Refine
Year of publication
- 2006 (39) (remove)
Document Type
- Conference Proceeding (17)
- Contribution to a Periodical (14)
- Article (peer reviewed) (3)
- Book (3)
- Part of a Book (2)
Is part of the Bibliography
- no (39)
Keywords
- Trockenbau (6)
- FVK (4)
- Normierung (3)
- Holzbau (2)
- Innenausbau (2)
- Schallmesstechnik (2)
- Schallschutz (2)
- ARIS (1)
- Adhärenz (1)
- Augmented Reality (AR) (1)
The main focus of this work is the development of new methods for the self-calibration of a rigid stereo camera system. However, many of the algorithms introduced here have a wider impact, particularly in robot hand-eye calibration with all its different areas of application. Stereo self-calibration refers to the computation of the intrinsic and extrinsic parameters of a stereo rig using neither a priori knowledge on the movement of the rig nor on the geometry of the observed scene.
The stereo parameters obtained by self-calibration, namely rotation and translation from left to right camera, are used for computing depth maps for both images, which are applied for rendering correctly occluded virtual objects into a real scene (Augmented Reality).
The proposed methods were evaluated on real and synthetic data and compared to algorithms from the literature. In addition to a stereo rig, an optical tracking system with a camera mounted on an endoscope was calibrated without a calibration pattern using the proposed extended hand-eye calibration algorithm.
The self-calibration methods developed in this work have a number of features, which make them easily applicable in practice: They rely on temporal feature tracking only, as this monocular tracking in a continuous image sequence is much easier than left-to-right tracking when the camera parameters are still unknown.
Intrinsic and extrinsic camera parameters are computed during the self-calibration process, i.e., no calibration pattern is required. The proposed stereo self-calibration approach can also be used for extended hand-eye calibration, where the eye poses are obtained by structure-from-motion rather than from a calibration pattern.
An inherent problem to hand-eye calibration is that it requires at least two general movements of the cameras in order to compute the rigid transformation.
If the motion is not general enough, only a part of the parameters can be obtained, which would not be sufficient for computing depth maps. Therefore, a main part of this work discusses methods for data selection that increase the robustness of hand-eye calibration. Different new approaches are shown, the most successful ones being based on vector quantization.
The data selection algorithms developed in this work can not only be used for stereo self-calibration, but also for classic robot hand-eye calibration, and they are independent of the actually used hand-eye calibration algorithm.
We present a novel split and merge based method for dividing a given metric map into distinct regions, thus effectively creating a topological map on top of a metric one. The initial metric map is obtained from range data that are converted to a geometric map consisting of linear approximations of the indoor environment.
The splitting is done using an objective function that computes the quality of a region, based on criteria such as the average region width (to distinguish big rooms from corridors) and overall direction (which accounts for sharp bends).
A regularization term is used in order to avoid the formation of very small regions, which may originate from missing or unreliable sensor data. Experiments based on data acquired by a mobile robot equipped with sonar sensors are presented, which demonstrate the capabilities of the proposed method.
Hintergrund und Fragestellung: Bisphosphonate sind eine effektive Therapie der Osteoporose. Unverträglichkeiten, insbesondere gastrointestinale Nebenwirkungen, sind häufig Ursache von Therapieabbrüchen. Ziel der Untersuchung ist, Unterschiede der Adhärenz (Akzeptanz, Persistenz/Therapieabbruch, Compliance) zwischen täglicher (ALD-D) und wöchentlicher (ALD-W) Einnahmefrequenz bei dem Bisphosphonat Alendronat zu untersuchen.
