Grey value thresholding is a segmentation technique commonly applied to tomographic image reconstructions. Many procedures have been proposed to optimally select the grey value thresholds based on the image histogram. In this paper, a new method is presented that uses the tomographic projection data to determine optimal thresholds. The experimental results for phantom images show that our metho...

The authors introduce a tool referred to as the Ultimate Intubation Head (UIH) to train medical practitioners’ hand-eye coordination in performing endotracheal intubation with the help of augmented reality methods. In this paper we describe the integration of a deployable UIH and present methods for augmented reality registration of real and virtual anatomical models. The assessment of the 52 d...

Objective: Computed tomography (CT)-based attenuation correction (CTAC) offers the clear benefit of reliable reconstruction of single-photon emission computed tomography (SPECT) images through its ability to achieve object-specific attenuation maps, but artifacts from dense materials often deteriorate CTAC performance. Therefore, we investigate the feasibility of CTAC in the presence of dense m...

The purpose of this study is to investigate multimodal visual-haptic texture perception for which we used virtual reality techniques. Participants judged a broad range of textures according to their roughness and their spatial density under visual, haptic and visual-haptic exploration conditions. Participants were well able to differentiate between the different textures both by using the rough...

We present an algorithm for estimating the blood flow in angiographic image data. In corresponding projective digital subtraction X-ray angiography (2D-DSA) data sets we analyze the correlation between Concentration Time Curves (CTC) of pixels along the vessel centerline. The appropriate spatial information is recovered by applying a 2D-3D registration re-projecting the centerline pixels to the...

The goal of dental education is to guide students’ development through different stages from novice to competent, eventually resulting in an expert clinician. Students traditionally devote several years to the acquisition of sufficiently fine manual skills to prepare them for entry-level dental practice. In the current simulation laboratory, training is restricted to non realistic procedures us...

Traditionally, tool tracking involves two subtasks: (i) detecting the tool in the initial image in which it appears, and (ii) predicting and refining the configuration of the detected tool in subsequent images. With retinal microsurgery in mind, we propose a unified tool detection and tracking framework, removing the need for two separate systems. The basis of our approach is to treat both dete...

Virtual Reality (VR) technology holds promise as a virtual prototyping tool for mechanical assembly; however, several developmental challenges still need to be addressed before virtual prototyping applications can successfully be integrated into the product realization process. This paper describes the development of SHARP (System for Haptic Assembly & Realistic Prototyping), a portable VR inte...