Creating Simplified 3D Models with High Quality Textures

This paper presents an extension to the KinectFusion algorithm which allows creating simplified 3D models with high quality RGB textures. This is achieved through (i) creating model textures using images from an HD RGB camera that is calibrated with Kinect depth camera, (ii) using a modified scheme to update model textures in an asymmetrical colour volume that contains a higher number of voxels than that of the geometry volume, (iii) simplifying dense polygon mesh model using quadric-based mesh decimation algorithm, and (iv) creating and mapping 2D textures to every polygon in the output 3D model. The proposed method is implemented in real-time by means of GPU parallel processing. Visualization via ray casting of both geometry and colour volumes provides users with a real-time feedback of the currently scanned 3D model. Experimental results show that the proposed method is capable of keeping the model texture quality even for a heavily decimated model and that, when reconstructing small objects, photorealistic RGB textures can still be reconstructed.Comment: 2015 International Conference on Digital Image Computing: Techniques and Applications (DICTA), Page 1 -

Large object segmentation with region priority rendering

The Address Recalculation Pipeline is a hardware architecture designed to reduce the end-to-end latency suffered by immersive Head Mounted Display virtual reality systems. A demand driven rendering technique known as priority rendering was devised for use in conjunction with the address recalculation pipeline. Using this technique, different sections of a scene can be updated at different rates, resulting in reductions to the rendering load.Further reductions can potentially be achieved by allowing for the segmenting of large objects. However in doing so a tearing problem surfaces, which has to be overcome before large object segmentation can be used effectively in priority rendering. This paper demonstrates a way of organizing virtual world objects for priority rendering, as well as a method to hide scene tearing artefacts due to object segmentation

On the security of text-based 3D CAPTCHAs

CAPTCHAs have become a standard security mechanism that are used to deter automated abuse of online services intended for humans. However, many existing CAPTCHA schemes to date have been successfully broken. As such, a number of CAPTCHA developers have explored alternative methods of designing CAPTCHAs. 3D CAPTCHAs is a design alternative that has been proposed to overcome the limitations of traditional CAPTCHAs. These CAPTCHAs are designed to capitalize on the human visual system\u27s natural ability to perceive 3D objects from an image. The underlying security assumption is that it is difficult for a computer program to identify the 3D content. This paper investigates the robustness of text-based 3D CAPTCHAs. In particular, we examine three existing text-based 3D CAPTCHA schemes that are currently deployed on a number of websites. While the direct use of Optical Character Recognition (OCR) software is unable to correctly solve these textbased 3D CAPTCHA challenges, we highlight certain patterns in the 3D CAPTCHAs can be exploited to identify important information within the CAPTCHA. By extracting this information, this paper demonstrates that automated attacks can be used to solve these 3D CAPTCHAs with a high degree of success

Covert QR codes: How to hide in the crowd

This paper investigates a novel approach of distributing a hidden message via public channels. The proposed approach employs visual subterfuge to conceal secret information within a QR code. Using a QR code reader, any individual can decode the public information contained in the QR code. However, only authorized users who have the necessary credentials will be able to obtain the secret message, which is encoded in the form of a secret QR code. We call this a Covert QR (CQR) code scheme. To embed the secret information, this approach exploits the error correction mechanism inherent in the QR code structure. By using QR codes to conceal information, the proposed scheme has the advantage of reducing the likelihood of attracting the attention of potential adversaries. In addition, the information in QR codes can be scanned and decoded through the visual channel. As such, the secret information can be distributed on printed media and is not restricted to an electronic form

Metamorphic Testing of Navigation Software: A Pilot Study with Google Maps

Millions of people use navigation software every day to commute and travel. In addition, many systems rely upon the correctness of navigation software to function, ranging from directions applications to self-driving machinery. Navigation software is difficult to test because it is hard or very expensive to evaluate its output. This difficulty is generally known as the oracle problem, a fundamental challenge in software testing. In this study, we propose a metamorphic testing strategy to alleviate the oracle problem in testing navigation software, and conduct a case study by testing the Google Maps mobile app, its web service API, and its graphical user interface. The results show that our strategy is effective with the detection of several real-life bugs in Google Maps. This study is the first work on automated testing of navigation software with the detection of real-life bugs

Authentication and transaction verification using QR codes with a mobile device

User authentication and the verification of online transactions that are performed on an untrusted computer or device is an important and challenging problem. This paper presents an approach to authentication and transaction verification using a trusted mobile device, equipped with a camera, in conjunction with QR codes. The mobile device does not require an active connection (e.g., Internet or cellular network), as the required information is obtained by the mobile device through its camera, i.e. solely via the visual channel. The proposed approach consists of an initial user authentication phase, which is followed by a transaction verification phase. The transaction verification phase provides a mechanism whereby important transactions have to be verified by both the user and the server. We describe the adversarial model to capture the possible attacks to the system. In addition, this paper analyzes the security of the propose scheme, and discusses the practical issues and mechanisms by which the scheme is able to circumvent a variety of security threats including password stealing, man-in-the-middle and man-in-the-browser attacks. We note that our technique is applicable to many practical applications ranging from standard user authentication implementations to protecting online banking transactions

The ARP Virtual Reality System in Addressing Security Threats and Disaster Scenarios

Nations, corporations and political organizations around the world today are forced to deal with an increasing number of security threats. As a result, various organizations must find ways to adequately equip and prepare themselves to handle numerous dangerous and life threatening circumstances. Virtual reality is an extremely important technology that can be used across a variety of different fields and for a number of diverse applications, ranging from simulation training to visualization tools, in order to prepare for and manage disaster situations. Head mounted display (HMD) virtual reality systems attempt visually to immerse the user in a virtual environment. However, it is well recognized that latency, the delay in responding to a user\u27s head movement, is a major shortcoming that plagues immersive HMD virtual reality systems. Excessive latency destroys the illusion of reality that such systems attempt to present to the user. A hardware architecture known as the address recalculation pipeline (ARP) and a computer graphics rendering technique called priority rendering, were designed to reduce the end-to-end latency suffered by immersive HMD virtual reality systems. This paper discusses the benefits of using the ARP virtual reality system in addressing security threats and disaster situations

Protecting the Visual Fidelity of Machine Learning Datasets Using QR Codes

Machine learning is becoming increasingly popular in a variety of modern technology. However, research has demonstrated that machine learning models are vulnerable to adversarial examples in their inputs. Potential attacks include poisoning datasets by perturbing input samples to mislead a machine learning model into producing undesirable results. Such perturbations are often subtle and imperceptible from a human\u27s perspective. This paper investigates two methods of verifying the visual fidelity of image based datasets by detecting perturbations made to the data using QR codes. In the first method, a verification string is stored for each image in a dataset. These verification strings can be used to determine whether an image in the dataset has been perturbed. In the second method, only a single verification string stored and is used to verify whether an entire dataset is intact

Cost-effectiveness Analysis of Hospital Infection Control Response to an Epidemic Respiratory Virus Threat

Pandemic (H1N1) 2009 can be contained with less expensive measures than some other viruses