In this work we present how Augmented Reality (AR) can be used to create an intimate integration of process data with
the workspace of an industrial CNC (computer numerical control) machine. AR allows us to combine interactive
computer graphics with real objects in a physical environment - in this case, the workspace of an industrial lathe.
ASTOR is an autostereoscopic optical see-through spatial AR system, which provides real-time 3D visual feedback
without the need for user-worn equipment, such as head-mounted displays or sensors for tracking. The use of a
transparent holographic optical element, overlaid onto the safety glass, allows the system to simultaneously provide
bright imagery and clear visibility of the tool and workpiece. The system makes it possible to enhance visibility of
occluded tools as well as to visualize real-time data from the process in the 3D space. The graphics are geometrically
registered with the workspace and provide an intuitive representation of the process, amplifying the user's understanding
and simplifying machine operation.
The first prototype of the Interaction Table was presented at the Electronic Imaging conference in 2004. In this paper we describe the progress made with the second prototype.
The Interaction Table uses a autostereoscopic display, in reflection mode, to show a computer-generated three-dimensional image to a small number of people. The display is mounted as a table top so that the users can discuss freely while interacting with the image. Target applications include, e.g., product development, planning, surveying, military command, education, and medicine.
Recently we work to increase the size four times to 60 x 80 cm. Furthermore, the field of view for each viewing position has been extended up to 120 degrees by the use of a specially made holographic optical element.
The second prototype can be driven by a number of PC:s connected by a Ethernet network and/or by a single SGI Onyx computer with a number of separate graphics channels.
For both the PC setup and the SGI system specially designed software written in Java or commercially available CAD visualization software can be used.
We have identified the need for, and started development of, a new tool we call an interaction table. In this paper the experiences with the first prototype are described. The interaction table presents a computer-generated, autostereoscopic, three-dimensional image that can be viewed and interacted with.
KEYWORDS: Holography, 3D acquisition, Holograms, Digital holography, 3D modeling, Visualization, 3D image processing, Charge-coupled devices, Holographic interferometry, Finite element methods
Looking back on the earlier reports on Holography in Sweden, it is striking that not much has changed during the last decade. It is more or less the same people that have been active throughout this period. It is difficult to say if holography is loosing or winning ground in Sweden. In spite of this a lot of new and interesting work has been done.
A short popular overview is given of the possibilities of finding new pulsed laser sources for making holograms. Special emphasis is made on wavelengths suitable for color holography.
A system for transmission and previsualization of digital data for production of holographic stereograms has been developed. The aim of this system is to help the communication between producers of holographic stereograms and their clients. The client accesses the system through a Java applet, a small program, which is automatically downloaded and run on the clients local computer. The client loads a file in VRML format into the applet and the 3D model is displayed using the VRML browser plug-in usually delivered with WWW browsers. The Java applet overrides the controls of the VRML browser and provides only the manipulations possible and necessary for preparing the hologram production and visualizing the result. The applet permits the client to somewhat modify the scene e.g. by adding lights and manipulating them. After finishing the settings and visualizations of the hologram, the client may save the file with the new settings on her own computer in order to resume work later on. When satisfied she may upload the file with all settings to the hologram producer. The computer of the hologram producer is running a small, specially designed http server which will receive the file from the client for further handling.
KEYWORDS: Holography, 3D modeling, Digital holography, Visualization, 3D image processing, 3D metrology, Stereoscopic cameras, Finite element methods, Computer aided design, Image resolution
In the development of new products there are two parallel lines for the development process to follow; the traditional or 'real,' and the new computer aided or 'virtual.' The traditional line is to develop prototypes that can be used for testing strength, functionality, and visual appearance of the product. In the virtual line digital (CAD) models are developed which can be tested entirely in a computer by simulations e.g., using Finite Element Analysis (FEA) and other tools. For transformation from the real to the virtual world some kind of 3D camera is needed. The shape of the model should be measured together with further data concerning the visual appearance, material properties, etc. We have developed electronic recording techniques for doing this based on the Light-in-Flight technique. This technology has all advantages of holography, i.e., apart from the shape it is also possible to measure how much light is reflected from different parts of the object along with interferometric information, which can give mechanical data for the object. This can be used for example for visualization and to give tactile and haptic information to a virtual reality system about how the object would be perceived by a person touching it.
Holographic hard-copy techniques suffers from a lack of availability for ordinary users of computer graphics. The production of holograms usually requires special skills as well as expensive equipment which means that the direct production cost will be high for an ordinary user with little or no knowledge in holography. Here it is shown how a system may be created in which the users of computer graphics can do all communication with a holography studio through a Java-based web browser. This system will facilitate for the user to understand the technique of holographic stereograms, make decisions about angles, views, lighting etc., previsualizing the end result, as well as automatically submit the 3D-data to the producer of the hologram. A prototype system has been built which uses internal scripting in VRML.
As a part of a project for using short laser pulses and holographic techniques to measure three-dimensional shapes, measurements have been carried out of the pulse shapes of laser pulses from a mode-locked argon-ion pumped dye laser with autocorrelator, light-in-flight recording by holography and nonscanning white-light interferometer. The aim of the study is to find a reliable, inexpensive and fast method for measuring the pulse length of laser pulses in the picosecond region, when exposing and reconstructing the light-in-flight hologram, in respect to pulse width, symmetry and signal-to- noise ratio. Experimental results, along with the theoretical background, from these tests are accounted for in this presentation.
An easily implemented and easily manageable system for timeresolved holographic interferometry is presented. The system consists of a multiple-pulsed Q-switched ruby laser and a rotating disk having radial slits with a constant angular separation. The disk is used to scan the reference beam along a holographic plate, thereby achieving spatial multiplexing. Since the influence on the beam is negligible and a single slit is illuminated by every laser pulse, there is no need for synchronization. The interferometric pattern is achieved by removing the disk and exposing a reference image on the holographic plate. The system may serve as an excellent tool for full-field dynamic measurements. A simple experiment has been performed showing a sequence of momentary interference patterns on a vibrating plate.
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