Assessment of Structure from Motion for Reconnaissance Augmentation and Bandwidth Usage Reduction

Modern militaries rely upon remote image sensors for real-time intelligence. A typical remote system consists of an unmanned aerial vehicle, or UAV, with an attached camera. A video stream is sent from the UAV, through a bandwidth-constrained satellite connection, to an intelligence processing unit. In this research, an upgrade to this method of collection is proposed. A set of synthetic images of a scene captured by a UAV in a virtual environment is sent to a pipeline of computer vision algorithms, collectively known as Structure from Motion. The output of Structure from Motion, a three-dimensional model, is then assessed in a 3D virtual world as a possible replacement for the images from which it was created. This study shows Structure from Motion results from a modifiable spiral flight path and compares the geoaccuracy of each result. A flattening of height is observed, and an automated compensation for this flattening is performed. Each reconstruction is also compressed, and the size of the compression is compared with the compressed size of the images from which it was created. A reduction of 49-60% of required space is shown

Forum Bildverarbeitung 2022

Bildverarbeitung verknüpft das Fachgebiet die Sensorik von Kameras – bildgebender Sensorik – mit der Verarbeitung der Sensordaten – den Bildern. Daraus resultiert der besondere Reiz dieser Disziplin. Der vorliegende Tagungsband des „Forums Bildverarbeitung“, das am 24. und 25.11.2022 in Karlsruhe als Veranstaltung des Karlsruher Instituts für Technologie und des Fraunhofer-Instituts für Optronik, Systemtechnik und Bildauswertung stattfand, enthält die Aufsätze der eingegangenen Beiträge

Accurate Simulation of Low-Intensity Transcranial Ultrasound Propagation for Neurostimulation

Neural stimulation with low-intensity ultrasound is a potentially transformative technology with applications in therapy and research. To develop, it will require ultrasound to be tightly focused on brain structures with accurate spatial targeting and fine control over the ultrasound amplitude at the target. However, the skull is an impediment to the effective focusing of ultrasound. Simulations of ultrasound propagation through acoustic property maps derived from medical images can be used to derive focusing drive signals for multi-element arrays. Focusing effectiveness is dependent on the fidelity of the numerical simulations. In combination with MRI based treatment verification, model based focusing has been used to focus high-intensity ultrasound onto the brain for ablation. This thesis presents a thorough and systematic study of the simulation parameters required to achieve effective transcranial focusing. The literature on ultrasonic neurostimulation, transcranial ultrasonic focusing, and the derivation of property maps from medical images is reviewed. The sampling criteria required to ensure numerical accuracy for the k-space pseudospectral time domain simulation scheme is established through testing of individual sources of numerical error, and convergence testing of a simulated time-reversal protocol. With numerical accuracy assured, the importance of acoustic property maps is examined through simulations to determine the sensitivity of intracranial fields to the properties of the skull layer. These results are corroborated by matching experimental measurements of ultrasound propagation through skull bone phantoms with spatially registered simulations. Finally, the impact of image related homogenisation and loss of internal bone structure is determined using simulations through co-registered clinical CT and micro-CT data of the skull

REAL-TIME ELASTOGRAPHY SYSTEMS

Ultrasound elastography is a technique that is often used to detect cancerous tumors and monitor ablation therapy by detecting changes in the stiffness of the underlying tissue. This technique is a computationally expensive due to the extensive searching between two raw ultrasound images, that are called radio frequency images. This thesis explores various methods to accelerate the computation required for the elastography technique to allow use during surgery. This thesis is divided into three parts. We begin by exploring acceleration techniques, including multithreading techniques, asynchronous computing, and acceleration of the graphics processing unit (GPU). Elastography algorithms are often affected by out-of-plane motion due to several external factors, such as hand tremors and incorrect palpation motion, amongst others. In this thesis, we implemented an end-to-end system that integrates an external tracker system to detect the in-plane motion of two radio frequency (RF) data slices. This in-plane detection helps to reduce de-correlated RF slices and produces a consistent elastography output. We also explore the integration of a da Vinci Surgical Robot to provide stable palpation motion during the surgery. The external tracker system suffers from interference due to ferromagnetic materials present in the operation theater in the case of an electromagnetic tracker, while optical and camera-based tracking systems are restricted due to human, object and patient interference in the path of sight and complete or partial occlusion of the tracking sensors. Additionally, these systems must be calibrated to give the position of the tracked objects with respect to the trackers. Although calibration and trackers are helpful for inter-modality registration, we focus on a tracker-less method to determine the in-plane motion of two RF slices. Our technique divides the two input RF images into regions of interest and performs elastography on RF lines that encapsulate those regions of interest. Finally, we implemented the world’s first known five-dimensional ultrasound system. We built the five-dimensional ultrasound system by combining a 3D B-mode volume and a 3D elastography volume visualized over time. A user controlled multi-dimensional transfer function is used to differentiate between the 3D B-mode and the 3D elastography volume

Proceedings of the International Workshop on Medical Ultrasound Tomography: 1.- 3. Nov. 2017, Speyer, Germany

Ultrasound Tomography is an emerging technology for medical imaging that is quickly approaching its clinical utility. Research groups around the globe are engaged in research spanning from theory to practical applications. The International Workshop on Medical Ultrasound Tomography (1.-3. November 2017, Speyer, Germany) brought together scientists to exchange their knowledge and discuss new ideas and results in order to boost the research in Ultrasound Tomography

Forum Bildverarbeitung 2022

Image processing combines the disciplines of cameras – image-based sensors – with the processing of the sensor data – the images. From this follows the particular attraction of this field. The conference proceedings at hand of the “Image Processing Forum”, which took place on 24.-25.11.2022 in Karlsruhe as a common event of the Karlsruhe Institute of Technology and the Fraunhofer Institute of Optronics, System Technologies and Image Exploitation, contain the articles of the contributions