위상천이 디지털 홀로그래피를 이용한 3차원 상대 거리 측정

For space robots accomplishing the overwhelming majority of on-orbit servicing(OOS) missions, capture of a target object is the primary task. Capture of a rotating object in orbit is an especially important and challenging task for OOS such as orbital debris removal. This paper studies the control strategy for capturing a fast rotating object by a space manipulator from a floating spacecraft in the three-dimensional space. First, in order to simulate the real contact condition as much as possible, a contact dynamics model considering the effect of the contact geometry of the capture interfaces is built. Second, the control strategy is proposed by a combination of a resolved motion rate control method and hybrid impedance control technique. The stability is proved by Lyapunov theorem. Finally, a simulation example of a 7-joint manipulator capturing a rotating target object in the unrestricted three-dimensional space is conducted to verify the feasibility and efficiency of the control strategy. In the effect of the control law, relative velocity at the contact spots is reduced, and thus the target object at an initial rotation speed of 12 deg/s (2 rpm) is captured successfully.

We propose a parallel two-step phase-shifting digital holography technique capable of instantaneous measurement of three-dimensional objects, with a view toward measurement of dynamically moving objects. The technique is based on phase-shifting interferometry. The proposed technique carries out the two-step phase-shifting method at one time and can be optically implemented by using a phase-shifting array device located in the reference beam. The array device has a periodic two-step phase distribution, and its configuration is simplified compared with that required for three-step and four-step parallel phase-shifting digital holographies. Therefore the optical system of the proposed technique is more suitable for the realization of a parallel phase-shifting digital holography system. We conduct both a numerical simulation and a preliminary experiment in the proposed technique. The results of the simulation and the experiment agree well with those of sequential phase-shifting digital holography, and results are superior to those obtained by conventional digital holography using the Fresnel transform alone. Thus the effectiveness of the proposed technique is verified.

Motion-in-depth generally refers to the movement of objects in three-dimensional space. There may be many factors that affect the anticipated effects of collision within motion-in-depth simulations. In order to elucidate the anticipated effects of collision, it is necessary to comprehensively identify the factors that will enhance these effects. In this study, we summarized the factors affecting the anticipated effects of collision within a continuous motion-in-depth simulation. Two samples were designed for each condition after evaluating various combinations of two factors each. Through an expert interview, it was found that a combination of gradual lightening with the anticipated effects of collision showed the strongest anticipated effects of collision in continuous motion-in-depth simulations.

The laser triangulation method allows non-contact scanning of objects and obtaining a three-dimensional point cloud. The measuring system consists of a camera and illuminator that allows projection of a linear laser beam on the surface of the object. The position of the laser beam is recorded on the camera matrix. Next, on the basis of the knowledge of camera angle and laser plane, coordinates of points describing the surfaces and edges of objects in three-dimensional space are determined. By calibrating the obtained data, it is possible to measure products, determining parameters such as volume, angle between planes, position of the object in space. The article discusses the issue of searching for the assumed model among the point cloud and determining its location and orientation in the container, enabling collision-free implementation of manipulation tasks with the use of an industrial robot.

Alternative use of reflection spatial light modulator in phase shifting digital Gabor holography

Digital holography enables us to reconstruct objects in three-dimensional space from holograms captured by an imaging device. For the reconstruction, we need to know the depth position of the recoded object in advance. In this study, we propose depth prediction using convolutional neural network (CNN)-based regression. In the previous researches, the depth of an object was estimated through reconstructed images at different depth positions from a hologram using a certain metric that indicates the most focused depth position; however, such a depth search is time-consuming. The CNN of the proposed method can directly predict the depth position with millimeter precision from holograms.

Phase-shifting digital holography has been used for the study of vibrating objects. The time-averaged complex amplitude of Fresnel diffracted field due to a vibrating object was obtained by using a three-step phase-shifting algorithm. Taking the inverse Fresnel transform of the complex amplitude resulted in an image of the object superimposed with Bessel fringes. The Bessel fringes are contour map of the vibration amplitude. By sinusoidally modulating the phase of the reference beam at the vibration frequency, the brightest fringe could be shifted to points of interest, thus extending the measurable range of vibration amplitude.

We demonstrate an optical sensor array which is capable of locating multiple, small fluorescent objects in three-dimensional space. Manufactured in an unmodified 130 nm CMOS process, the sensor requires no external optics or post processing. Instead, the array employs a diverse collection of angle-sensitive pixels. Each pixel has a distinct response to light intensity and incident angle. The array of pixels collectively gathers sufficient structural information to perform localization. These sensors will be useful whenever the micro-structure, rather than raw intensity, of a fluorescent sample is of interest.

