with the corresponding transformation matrix. Displacements between landmarks mapped from individual brains and landmarks of the reference brain were measured to quantify registration accuracy. Nine WM structures including lateral lemniscus, anterior commissure, cerebral peduncle, internal capsule, optic tract, fimbria, corpus callosum, fornix, and spinal trigeminal tract were manually defined in the reference brain. The averaged values of FA, AD, RD, and angular difference of ev0 were calculated in the 9 WMs in each individual brain. One-way ANOVA and post hoc Tukey-Kramer tests were used to examine regional variations of each parameter across 8 brains and across 9 WMs. To decide if the quality of manual delineation has any influence on the statistical findings, a white matter probability atlas (WMPA) was constructed by averaging the 8 thresholded FA maps of individual brains. The same statistical tests were applied on the core regions (e.g., with WM probability of 0.5, 0.625, 0.75, 0.875, or 1) of the manually defined WMs. Results The figure shows group average of FA, AD, RD and colormap of 8 brains providing visual feedback on the normalization quality. Mean displacement of the 640 landmarks is only 1.5±1.0 pixels. The table lists p-values of the ANOVA test of FA, AD, RD, and ev0 across 8 brains or across 9 WMs. No significant difference was found across the 8 brains for any parameter. In contrast, there exists significant difference across the 9 WMs for all parameters. Subsequent Tukey-Kramer tests provide additional information, such as the lateral lemniscus was found to have significantly lowest anisotropy, while the cerebral peduncle exhibits the highest anisotropy. Analysis of core regions of WMs with probability level of 0.5, 0.625, 0.75, 0.875 or 1 does not change the statistical findings (data not shown). Conclusions This protocol is able to acquire high-resolution DTI data of mouse brain in a robust and repeatable fashion, allowing us to normalize individual brains onto a common reference with high accuracy, lending validity to atlas-based representation of DTI parameters. It will serve as a foundation to quantitatively study mouse brain integrity and white matter architecture, at what we believe to be the highest spatial resolution yet attained. Acknowledgement All work performed at the Duke CIVM, an NCRR National Resource (P41 RR005959).

Representation of coordinate reference systems for the rodent brain in the INCF Digital Atlasing Infrastructure

Representation of coordinate reference systems for the rodent brain in the INCF Digital Atlasing Infrastructure

Transformation method of exterior orientation angular elements obtained via position and orientation system under Gauss-Kruger projection coordinate system

Data obtained via airborne position and orientation system (POS) is in WGS 84 global geocentric reference frame, while the national coordinate reference system for topographic mapping in China is generally Gauss-Kruger projection coordinate system. Therefore, data obtained via a POS must be transformed to national coordinate system. Owing to the effects of earth curvature and meridian deviation, there are some errors in the process of angle transformation from roll, pitch, and heading (Φ,Θ,Ψ) obtained directly via a POS to the attitude angles of images (φ,ω,κ) needed in photogrammetry. On the basis of effect theories of earth curvature and meridian deviation on exterior orientation angular elements of images, a method using a compensation matrix to correct the transformation errors from attitude angles obtained via the POS to exterior orientation angular elements of images is proposed in this paper. Moreover, the rigorous formula of the compensation matrix is deduced. Two sets of actual data obtained via a POS AV 510, which are different in scale and terrain, are selected and used to perform experiments. The empirical results not only indicate that the compensation matrix proposed in this paper is correct and practical but also show that transformation accuracy of exterior orientation angular elements obtained via the POS based on compensation matrix is relevant to the selection of vertical axis (a projection of central meridian) of Gauss-Kruger projection coordinate system; the proper vertical axis should be the Gauss-Kruger projection of the central meridian of projection zone in which the survey area locates. However, the transformation accuracy of exterior orientation angular elements is irrelevant to the choice of origin of coordinate system; it is appropriate that the origin of coordinate system locates at the center point of the survey area. Moreover, transformation accuracy of exterior orientation angular elements achieved based on the compensation matrix deduced in this paper is higher than that obtained via the existing POS processing software.

