Computing visibility functions using polygon intersection algorithms

Creating photorealistic images is one of the ultimate goals of computer graphics. Previous work has shown that a material's microstructure plays a crucial role when trying to achieve photorealism. This is because a material's appearance depends on the roughness of its microstructure. Due to this dependence, effects such as masking and shadowing...

Shining a light on material appearance: Mapping NDFs to heightfields

This research proposes a new algorithm for mapping Normal Distribution Functions to Heightfields in order to answer its research question: ”Given an NDF, how can we generate a corresponding Heightfield using simple optimization algorithms?”. This research is important, as it helps us to gain a better understanding of how limited statistics-based...

Approximating a full Bidirectional Reflectance Distribution Function from a slice: Creating a BRDF trough solids of revolution

Bidirectional Reflectance Distribution Functions, BRDFs, describe the reflectance of light on a ma-terial, and are widely used in computer graphics to render materials. Acquiring a full measured BRDF can be costly and time consuming, so this research aims to answer the question ”How can we approx-imate a full BRDF from a single slice (in-plane...

Soft Peaks: The effects of smoothing on ray reflections

The micro detail on surfaces can have a profound effect on how rays bounce of it. In ray tracing, this micro-surface is normally approximated with statistical models. We wish to figure out what the effect of normal interpolation and Phong tessellation is on how rays reflect on the surface. This has been Done by creating a ray tracers from...

A New Baseline for Feature Description on Multimodal Scans of Paintings

Multimodal imaging is used by conservators and scientists to study the composition of paintings. To aid the combined analysis of these scans, such images must first be aligned. Rather than proposing a new domain-specific descriptor, we explore and evaluate how existing feature descriptors from related fields can improve the performance of...

Scale invariant image registration in the domain of art conservation

Image registration is the process that overlays two or more images from different sources taken at different times and angles. Art conservators take various scans of paintings and then register them against the original in order to learn more about the working style of the artist, materials used and physical changes throughout time. This paper...

Aligning non-exact copies of artworks with their original

This research investigates the efficacy and reliability of geometric matching for the specific case of aligning non-exact copies of artistic works with the original from which they were derived. The purpose of which is to provide a foundation for comparison in any further analysis conducted by conservators and art historians. An overview of the...

Improving Image Registration Accuracy through User Interaction

The current state-of-the-art image alignment techniques and their input parameters are often unintuitive to those without the required background knowledge.<br/>This work aims to provide users with a graphical user interface through which they can intuitively influence the parameters and results of the algorithm by excluding certain areas from...

The contribution of grayscale cameras to the accuracy of surgical augmented reality goggles

The way that surgeons currently use surgical navigation technology impacts their hand-eye coordination and their ability to view images and data critically. To tackle this issue Augmented Reality goggles, built from the HoloLens 2, have been developed specifically for the purpose of aiding surgeons during surgery and it is called: The HoloNav....

HoloNav: HoloLens as a Surgical Navigation System: Detecting optical reflective spheres using YOLOv5 and the Hololens' grayscale cameras

Surgical navigation is a tool that surgeons rely on everyday to perform accurate surgeries all over the world. However, this technology requires good hand-eye coordination and a high level of concentration. HoloNav is a project that inquires to see if using the HoloLens and augmented reality can replace the current surgical navigation methods....

Utilising Deep Learning Models for the Surface Registration Problem in HoloNav

Surface Registration is a registration problem that handles the registration of two similar surfaces. In most research that utilises Deep Learning (DL) models to handle surface registration two theories are investigated; the first being whether surfaces sampled from the same origin can be registered together, and the second theory being whether...

Accuracy of the Hololens 2’s infrared cameras in the context of surgical navigation

Patient and instrument tracking are fundamental parts of surgical navigation systems. Traditional surgical navigation systems rely on stationary cameras for tracking and stationary screens for presenting information. An increased mental load is exerted by surgeons as they switch focus between the surgical site and the presented data. By...

Performing patient alignment utilizing point-cloud surface registration techniques in HoloNav

In order to be able to use the Microsoft HoloLens for surgical navigation purposes, performing good patient alignment is of utmost importance. This paper will discuss how this patient alignment can be done using different point cloud registration algorithms.<br/>A lot of research is being conducted on point cloud registration algorithms. However...

Physics-based sail reconstruction from 3D-markers

To design more efficient sailing boat sails and to analyze the efficiency of a sail trim on the water, it is very helpful to have the ability to obtain a digital copy of real-life sail configurations. As a step towards obtaining such digital copies, the Sailing Innovation Centre in collaboration with GeoDelta has created point cloud measurements...

Real-Time Relighting of Human Faces with a Low-Cost Setup

Video-streaming services usually feature post-processing effects to replace the background. However, these often yield inconsistent lighting. Machine-learning-based relighting methods can address this problem, but, at real-time rates, are restricted to a low resolution and can result in an unrealistic skin appearance. Physically-based rendering...

Fast approximation of the inverse reflector problem

Suppose we have a target radiance distribution, a light source, and a plane for receiving light. How do we design a reflector that can give a similar result as the target radiance distribution? The inverse reflector problem is of high interest for light designers and related industries, such as lamp manufacture, headlight and street light design...

Mice Tracking Using Infrared Subcutaneous Implants for Error Detection

The objective of this thesis was to develop a rodent tracker using the FlashTrack implants, and allow for tracking data to be used for behavioural research. The task was split into three main problems: detection, tracking and error detection. The detection was solved with basic image processing. The first step was background removal, using...

AR-assisted craniotomy planning for tumor resection

A craniotomy is a procedure were a neurosurgeon has to open the skull to gain direct access to the brain. When a brain tumor has to be removed from a patient, the craniotomy position is of great importance. This mostly defines the access path from the skull surface to the tumor and thus also what healthy brain tissue will be removed to access to...