Mobile visual detecting system with a catadioptric vision sensor in pipeline

Three dimensional (3D) shape reconstruction based on structured light technique is one of the most crucial and attractive techniques in the field of optical metrology and measurements due to the nature of non-contact and high-precision. Acquiring high-quality 3D shape data of objects with complex surface is an issue that is difficult to solve by single-frequency method. However, 3D shape data of objects with complex surface can be obtained only at a limited accuracy by classical multi-frequency approach. In this paper, we propose a new robust deep learning shape reconstruction (DLSR) method based on the structured light technique, where we accurately extract shape information of objects with complex surface from three fringe patterns with different frequencies. In the proposed DLSR method, the input of the network is three deformed fringe patterns, and the output is the corresponding 3D shape data. Compared with traditional approach, the DLSR method is pretty simple without using any geometric information and complicated triangulation computation. The experimental results demonstrate that the proposed DLSR method can effectively achieve robust, high-precision 3D shape reconstruction for objects with complex surface.

Three-dimensional ankle joint moments were calculated in two separate coordinate systems, from 18 healthy men during the stance phase of walking, and were then compared. The objective was to determine the extent of differences in the calculated moments between these two commonly used systems and their impact on interpretation. Video motion data were obtained using skin surface markers, and ground reaction force data were recorded from a force platform. Moments acting on the foot were calculated about three orthogonal axes, in a global coordinate system (GCS) and also in a segmental coordinate system (SCS). No differences were found for the sagittal moments. However, compared to the SCS, the GCS significantly (p < .001) overestimated the predominant invertor moment at midstance and until after heel rise. It also significantly (p < .05) underestimated the late stance evertor moment. This frontal plane discrepancy was attributed to sensitivity of the GCS to the degree of abduction of the foot. For the transverse plane, the abductor moment peaked earlier (p < .01) and was relatively smaller (p < .01) in the GCS. Variability in the transverse plane was greater for the SCS, and attributed to its sensitivity to the degree of rearfoot inversion. We conclude that the two coordinate systems result in different calculations of nonsagittal moments at the ankle joint during walking. We propose that the body-based SCS provides a more meaningful interpretation of function than the GCS and would be the preferred method in clinical research, for example where there is marked abduction of the foot.

Accurate vehicle localization technologies are significant for current onboard navigation systems and future autonomous vehicles. More specifically, positioning accuracy is expected at the submeter level. This paper presents an accurate vehicle self-localization system and evaluates the proposed system in different classes of urban environments. The developed system adopts an innovative global navigation satellite system (GNSS) positioning method as the key technique. The GNSS positioning method can improve the positioning error by reducing the effects of multipath interference and non-line-of-sight errors with the aid of a three-dimensional map. To improve positioning accuracy further, the vehicle localization system integrates the GNSS positioning technique with inertial sensors and vision sensors by considering the characteristics of each sensor. The inertial sensors represent vehicle movement with heading direction and vehicle speed. The vision sensor is used to recognize the position change relative to lane markings on the road surface. Those techniques and sensors collaborate to provide an accurate position in the global coordinate system. To verify the effectiveness and stability of the proposed system, a series of tests was conducted in one of the most challenging urban cities, Tokyo. The experiment results demonstrate that the proposed system can achieve submeter accuracy for the positioning error mean and has a 90% correct lane rate in the localization.

This paper describes accurate position control in an object coordinate system. When motion control of an industrial robot placed in a global coordinate system is taken to be in an object coordinate system, it is preferable and convenient to decide its motion by having the operator teach the robot. However, the teaching procedure requires considerable time and effort. Moreover, whenever the relative position between the robot and the object is changed, the operator needs to teach the operation again. To improve the above issue, a strategy that decides the robot motion without the teaching must be developed. This paper proposes a control strategy that does not require teaching and enables the creation of the desired motion without affecting the relative position error between the robot and the target object in object coordinate space defined by a PSD (Position Sensor Detector). In the proposed approach, the estimation algorithm of the kinetic transformation between the global and the object coordinates is introduced by using PSD output, and the error of coordinate transformation estimated by the proposed approach is compensated for in the global coordinate system. The validity of the proposed method is shown using simulations and experiments. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(3): 53–61, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20354