A Terrestrial Reference Frame (TRF), coordinates and velocities for South American stations: contributions to Central Andes geodynamics

Abstract. Satellite positioning systems allow the fixing of the location of a point on the Earth's surface with very good precision and accuracy. To do this, however, it is necessary to determine the point coordinates taking account the reference system and the movements that affect them because of tectonic plate movements. These reference systems are materialized by a significant number of continuous measurement stations in South America. In SIRGAS (Sistema de Referencia Geocéntrico para las Américas), there are four Analysis Centers that process the data collected from satellites of the Global Navigation Satellite Systems (GNSS), with the primary purpose to maintain the international terrestrial reference frame through calculation of the coordinates and velocities of the continuous GNSS stations of the SIRGAS-CON Network. In this work, we demonstrate the quality of the solutions from CIMA, one of the SIRGAS official processing centers operating in Mendoza, Argentina, in comparison with other South American processing centers. The importance of precise calculations of coordinates and velocities in a global frame is also shown. Finally, we give estimations of velocities from stations located within deformation zones in the Central Andes.

Studies of the Earth's center of mass periodical movements

At present the Earth reference coordinate frame ITRF is realized on the base of space geodesy observations in strictly secular sense with purely linear temporal changes (velocities) without any conventional models. These linear changes include primarily non modeled geophysical motions, mostly of tectonic origin. In the base of all space geodesy techniques (except of VLBI), there are precise orbits of the observable satellites, which are moving under the influence of the Earth gravity field around of the entire Earth’s center-of-mass (CM). To keep the convention of the coincidence of the terrestrial coordinate system origin with the entire Earth center-of-mass, the first harmonics (C1,1, S1,1, C1,0) of the gravity field models, used for orbital calculations, are equated to zero. Studies of the ITRF precision and stability, carried out at the different research centers, INASAN included, show that origin of the coordinate system (Geocenter) is moving relatively to the center of mass. Besides the main geophysical effects: atmosphere pressure, oceanic tides and currents, ice melting, have been taken into consideration. The annual and semiannual amplitudes of the geocenter variations are not the same for different types of measurements and fluctuate in the interval 1–23 mm for all three components of the position vector. And Z-component is always 2–3 times more than planar components. The absolute scale of the network is determined with the accuracy around of 0.5 · 10−13, that is equivalent 3 mm in the station height. The further improvement of the ITRF accuracy and stability is possible with the use of more dense and equally distributed tracking networks, equipped with the different types of modern instruments, allowed to minimize systematic errors, characteristic for every usable technique. In this connection the International Association of Geodesy arrived to a decision on the development of the Global Geodetic Observing System (GGOS), which will consist of about 40 permanent ground tracking sites, space segment of special research satellites and centers of merging, storage and analyses of the data.

Impact of modulation on CMBB-mode polarization experiments

We investigate the impact of both slow and fast polarization modulation strategies on the science return of upcoming ground-based experiments aimed at measuring the B-mode polarization of the CMB. Using simulations of the Clover experiment, we compare the ability of modulated and un-modulated observations to recover the signature of gravitational waves in the polarized CMB sky in the presence of a number of anticipated systematic effects. The general expectations that fast modulation is helpful in mitigating low-frequency detector noise, and that the additional redundancy in the projection of the instrument's polarization sensitivity directions onto the sky when modulating reduces the impact of instrumental polarization, are borne out by our simulations. Neither low-frequency polarized atmospheric fluctuations nor systematic errors in the polarization sensitivity directions are mitigated by modulation. Additionally, we find no significant reduction in the effect of pointing errors by modulation. For a Clover-like experiment, pointing jitter should be negligible but any systematic mis-calibration of the polarization coordinate reference system results in significant E-B mixing on all angular scales and will require careful control. We also stress the importance of combining data from multiple detectors in order to remove the effects of common-mode systematics (such as 1/f atmospheric noise) on the measured polarization signal. Finally we compare the performance of our simulated experiment with the predicted performance from a Fisher analysis. We find good agreement between the Fisher predictions and the simulations except for the very largest scales where the power spectrum estimator we have used introduces additional variance to the B-mode signal recovered from our simulations.

