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Currently, the price of digital camera is decreasing and many users afford to purchase it. The digital camera can be used for many applications. The digital camera can also be used for accurate measurement such as determination of three dimensional (3D) coordinates, production of accurate measurement and generation of 3D model of objects. However, the digital camera need to be calibrated to obtain...
In this paper, we report on an experiment conducted to test the effects of different hand representations on near space pointing performance and user preference. Subjects were presented with varying levels of hand realism, including real hand video, a high and a low level 3D hand model and an ordinary 3D pointer arrow. Behavioural data revealed that an abstract hand substitute like a 3D pointer arrow...
In this paper, we present the results of a user study with a bimanual haptic setup. The goal of the experiment was to evaluate if Guiard's theory of the bimanual frame of reference can be applied to interaction tasks in virtual environments (VE) with haptic rendering. This theory proposes an influence of the non-dominant hand (NDH) on the dominant hand (DH). The experiment was conducted with multiple...
Issues such as hand and tracker jitter negatively affect user performance with the ray-casting selection technique in 3D environments. This makes it difficult for users to perform tasks that require them to select objects that have a small visible area, since small targets require high levels of precision. We introduce an approach to address this issue that uses progressive refinement of the set of...
This paper considers the problem of recognizing the visual and sound information by constructing a virtual environment, which allows to qualitatively simplify the system and to carry out of experiments, and to create an algorithmic model of pattern recognition comparable to human capabilities. Our research is aimed at obtaining an algorithmic model that can extract from the surrounding world “meaningful”...
Co-located collaborative tasks allow teams to leverage the skills of each individual member. While numerous guidelines exist to develop visualizations for individuals working on desktops, very little is known about how groups of individuals interpret and comprehend diverse types of visual constructs on larger displays. To study whether group size impacts the collective understanding of relationships...
This paper presents how using a correspondence-based interpolation scheme for 3D image registration improves the registration accuracy. The interpolator takes into account correspondences across slices, which is an advantage, particularly when the volume has thick slices, and where anatomies lie non-parallel to the slice direction. We use our previously presented approach for correspondence-based...
The estimation of the mid-sagittal plane (MSP) is a known problem with several applications in neuroimage analysis. As advance to the state-of-the-art, we present a considerably better approach for MSP extraction based on bilateral symmetry maximization and a more suitable error metric to compare MSP estimation methods. The proposed method was quantitatively evaluated using three other state-of-the-art...
In this paper, we present a novel methodology for computing statistical shape models (SSM's) by leveraging the medial axis model to determine shape variations between objects. Landmark based SSM's (LSSM's) are a popular approach to describing valid shape variation in an object of interest by applying principal component analysis to a set of landmarks on the surface of the object. However, defining...
Plaque composition analysis is a critical tool in identifying vulnerable atherosclerotic plaques. Intravascular ultrasound with spectral analysis of the backscattered radio frequency (RF) signals (IVUS-VH) is currently considered as the gold standard for the evaluation of coronary plaque composition, while CT coronary angiography (CTA) has been proposed as a potential non-invasive counterpart. In...
Image-guided neurosurgery requires navigation in 3D using a computer-assisted surgery system that tracks surgical tools in realtime and displays their positions with respect to the preoperatively acquired images (e.g. CT, MRI, fMRI etc.) A key problem in image guided procedures is the need to navigate to specific locations highlighted in the images, such as image-derived functional areas, that have...
We present a new method for reconstructing a 3D flow field from multiple 3D Pulsed Wave Doppler echo images. A weakness of Doppler imaging is that only a 1D projection of the true 3D velocity (parallel to the echo beam direction) is measured. We propose a method which uses registered multiple Doppler views to calculate 3D flow vectors using a Least Mean Squares (LMS) minimisation process. Flow is...
In this work, we present a novel content-based 3D shape retrieval system for Abdominal Aortic Aneurysm (AAA) rupture risk prediction. The algorithms incorporate shape context, RANdom SAmple Consensus (RANSAC) and thin plate spline (TPS) to achieve a reliable AAA rupture risk assessment system. Pre-labeled unruptured and ruptured cases (`-1' for unruptured and `1' for ruptured cases) are built and...
The registration of temporal 2D X-ray mammograms is a challenging task which is difficult in part due to the superimposition of structures found in the breast together with the complex 3D deformation that the breast undergoes during compression. This paper presents an investigation into a method for registration of 2D mammographic images which accounts for varying displacements through the breast...
Image transformation is one of the important digital image processing techniques widely used in medical science. Typical applications of image transformation include creation of three dimensional volumetric models from two dimensional images. The two dimension images may be obtained energy source used for hard tissue imaging are x-rays. The three dimension models of hard tissue are created by traditional...
A new calibration algorithm for multi-camera systems using a small 3D reference rig is proposed. Extrinsic and intrinsic parameters of the cameras are recovered only by capturing the reference rig placed at different locations. Thus the proposed method yields a simple calibration means for multi-camera systems while not using large reference rig, which should occupy the image capture volume as full...
In this paper, the authors describe on a method of object identification by verification of Hough data. In this study, for corresponding to three-dimensional change of camera, we pay attention to the distribution pattern of Hough data. A positional relationship of the peaks as Hough data shows tendency to be kept, in case of camera shooting condition change. Using a characteristic of Hough data, it...
In order to create valid CAD (computer-aided design) model for planning orthopedic operations, rapid prototyping, designing of implants, etc., the accurate definition of geometry and topology of all regions of human tibia is essential. Therefore it is logical to base process of geometrical modeling of human tibia on its anatomical and morphological properties. This paper presents and compares the...
A series of oscillatory radial basis functions (RBFs) with Bessel functions of different orders are compared at different cube lengths. An adaptive choice of the interpolation functions with the best orders is then adopted to enhance the interpolation accuracy when implementing the multilevel Green's function interpolation method (MLGFIM). In order to further improve the interpolation accuracy, a...
Wireless Sensor Network for their rapid deployment can be used in habitat monitoring for detecting fire and in disaster for helping rescue teams. Node localization is key factor for some applications. We propose the Triangular Centroid Localization algorithm (TCL). It is based in simple trigonometric figures and it does not require special hardware or synchronization time. In our simulations using...
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