3D shape reconstruction is one of the most important topics in computer vision and the foundation for a wide field of application. Among various technologies, structured light is one of the most reliable techniques. However, given the field of view of projectors and cameras available in the market, the working distance needed for projectors is typically larger than that for cameras. To reduce the working distance of the projectors while covering the whole working platform, two projectors with their field of view overlapping are used to cover the working area which holds objects to be scanned. We present a spectral analysis based model for the projector-camera system, in order to find the most distinguishable colors for two projectors, and best separate the projected patterns from two projectors. The optimal values of the two colors are determined by the pattern search method in the presence of noise, which is modeled as multivariate Gaussian noise, and characterized for different input colors. The camera sensors' responses to the projector are measured after linearization with gray balance curves. After being properly calibrated, based on one image shot of the object with binary M-array patterns projected on it, the system can reconstruct a 3D shape of the object surface.

Optimal spatial orientation which minimizes bias error in model-based radiostereometric analysis for a cementless tibial baseplate is not aligned with the anatomic orientation defined by the global coordinate system.

A coupled mode equation for two nonparallel dielectric waveguides is rigorously derived from the Lorentz reciprocity theorem. the waveguides are located close to each other. Two local coordinate systems are introduced to present an intrinsic mode function. A global coordinator system also is employed to solve the coupled mode equation. As a numerical example, a coupling system consisting of two dielectric disks with different radii is analyzed. the coupled mode equation for whispering gallery modes propagating along a circumference of the disks is solved numerically in the global coordinate system. Eigenvalues of the whispering gallery modes are complex numbers because of radiation and dielectric losses. As a result, electric field distribution and the coupling coefficient around the coupling system are obtained quantitatively.

In a wide-area camera network, cameras are often placed such that their views do not overlap. Collaborative tasks such as tracking and activity analysis still require discovering the network topology including the extrinsic calibration of the cameras. This work addresses the problem of calibrating a fixed camera in a wide-area camera network in a global coordinate system so that the results can be shared across calibrations. We achieve this by using commonly available mobile devices such as smartphones. At least one mobile device takes images that overlap with a fixed camera's view and records the GPS position and 3D orientation of the device when an image is captured. These sensor measurements (including the image, GPS position, and device orientation) are fused in order to calibrate the fixed camera. This article derives a novel maximum likelihood estimation formulation for finding the most probable location and orientation of a fixed camera. This formulation is solved in a distributed manner using a consensus algorithm. We evaluate the efficacy of the proposed methodology with several simulated and real-world datasets.

Stability analysis of milling process by combining the gyroscopic effect with the symmetry and runout of the cutter

This paper presents the development of telemonitoring system for real time measurement of crucial vital signs like human temperature, heartbeat, oxygen level (SPO₂), and ECG signals. The system analyzes human signal data by using a Raspberry Pi 4 as a unit control with input devices represented by medical sensors. The doctor can see the vital information on a touchscreen and at the same time can transmit it to the ThingSpeak IoT platform for telemonitoring for storing and analyzing. To keep continuous system working, a supercharger was used instead of a normal charger and an uninterrupted power supply (UPS) to keep the medical data during electrical cutoffs. In this study, it was enhanced the system’s stability, particularly in the field and home-based monitoring. The system generated alerts upon finding abnormal values, enabling instant medical intervention. The system operated using medical sensors, which are prone to minor fluctuations due to high sensitivity. The validation was carried out through (i) comparative checks against certified reference devices for temperature, heart rate, and SpO₂ and (ii) field testing on 20 individuals with diverse ages and health conditions, streamed across four ThingSpeak channels with color-coded notifications. Recorded ranges during testing were 97.5–104.4°F for temperature, 69–130 bpm for heart rate, 88–99% for SpO₂, and 0.5–1.7 mV for ECG, demonstrating practical applicability for home and field monitoring with rapid anomaly detection. It recommend applying the Advanced Encryption Standard (AES) for future enhancements to secure sending data. AES progress was strong, symmetric encryption that helps protect the confidentiality and privacy of patient data sent over the internet. This system demonstrated a practical low-cost solution for contact-based remote healthcare monitoring with strong potential for scalability and improved security.