DSM과 다시점 거리영상의 3차원 등록을 이용한 무인이동차량의 위치 추정: 가상환경에서의 적용

A computer vision technique of estimating the location of an unmanned ground vehicle is proposed. Identifying the location of the unmaned vehicle is very important task for automatic navigation of the vehicle. Conventional positioning sensors may fail to work properly in some real situations due to internal and external interferences. Given a DSM(Digital Surface Map), location of the vehicle can be estimated by the registration of the DSM and multiview range images obtained at the vehicle. Registration of the DSM and range images yields the 3D transformation from the coordinates of the range sensor to the reference coordinates of the DSM. To estimate the vehicle position, we first register a range image to the DSM coarsely and then refine the result. For coarse registration, we employ a fast random sample matching method. After the initial position is estimated and refined, all subsequent range images are registered by applying a pair-wise registration technique between range images. To reduce the accumulation error of pair-wise registration, we periodically refine the registration between range images and the DSM. Virtual environment is established to perform several experiments using a virtual vehicle. Range images are created based on the DSM by modeling a real 3D sensor. The vehicle moves along three different path while acquiring range images. Experimental results show that registration error is about under 1.3m in average.

Quantum chemical calculations for understanding and predicting toxicity. I. Ab initioMODPOT/VRDDO calculations and electrostatic molecular potential contour maps of organophosphorus anticholinesterases

To demonstrate the feasibility of quantum chemical and other theoretical techniques in the understanding and correlation and then in the prediction of toxicity of a specific class of compounds, the organophosphorus acetylcholinesterase (AChE) inhibitors were chosen since these have relatively clear-cut one-dose acute lethal toxicity, both LD50, and ED50 for the triggering event inhibition of AChE, to serve as well-defined end points. It was possible to identify particular quantum chemical requisites which are related to and predictive of the toxic effects of these molecules. Ab initio calculations were carried out on a number of organophosphorus compounds using our own programs which incorporate a number of desirable options for ab initio calculations on large molecules, including ab initio effective core model potentials (MODPOT), which permit calculations of valence electrons only explicitly, yet accurately, and a charge-conserving integral prescreening evaluation (which we named VRDDO—variable retention of diatomic differential overlap) especially effective for spatially extended molecules. Ab initio calculations were carried out for the two optical isomers of GB: These isomers differ in their toxicities. From the wavefunctions of the optical isomers of GB (calculated relative to internal body-fixed coordinates) the electrostatic molecular potential contour maps (relative to the same absolute space-fixed reference coordinates) were generated in three dimensions around each molecule. These maps indicate vividly the differing stereoelectronic requisites for the different optical isomers and suggest the basis for the difference in their in vivo toxicities. These maps form three-dimensional stereoelectronic holograms and can even be used for reverse image holography to ascertain if new even hypothetical molecules fulfill the requisites. This is related to the first step in the inhibition of AChE, complex formation of the organophosphorus compound with AChE.

First-principles design of nanomachines

Learning from nature's amazing molecular machines, globular proteins, we present a framework for the predictive design of nanomachines. We show that the crucial ingredients for a chain molecule to behave as a machine are its inherent anisotropy and the coupling between the local Frenet coordinate reference frames of nearby monomers. We demonstrate that, even in the absence of heterogeneity, protein-like behavior is obtained for a simple chain molecule made up of just 30 hard spheres. This chain spontaneously switches between 2 distinct geometries, a single helix and a dual helix, merely because of thermal fluctuations.

Simulating Acceleration From Stereophotogrammetry For Medical Device Design

When designing a medical device based on lightweight accelerometers, the designer is faced with a number of questions in order to maximize performance while minimizing cost and complexity: Where should the inertial unit be located? How many units are required? How is performance affected if the unit is not correctly located during donning? One way to answer these questions is to use position data from a single trial, captured with a nonportable measurement system (e.g., stereophotogrammetry) to simulate measurements from multiple accelerometers at different locations on the body. In this paper, we undertake a thorough investigation into the applicability of these simulated acceleration signals via a series of interdependent experiments of increasing generality. We measured the dynamics of a reference coordinate frame using stereophotogrammetry over a number of trials. These dynamics were then used to simulate several "virtual" accelerometers at different points on the body segment. We then compared the simulated signals with those directly measured to evaluate the error under a number of conditions. Finally, we demonstrated an example of how simulated signals can be employed in a system design application. In the best case, we may expect an error of 0.028 m/s2 between a derived virtual signal and that directly measured by an accelerometer. In practice, however, using centripetal and tangential acceleration terms (that are poorly estimated) results in an error that is an order of magnitude greater than the baseline. Furthermore, nonrigidity of the limb can increase error dramatically, although the effects can be reduced considerably via careful modeling. We conclude that using simulated signals has definite benefits when an appropriate model of the body segment is applied.

