Color Layer Scissioning in See-Through Augmented Reality

Color appearance of transparent objects is not adequately described by colorimetry or color appearance models. Despite the fact that the retinal projection of a transparent object is a combination of its color and the background, measurements of this physical combination fail to predict the saliency with which we perceive the object’s color. When the perceive color forms in the mind, awareness of their physical relationship separates the physical combination into two unique perceptions. This is known as color scissioning. In this paper a psychophysical experiment utilizing a seethrough augmented reality display to compare virtual transparent color samples to real color samples is described and confirms the scissioning effect for lightness and chroma attributes. A previous model of color scissioning for AR viewing conditions is tested against this new data and does not satisfactorily predict the observers’ perceptions. However, the model is still found to be a useful tool for analyzing the color scissioning and provides valuable insight on future research directions

Towards Assembly Information Modeling (AIM)

Nowadays digital tools support architects, engineers and constructors in many specific tasks in the construction industry. While these tools are covering almost all aspects of design and manufacturing, the planning and design for the assembly of buildings remain an unexplored area. This research aims to lay the foundations of a new framework for the design for assembly in architectural applications entitled Assembly Information Modeling. In practice, it is a central digital model containing the structure architectural design, construction details, three dimensional representations, assembly sequences, issue management and others. This framework forms the base for a multitude of novel applications for assembly design, planning and execution, such as assembly simulation and strategies communication, problem detections in the early design phases and interdisciplinary coordination. This paper describes the specifications of the digital assembly model and illustrate two use cases: collaborative assembly design using AEC cloud-based platforms and Augmented Assembly using Augmented reality devices

Image-guided port placement for minimally invasive cardiac surgery

Minimally invasive surgery is becoming popular for a number of interventions. Use of robotic surgical systems in coronary artery bypass intervention offers many benefits to patients, but is however limited by remaining challenges in port placement. Choosing the entry ports for the robotic tools has a large impact on the outcome of the surgery, and can be assisted by pre-operative planning and intra-operative guidance techniques. In this thesis, pre-operative 3D computed tomography (CT) imaging is used to plan minimally invasive robotic coronary artery bypass (MIRCAB) surgery. From a patient database, port placement optimization routines are implemented and validated. Computed port placement configurations approximated past expert chosen configurations with an error of 13.7 ±5.1 mm. Following optimization, statistical classification was used to assess patient candidacy for MIRCAB. Various pattern recognition techniques were used to predict MIRCAB success, and could be used in the future to reduce conversion rates to conventional open-chest surgery. Gaussian, Parzen window, and nearest neighbour classifiers all proved able to detect ‘candidate’ and ‘non-candidate’ MIRCAB patients. Intra-operative registration and laser projection of port placements was validated on a phantom and then evaluated in four patient cases. An image-guided laser projection system was developed to map port placement plans from pre-operative 3D images. Port placement mappings on the phantom setup were accurate with an error of 2.4 ± 0.4 mm. In the patient cases, projections remained within 1 cm of computed port positions. Misregistered port placement mappings in human trials were due mainly to the rigid-body registration assumption and can be improved by non-rigid techniques. Overall, this work presents an integrated approach for: 1) pre-operative port placement planning and classification of incoming MIRCAB patients; and 2) intra-operative guidance of port placement. Effective translation of these techniques to the clinic will enable MIRCAB as a more efficacious and accessible procedure

Intraoperative Planning and Execution of Arbitrary Orthopedic Interventions Using Handheld Robotics and Augmented Reality

The focus of this work is a generic, intraoperative and image-free planning and execution application for arbitrary orthopedic interventions using a novel handheld robotic device and optical see-through glasses (AR). This medical CAD application enables the surgeon to intraoperatively plan the intervention directly on the patient’s bone. The glasses and all the other instruments are accurately calibrated using new techniques. Several interventions show the effectiveness of this approach

Augmented Reality and Its Application

Augmented Reality (AR) is a discipline that includes the interactive experience of a real-world environment, in which real-world objects and elements are enhanced using computer perceptual information. It has many potential applications in education, medicine, and engineering, among other fields. This book explores these potential uses, presenting case studies and investigations of AR for vocational training, emergency response, interior design, architecture, and much more

Geometry vs Realism: an exploration of visual immersion in a synthetic reality space

With the broader aim of using a synthetic reality environment to improve and develop packaging designs for Welsh food Small-Medium Enterprises (SME), two studies were undertaken in a simulated environment to explore the geometry and realism of visual content of supermarket shelves, in relation to psychological variables that correlate with sense of presence. The first experiment compared two types of visual geometry: Linear perspective and ‘Natural’ perspective (using non-linear projection techniques) as well as the realism of the depicted supermarket scene (by comparing a Computer Aided Design (CAD) image versus a photograph). Results from the first experiment showed that the type of image geometry had more of an impact on the sense of presence than the realism of the depicted supermarket scene. A second study was then conducted to test whether a hybrid image of CAD components and a photograph could create a similar sense of presence compared with a photograph alone (because the use of a hybrid image can reduce costs). The results showed that there were no significant differences between the hybrid image and the photograph in terms of creating a sense of presence