Optimal Byzantine-resilient convergence in uni-dimensional robot networks

We consider composite materials consisting of continuous or discontinuous fibers embedded in a matrix. Such a composite is heterogeneous, and the properties vary from point to point. On a scale that is large with respect to the fiber diameter, the fiber and matrix properties may be averaged, and the material may be treated as homogeneous. This assumption, commonly employed in macromechanical analyses of composites, is adopted here. Hence, the material is considered to be quasi-homogeneous, which implies that the properties are taken to be the same at every point. These properties are not the same as the properties of either the fiber or the matrix but are a combination of the properties of the constituents. In this chapter, equations are presented for calculating the displacements, stresses, and strains when the structure undergoes only small deformations and the material behaves in a linearly elastic manner. Continuous fiber-reinforced composite materials (and structures made of such materials) often have easily identifiable preferred directions associated with fiber orientations or symmetry planes. It is therefore convenient to employ two coordinate systems: a local coordinate system aligned, at a point, either with the fibers or with axes of symmetry, and a global coordinate system attached to a fixed reference point (Fig. 2.1). In this book the local and global Cartesian coordinate systems are designated respectively by x 1 , x 2 , x 3 and the x, y, z axes.

Multi-agent formation control is an important part of distributed perception and cooperation, which is convenient to complete various complex tasks and would be a key research direction in the future. This paper reviews the corresponding problems of formation control and the existing centralized and distributed formation control strategies. In particular, we discuss four types of distributed formation control methods based on position and displacement in the global coordinate system and distance and bearing in the nonglobal coordinate system, respectively. Moreover, this paper analyzes affine formation which does not require the global coordinate system. Combined with the current practical applications of multi-agent systems, the latest research for the formation control of the unmanned aerial vehicle (UAV), unmanned ground vehicle (UGV), unmanned surface vehicle (USV) and autonomous underwater vehicle (AUV) is given. Finally, the challenges and opportunities in this burgeoning field are discussed.

DGN95 is a static geospatial reference system, in which the change in the value of coordinates towards time as a result of tectonic plate movement and deformation of the earth’s crust, is not considered. Changes in the value of coordinates towards time need to be considered in defining a geospatial reference system for the territory of Indonesia. This is because the territory of Indonesia is located between several tectonic plates which are very dynamic and active. This area of IndoneFor this reason, SRGI2013 was born, a national coordinate system that was consistent and compatible with the global coordinate system. SRGI considers changes in coordinates based on time functions. Problems arise when the coordinates of the old pillar still use the DGN95 datum reference system. Many published maps or geodetic control network use the old coordinate system, then the mapping user has difficulty getting the conversion of coordinates change aforesaid. The purpose of this study is to produce coordinate transformation parameters to change the coordinates of the old datum (DGN95) into coordinates in the SRGI2013 datum. The results of the transformation parameters resulted are used to change coordinates that are still in the old datum. In addition to making it easier for users to transform coordinates. The coordinate transformation method used uses the 3-dimensional coordinate transformation of the Bursa-Wolf model (7 parameters) and the Affinity model (10 parameters).

We consider a distributed system consisting of autonomous mobile computing entities called robots moving in the three-dimensional space (3D-space). The robots are anonymous, oblivious, fully-synchronous and have neither any access to the global coordinate system nor any explicit communication medium. Each robot cooperates with other robots by observing the positions of other robots in its local coordinate system. One of the most fundamental agreement problems in 3D-space is the plane formation problem that requires the robots to land on a common plane, that is not predefined. This problem is not always solvable because of the impossibility of symmetry breaking. While existing results assume that the robots agree on the handedness of their local coordinate systems, we remove the assumption and consider the robots without chirality. The robots without chirality can never break the symmetry consisting of rotation symmetry and reflection symmetry. Such symmetry in 3D-space is fully described by 17 symmetry types each of which forms a group. We extend the notion of symmetricity [Suzuki and Yamashita, SIAM J. Compt. 1999] [Yamauchi et al., PODC 2016] to cover these 17 symmetry groups. Then we give a characterization of initial configurations from which the fully-synchronous robots without chirality can form a plane in terms of symmetricity.