Theoretical study on guided wave propagation in (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (x = 0.29 and 0.33) single crystal plates

The propagation of guided waves in free standing (1 − x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 [PMN–xPT] (x = 0.29 or 0.33) single crystal plates has been studied theoretically. The polar directions are in the ⟨111⟩ family directions of the cubic reference coordinates but the crystals are being polarized along [0 0 1]c, [0 1 1]c and [1 1 1]c of the cubic reference directions so that the effective microscopic symmetries are 4mm, mm2 and 3m, respectively. Multiple mode couplings appear in the dispersion curves for both the symmetric and the antisymmetric Lamb and shear horizontal modes. The velocities of most guided waves decrease rapidly with frequency. Then, after passing a minimum, they begin to increase with frequency and eventually saturate to the shear wave velocity vsz (or v1 = 3507 m s−1 for [1 1 1]c polarized sample). For a [1 1 1]c polarized single domain PMN–0.33PT sample, the S1 mode instead of the S0 mode approaches the Rayleigh velocity vR at high frequencies.

An Intraoperative Brain Shift Monitor Using Shear Mode Transcranial Ultrasound

Various methods of intraoperative structural monitoring during neurosurgery are used to localize lesions after brain shift and to guide surgically introduced probes such as biopsy needles or stimulation electrodes. With its high temporal resolution, portability, and nonionizing mode of radiation, ultrasound has potential advantages over other existing imaging modalities for intraoperative monitoring, yet ultrasound is rarely used during neurosurgery largely because of the craniotomy requirement to achieve sufficiently useful signals. Prompted by results from recent studies on transcranial ultrasound, a prototype device that aims to use the shear mode of transcranial ultrasound transmission for intraoperative monitoring was designed, constructed, and tested with 10 human participants. Magnetic resonance images were then obtained with the device spatially registered to the magnetic resonance imaging (MRI) reference coordinates. Peaks in both the ultrasound and MRI signals were identified and analyzed for both spatial localization and signal-to-noise ratio (SNR). The first results aimed toward validating the prototype device with MRI showed an excellent correlation (n = 38; R(2) = 0.9962) between the structural localization abilities of the two modalities. In addition, the overall SNR of the ultrasound backscatter signals (n = 38; SNR = 25.4 +/- 5.2 dB, mean +/- SD) was statistically equivalent to that of the MRI data (n = 38; SNR = 22.5 +/- 4.8 dB). A statistically significant correlation of localized intracranial structures between intraoperative transcranial ultrasound monitoring and MRI data was achieved with 10 human participants. We have shown and validated a prototype device incorporating transcranial shear mode ultrasound for clinical monitoring applications.

A13 2リンクフレキシブルロボットアームの手先空間制御に関する基礎研究(OS3 ロボットのダイナミクスと制御1)

In most studies on flexible robot arm, the controller is designed in joint space, besides the task for robot arm is described in reference coordinate frame. In this paper, basic research of end point position control for two links flexible robot arm is dealt with. The nonlinearity of the arm is canceled by using a nonlinear compensator designed by a dissolve motion acceleration control (DMAC). The linearlized model is controlled by a PID controller. The robustness of the obtained controller are verified by the simulation and the control experiment.