Virtual objects in augmented realty (AR) often appear ”floaty”–a visual indication that augmented objects are poorly integrated into real world environments through shading. As a result, it is difficult to determine where objects are positioned in space. However, accurate depth perception is crucial for many applications in AR. I begin investigating this issue by evaluating different shading techniques for shadows, because shadows represent an important depth cue for creating a point of contact with surfaces beneath objects in three-dimensional space. As my research progresses, I hope to extend my investigation to other relative depth cues that may further resolve cue conflicts present in AR displays. My goal is to develop graphics based solutions to mitigate cue conflicts that result in perceptual uncertainty, especially in optical see-through (OST) AR displays. Resolving perceptual limitations will allow us to provide guidelines for software and hardware development of both future and current AR devices.

In these final four chapters we shall discuss some relatively recent developments in the representation of objects in three-dimensional space. We take a different approach from previous chapters where we considered the polygonal mesh. There the basic idea was to use polygonal facets that approximate to a surface, and then to project that approximation ultimately onto the window/viewport, where a representation of a three-dimensional scene is drawn. With the analytic approach we do just the opposite: we give each surface (and by extension its inside and outside) an exact representation as a combination of primitive (mathematical) objects, and we approximate only during the display stage. Nevertheless, in common with the polygonal mesh approach, we will be using the concepts of SETUP and ACTUAL positions relative to the ABSOLUTE co-ordinate system for defining geometrical objects, of the OBSERVED position relative to the OBSERVER system for placing these objects relative to an observer.

Echolocation is the process by which an organism projects acoustic signals in order to obtain a sense of its surroundings from the echoes it receives. In a general sense, any animal with a capability to hear can echolocate by emitting sounds and listening to the echoes. A person in an empty room can gain an idea of the size and shape of the room by emitting sounds and listening to the echoes from the different walls. However, in this chapter echolocation is used in a more specific sense in which an animal has a very specialized capability to determine the presence of objects considerably smaller than itself, discriminate between various objects, recognize specific objects, and localize objects in three-dimensional space (determining range and azimuth). Dolphins and bats have this specialized capability of echolocation.KeywordsBottlenose DolphinTarget StrengthHarbor PorpoiseSource LevelBeluga WhaleThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The article presents some results of research aimed at the design of human-machine interfaces,taking into account the multimodal nature of human perception, for use in the on-boardequipment of an aircraft. In particular, we are talking about the possibility of a wider use of audiochannels for input and output of information. The advantages of sound interfaces in relation tovisual and tactile ones are, first of all, in the absence of the need for directed attention of the pilot,in the ability to create auditory objects in three-dimensional space and indicate the direction toseveral different objects at the same time. In the experiments, the possibilities of spatial separationof speech information flows in an aircraft intercom in situations where the level of interferencesignificantly exceeded the level of the target speech message were tested. The indicators of targetmessage recognition were evaluated in the presence of two types of sound interference: the sound ofanother speech message and the noise of an aircraft engine. The results showed that spatial separationof audio messages significantly improves the operator’s ability to recognize their content, regardlessof the type of interference. The maximum number of errors when recognizing a target messagecorresponds to its spatial position in the same direction as the noise of the interference. At thesame time, message recognition is significantly better if it is pronounced in a female voice. The fact ofspatial asymmetry of correct recognitions was also revealed: messages arriving from the right are recognized better than in cases of their arrival from the left. The practical significance of the researchconcerns the possibility of creating intercom with increased security against conflicts betweendifferent information flows, as well as against the impact of external acoustic noise. The prospect isseen in the use of three-dimensional audio interfaces not only as part of an intercom, but also fornavigation and aircraft control systems, as well as monitoring its state.

Psychophysical studies have shown that a sensation of depth can be elicited in the absence of both form and spatial disparity cues, if the input to the two eyes is separated in time. These data suggest that there is a “binocular delay” or “temporal disparity” system which can be used to localize objects in three-dimensional space.

At the end of a 300-year period of colonial expansion, Britain established four cities in the Southern Hemisphere; Sydney, Adelaide, Wellington and Auckland. This paper analyses the figure/ground condition of these cities in the early years of settlement by using maps and survey plans drawn between 1788 and 1848 sourced from archives in Australia and New Zealand. A close representational reading of the images reveals a progressive dissolving of the city as a legible object in three-dimensional space. These graphic shifts encapsulated a changeover in urban design sensibility from a city with a collective identity and physical presence, to one of individual association and aspiration occupying a dispersed horizontal terrain in the pre-suburban era.

In this paper, we propose a pose estimation method of an object in three-dimensional space without the pre-learning for AR application in the mobile device. One of the implementation methods of augmented reality is using a two dimensional marker. A two-dimensional marker is not robust in the case of change in complicated three-dimensional rotation. In our work, this problem is solved by a three-dimensional marker using a cube. In the study of a pose estimation of the three-dimensional object, a model-based method using evolutionary method has been proposed. This method cannot estimate all poses, because the rotation angle of the target object is limited. In this paper, we propose the pose estimation method of a cube using a property of cube with evolutionary method. This method is possible to estimate all pose by using property related to rotation of the cube. We evaluated the proposed method by experiments using the static image of object in real-world.