KEYWORDS: 3D modeling, Acoustics, Data modeling, Latex, Process modeling, Laser therapeutics, 3D metrology, Tissues, Magnetic resonance imaging, Silicon
Human communication is to a large extend based on the use and variation of the voice. The correct use of the vocal system is learned from childhood on by auditory feedback. Hearing-impaired people do not receive this acoustic feedback and alternative methods are used if language is to be learned in addition to other forms of communication. Resonance frequencies play a decisive role in the formation of vowels. Hearing-impaired people may not be able to hear the vowel dependent resonances; however, they might be able to feel the corresponding vibrational structure within their vocal tract. In order to elucidate this process further, we performed vibrometric measurements of 3D printed model with uniform wall thickness which was acoustically excited with via a broadband loudspeaker. The resonance frequencies in the range of 100 - 5000Hz were clearly visible and the locations of the strongest vibrations could be determined. Furthermore, vibrometric data showed specific regions, were hearing-impaired people may feel some vibrations if the vowels are supported by the vocal tract structure. Vibrometric data, such as velocity amplitudes at selected regions and frequencies could be measured.
In Germany there are millions of people in retirement age which are living alone. Approx. 30% of them come into emergency situation because of a fall once a year. If the fall leads to bone fracture, the person isn’t able to stand off by itself and if there is nobody recognizing the situation, the fall can lead to death. Therefore a detector is developed, which can detect a person lying on the ground and send a signal to a family member in case of emergency. The system is built optically, which makes it insensitive to outer factors like humidity or thermal drifts. Vice versa it won’t apply any electromagnetic radiation onto medical devices situated in the room. The whole system consists of a laser, a material which shows birefringence, two polarizers and a detector. The material covers a big area in the apartment, which needs to be watched by a senor. If the senor is under strain, the polarization of the light will change its direction while passing the material and the system will measure an increase of light intensity after the 2nd polarizer. To discriminate an emergency from normal everyday situation, an algorithm is implemented, which asks for three steps to be positive ere the system triggers a signal. If the system has access to an already existing smart home-system, a signal can be activated to inform the person’s next relatives or even an emergency service. The systems works best, if the apartment is built newly
Online process control systems often only detecting temperatures at a local area of the machining point and determining an integrated value. In order to determine the proper welding quality and the absence of defects, such as temperature induced stress cracks, it is necessary to do time and space resolved measurements before, during and after the production process. The system under development consists of a beam splitting unit which divides the electromagnetic radiation of the heated component on two different sensor types. For high temperatures, a sensor is used which is sensitive in the visible spectrum and has a dynamic range of 120dB.1 Thus, very high intensity differences can be displayed and a direct analysis of the temperature profile of the weld spots is possible.2 A second sensor is operating in the wavelength range from 1 micron to 5 microns and allows the determination of temperatures from approximately 200°C.3
At the beginning of a welding process, the heat-up phase of the metal is critical to the resultant weld quality. If a defined temperature range exceeded too fast, the risk of cracking is significantly increased.4 During the welding process the thermal supervision of the central processing location is decisive for a high secure weld. In the border areas as well as in connection of the welding process especially cooling processes are crucial for the homogeneity of the results. In order to obtain sufficiently accurate resolution of the dynamic heating- and cooling-processes, the system can carry out up to 500 frames per second.
With 332,000 operations carried out every year, the implantation of an artificial hip joint is one of the most common
surgical operations performed in the US. According to prognosis which takes the demographical change into account, the
number of these operations will increase in the coming years.
One of the essential requirements is the perfect reconstruction of the biomechanical functions, especially the knowledge
about the center of the hip rotation and the length of the leg. Based on this information it is possible to ensure the right
position of the newly set leg during surgery.
The aim of this work is to present and evaluate an optical measurement method in order to gather information about the
center of the hip joint and the leg length. An appropriate laboratory setup has been designed and implemented in order to
evaluate two different approaches: a structured light-method consisting of a DLP-Beamer or a laser source which
projects defined patterns onto the patient and a marker-based system. Together with this both methods are combined
with custom software to determine the hip joint center and the leg length with an accuracy of around +/- 0.2 inches. The
clinical use of the tested approaches would give the surgeon the opportunity to reset the implant-parameters in the course
of the surgery. In this way subsequent illnesses such as scoliotic pelvis can be prevented.
The production of complex titanium components for various industries using laser welding processes has received growing attention in recent years. It is important to know whether the result of the cohesive joint meets the quality requirements of standardization and ultimately the customer requirements. Erroneous weld seams can have fatal consequences especially in the field of car manufacturing and medicine technology. To meet these requirements, a real-time process control system has been developed which determines the welding quality through a locally resolved temperature profile. By analyzing the resulting weld plasma received data is used to verify the stability of the laser welding process. The determination of the temperature profile is done by the detection of the emitted electromagnetic radiation from the material in a range of 500 nm to 1100 nm. As detectors, special high dynamic range CMOS cameras are used. As the emissivity of titanium depends on the wavelength, the surface and the angle of radiation, measuring the temperature is a problem. To solve these a special pyrometer setting with two cameras is used. That enables the compensation of these effects by calculating the difference between the respective pixels on simultaneously recorded images. Two spectral regions with the same emissivity are detected. Therefore the degree of emission and surface effects are compensated and canceled out of the calculation. Using the spatially resolved temperature distribution the weld geometry can be determined and the laser process can be controlled. The active readjustment of parameters such as laser power, feed rate and inert gas injection increases the quality of the welding process and decreases the number of defective goods.
Minimal invasive surgery methods have received growing attention in recent years. In vital important areas, it is crucial for the surgeon to have a precise knowledge of the tissue structure. Especially the visualization of arteries is desirable, as the destruction of the same can be lethal to the patient. In order to meet this requirement, the study presents a novel assistance system for endoscopic surgery. While state-of-the art systems rely on pre-operational data like computer-tomographic maps and require the use of radiation, the goal of the presented approach is to provide the clarification of subjacent blood vessels on live images of the endoscope camera system. Based on the transmission and reflection spectra of various human tissues, a prototype system with a NIR illumination unit working at 808 nm was established. Several image filtering, processing and enhancement techniques have been investigated and evaluated on the raw pictures in order to obtain high quality results. The most important were increasing contrast and thresholding by difference of Gaussian method. Based on that, it is possible to rectify a fragmented artery pattern and extract geometrical information about the structure in terms of position and orientation. By superposing the original image and the extracted segment, the surgeon is assisted with valuable live pictures of the region of interest. The whole system has been tested on a laboratory scale. An outlook on the integration of such a system in a clinical environment and obvious benefits are discussed.
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