Some issues and insights for gravity and magnetic modelling at the region to continent scale

The form of the Earth is much closer to a sphere than a flat slab, so why is gravity and magnetic modelling almost exclusively carried out within a flat Earth or Cartesian framework? The use of a Cartesian coordinate system can be attributed in part to the absence of alternatives in the commercial modelling and visualisation software packages and the need for additional computational resources if modelling is carried out in a spherical or ellipsoidal reference system. These are not sufficiently good reasons, however, to blindly continue with this practice. Gravity modelling is a particularly widespread activity, being used for basic gravity data processing (e.g., Bouguer and terrain corrections - e.g., LaFehr, 1991a, 1991b, 1998; Talwani, 1998; Hinze et al, 2005), geodesy applications (e.g., geoid calculations), and geological interpretation. To what degree are the outcomes of these activities affected by the choice of Earth representation? In the exploration geophysics community, there is a standard answer to the question ?when do curvature effects become significant? which is ?when the models are larger than 166.7 km in horizontal extent?. This criterion can be traced back to Hayford and Bowie (1912). What was the basis for choosing this distance? Is this a criterion that can be applied to all modelling applications or just the original application of Hayford and Bowie (1912)? Although there is general acknowledgment that the curvature of the Earth is important when performing gravity or magnetic modelling of long traverses or large regions, there are few studies of the errors involved if a Cartesian (or rectangular) coordinate reference system is used. Examples that demonstrate the magnitude of curvature effects on gravity response can be found in Hayford and Bowie (1912), Takin and Talwani (1966), Johnson and Litehiser (1972), Qureshi (1976), Miku?ka et al. (2006), and Cavsak (2008). In the following, results of simple calculations for a regular mesh of prismatic elements are presented to quantify the differences in vertical gravity and vertical gravity gradient response for equivalent representations of source elements in Cartesian or spherical coordinate reference systems. It is noted that outcomes for vertical gravity gradient response are the same as those that would be obtained for total magnetic intensity response (TMI). Although this work is based on models comprised of a regular array of prismatic mesh elements, the outcomes can be related to those that would be obtained for models based on arbitrary 3D polyhedra. There are clear extensions of methodology that would allow modellers to estimate the significance of curvature effects for any specific application. This will help to answer the question that is prompted by Figure 1, i.e., ?How significant are the differences if I carry out gravity or magnetic modelling for a portion of the Earth using a Cartesian framework rather than a spherical framework??

Objective assessment of deformable image registration in radiotherapy: A multi‐institution study

The looming potential of deformable alignment tools to play an integral role in adaptive radiotherapy suggests a need for objective assessment of these complex algorithms. Previous studies in this area are based on the ability of alignment to reproduce analytically generated deformations applied to sample image data, or use of contours or bifurcations as ground truth for evaluation of alignment accuracy. In this study, a deformable phantom was embedded with 48 small plastic markers, placed in regions varying from high contrast to roughly uniform regional intensity, and small to large regional discontinuities in movement. CT volumes of this phantom were acquired at different deformation states. After manual localization of marker coordinates, images were edited to remove the markers. The resulting image volumes were sent to five collaborating institutions, each of which has developed previously published deformable alignment tools routinely in use. Alignments were done, and applied to the list of reference coordinates at the inhale state. The transformed coordinates were compared to the actual marker locations at exhale. A total of eight alignment techniques were tested from the six institutions. All algorithms performed generally well, as compared to previous publications. Average errors in predicted location ranged from 1.5 to 3.9 mm, depending on technique. No algorithm was uniformly accurate across all regions of the phantom, with maximum errors ranging from 5.1 to 15.4 mm. Larger errors were seen in regions near significant shape changes, as well as areas with uniform contrast but large local motion discontinuity. Although reasonable accuracy was achieved overall, the variation of error in different regions suggests caution in globally accepting the results from deformable alignment.

유비쿼터스 모바일 로봇의 강인한 위치 추정 기법

A robust position sensing system is proposed in this paper for a ubiquitous mobile robot which moves indoors as well as outdoors. The Differential GPS (DGPS) which has a position estimation error of less than 5 m is a general solution when the mobile robot is moving outdoor, while an active beacon system (ABS) with embedded ultrasonic sensors is reliable as an indoor positioning system. The switching from the outdoor to indoor or vice versa causes unstable measurements on account of the reference coordinates and algorithm changes. To minimize the switching time in the position estimation and to stabilize the measurement, a robust position sensing system is proposed. In the system, to minimize the switching delay, the door positions are stored and updated in a database. Using the database, the approaching status of the mobile robot from indoor to outdoor or vice versa has been checked and the switching conditions are prepared before the mobile robot actually moves out or moves into the door. The reliability and accuracy of the robust positioning system based on DGPS and ABS are verified and demonstrated through the real experiments using a mobile robot prepared for this research.