Patienten und Methoden: Die Analyse beruht auf Verschreibungsdaten zweier Zufallsstichproben von jeweils 144 Patientinnen ab einem Alter von 45 Jahren mit täglicher bzw. wöchentlicher Einnahmefrequenz über einen Zeitraum von 12 Monaten ab Initiierung der Therapie. Ein Therapieabbruch war definiert als das Aufbrauchen der letzten Verschreibung. Akzeptanz wurde am Anteil der Patientinnen ohne Therapieabbruch nach der ersten Verschreibung gemessen. Compliance wurde am MPR (Medication possession ratio = prozentualer Anteil der Tage im Jahr, an denen Medikation vorliegt) gemessen. Therapeutisch relevante Compliance, die zur Reduktion von Frakturrisiken führte, war bei einem MPR >80 % gegeben.
Ergebnisse: 31,3 % (ALD-W) vs. 45,8 % (ALD-D) der Patienten brachen die Therapie nach der 1. Verschreibung, 53,5 % (ALD-W) vs. 72,2 % (ALD-D) brachen die Therapie im Verlauf eines Jahres ab. Die Abbrecherrate war unter täglicher Einnahme signifikant höher (p = 0,0035). Die durchschnittliche Dauer bis zum Therapieabbruch inklusive Therapieunterbrechungen betrug 220 Tage (ALD-W) vs. 169 Tage (ALD-D). Die durchschnittliche Compliance aller Patienten betrug 51,7 % (ALD-W) vs. 37,7 % (ALD-D). 30,6 % (ALD-W) vs. 19,2 % (ALD-D) (p = 0,0295) aller Patienten erreichten eine therapeutisch relevante Compliance.
Folgerungen: Eine große Zahl von Patienten brach die Therapie mit Bisphosphonaten ab, viele schon nach der ersten Verschreibung. Die Adhärenz wurde durch die Verringerung der Einnahmefrequenz verbessert, blieb aber suboptimal. Es besteht ein Bedarf für Therapien, die zu besserer Therapietreue führen können.
Alles dicht?
(2006)
Anschlussmodalitäten
(2006)
The tracheoesophageal (TE) substitute voice is currently state–of–the–art treatment to restore the ability to speak after laryngectomy. The intelligibility while talking over a telephone is an important clinical factor, as it is a crucial part of the patients’ social life. An objective way to rate the intelligibility of substitute voices when talking over a telephone is desirable to improve the post–laryngectomy speech therapy. An automatic speech recognition (ASR) system was applied to 41 high quality recordings of post–laryngectomy patients. The ASR system was trained with normal, non–pathologic speech. It yielded a word accuracy (WA) of 36.9%±18.0%; compared to the intelligibility rating of a group of human experts the ASR system had a correlation coefficient of -.88. After downsampling the 41 recordings to telephone quality, the ASR system reached a WA of 26.4%±13.9% leading to a correlation coefficient of -.80. These results confirm that an ASR system can be used for objective intelligibility rating over the telephone.
Bauen im Bestand: Dachausbau
(2006)
Diese Arbeit geht im Rahmen der qualitativen Forschung der Frage nach, was deutschsprachige Physiotherapeuten unter dem Begriff Clinical Reasoning verstehen. Clinical Reasoning und das angewandte Forschungsdesign werden erläutert. Die Ergebnisse zeigen ein uneinheitliches Verständnis von Clinical Reasoning und ein hohes Maß an Selbstreflexion als Ausdruck der Unsicherheit beim physiotherapeutischen Handeln. Es besteht Unzufriedenheit mit der Qualität der Grundausbildung, die nur unzureichende Kompetenz für die Berufsausübung vermittelt. Dafür notwendig und förderungsbedürftig sind bewusstes, strukturiertes und dokumentiertes Handeln. Clinical Reasoning muss ein wesentlicher Bestandteil der physiotherapeutischen Ausbildung werden.
This paper presents a novel algorithm for computing absolute space representations (ASRs) in Yeap, W.K. and Jefferies, M. (1988) for mobile robots equipped with sonar sensors and an odometer. The robot is allowed to wander freely (i.e. without following any fixed path) along the corridors in an office environment from a given start point to an end point. It then wanders from the end point back to the start point. The resulting ASRs computed in both directions are shown