Treatment Margin Following Anatomical Registration with CBCT in Patients with Prostate Cancer

Treatment Margin Following Anatomical Registration with CBCT in Patients with Prostate Cancer

보정된 카메라를 이용한 표면영상유속계의 좌표변환방법

표면영상유속계(SIV)는 영상 처리 기술을 이용하여 수표면의 유속을 측정하는 장비이다. 표면영상유속계는 하천의 유속을 매우 간편하게 측정할 수 있도록 한다. 그러나, 표면영상유속계를 이용하여 유량을 산정하고자 할 경우, 하천 표면의 평면 측량 자료와 하천의 단면 측량 자료가 반드시 필요하다. 이 때문에 표면영상유속계의 간편성과 유용성에도 불구하고, 이용자들이 쉽게 이용하기 어렵다는 그릇된 인식을 줄 수 있다. 만일 효율적이고 간편하게 하천의 평면을 추정할 수 있다면, 표면영상유속계를 마치 일반적인 프로펠러 유속계처럼 쉽게 이용할 수 있을 것이며, 그 적용성도 크게 증진될 것이다. 이 연구는 보정된 카메라를 이용하여 실제의 평면 좌표(물리 좌표)를 추정하는 방법에 대한 것이다. 이 방법을 이용하면 유속장을 추정하는 과정을 반자동화할 수 있다. 보정된 카메라에서 평면 좌표를 산정하기 위해 사진 측량학적 기법을 채택하였다. 이 기법들은 컴퓨터 시각 분야에서 오랜 동안 연구되어 온 것이다. 이 기법을 표면영상유속계에 적용하여 사영 변환을 위한 참조점들의 좌표를 구할 수 있다. 이를 통해 참조점 측량에 대한 번거로운 과정을 생략할 수 있다. 개발된 방법을 실제 적용해 본 결과는 오차를 무시할 수 있을 정도임을 입증하였다. Surface Image Velocimetry (SIV) is an instrument to measure water surface velocity by using image processing techniques. It gives us one of the easiest ways to measure water velocity. However, since it requires a set of plane survey data to estimate the velocity, it may give us some kind of misconcept that its usage would be difficult or cumbersome in spite of its handiness. If it has a feature that can estimate the plane survey data easily, it may be treated as like one of the conventional propeller velocimetries and its applicability would be improved so high. The present study is to propose a method to estimate the plane geometry of the physical coordinate with a calibrated camera. With the feature we can half-automatize the estimating procedure for the whole water velocity field. Photogrammetric technique to calculate the plane coordinates of the reference points with a calibrated camera was studied, which has originally studied for long time in the field of computer vision. By applying this technique to SIV, it is possible to estimate the location of reference coordinates for projective transform without plane survey. With this procedure the cumbersome plane survey for the reference points is omitted. One example application of the developed method showed fairly good results with insignificant errors.

Moving-Object Tracking with In-Vehicle Multi-Laser Range Sensors

This paper presents a method for moving-object tracking with in-vehicle 2D laser range sensor (LRS) in a cluttered environment. A sensing area of one LRS is limited in orientation, and hence the mobile robot is equipped with multi-LRSs for omnidirectional sensing. Since each LRS takes the laser image on its own local coordinate frame, the laser image is mapped onto a reference coordinate frame so that the object tracking can be achieved by cooperation of multi-LRSs. For mapping the coordinate frames of multi-LRSs are calibrated, that is, the relative positions and orientations of the multi-LRSs are estimated. The calibration is based on Kalman filter and chi-hypothesis testing. Moving-object tracking is achieved by two steps: detection and tracking. Each LRS finds moving objects from its own laser image via a heuristic rule and an occupancy grid based method. It tracks the moving objects via Kalman filter and the assignment algorithm based data association. When the moving objects exist in the overlapped sensing areas of the LRSs, these LRSs exchange the tracking data and fuse them in a decentralized manner. A rule based track management is embedded into the tracking system in order to enhance the tracking performance. The experimental result of three walking-people tracking in an indoor environment validates the proposed method.