P-Buffer: Hidden-line rendering with a dynamic p-buffer

Despite the emergence of highly realistic computer-generated images, line-drawing images are still a common practice in showing the shapes and movements of three-dimensional objects. It is especially true when rendering time is critical in interactive applications such as the modeling and testing stage of computer aided design/manufacturing, computer animation, and virtual reality. Hence much effort has been devoted to provide sufficient information of the displayed objects with the least amount of time. While the techniques that determine visible surfaces in an image-space have the advantages on rendering speed and processable shapes, those that decide visible lines or line segments in an object-space are more suitable for showing hidden lines. The P-buffer algorithm introduced in this paper is a method for rendering line-drawing images with dashed hidden-lines. Being an image-space method, this algorithm preserves the low computational cost and works on a wide range of object shapes; as an extension to the Z-buffer algorithm it, moreover, discloses hidden surfaces by showing them with dashed lines. After a discussion on rendering techniques of line-drawing images, this paper presents this algorithm with pseudocode in C++ programming language and shows some experimental results as well. This image-space algorithm can be used as a compromise approach that reveals the concealed information of hidden-surface-removed views for time-critical rendering

BMAD: Benchmarks for Medical Anomaly Detection

Anomaly detection (AD) is a fundamental research problem in machine learning and computer vision, with practical applications in industrial inspection, video surveillance, and medical diagnosis. In medical imaging, AD is especially vital for detecting and diagnosing anomalies that may indicate rare diseases or conditions. However, there is a lack of a universal and fair benchmark for evaluating AD methods on medical images, which hinders the development of more generalized and robust AD methods in this specific domain. To bridge this gap, we introduce a comprehensive evaluation benchmark for assessing anomaly detection methods on medical images. This benchmark encompasses six reorganized datasets from five medical domains (i.e. brain MRI, liver CT, retinal OCT, chest X-ray, and digital histopathology) and three key evaluation metrics, and includes a total of fourteen state-of-the-art AD algorithms. This standardized and well-curated medical benchmark with the well-structured codebase enables comprehensive comparisons among recently proposed anomaly detection methods. It will facilitate the community to conduct a fair comparison and advance the field of AD on medical imaging. More information on BMAD is available in our GitHub repository: https://github.com/DorisBao/BMA

Robust Stereoscopic Crosstalk Prediction

We propose a new metric to predict perceived crosstalk using the original images rather than both the original and ghosted images. The proposed metrics are based on color information. First, we extract a disparity map, a color difference map, and a color contrast map from original image pairs. Then, we use those maps to construct two new metrics (Vdispc and Vdlogc). Metric Vdispc considers the effect of the disparity map and the color difference map, while Vdlogc addresses the influence of the color contrast map. The prediction performance is evaluated using various types of stereoscopic crosstalk images. By incorporating Vdispc and Vdlogc, the new metric Vpdlc is proposed to achieve a higher correlation with the perceived subject crosstalk scores. Experimental results show that the new metrics achieve better performance than previous methods, which indicate that color information is one key factor for crosstalk visible prediction. Furthermore, we construct a new data set to evaluate our new metrics

A high-level graphics language based on the Graphical Kernel System

Being an application area of programming languages, graphics languages should keep pace with the development of today's programming languages. Data types, structural operations and free layout of statements provide a more effective means of picture generation, i.e., modelling, rendering and viewing. The Graphical Kernel System (GKS), an international standard graphics language since 1984, is specified on a subroutine basis, therefore suffering from the lack of such high-level language features. This thesis investigates and implements the FORTRAN language binding of GKS into a high-level programming language (HL/GKS) by a generated precompiler. The weaknesses and restrictions of GKS and its FORTRAN binding are discussed. The advanced features and functions of HL/GKS are addressed. The graphical syntax and semantics rules of the extended portion of HL/GKS are introduced. It is expected that HL/GKS will have more attractive features and effective productivity for GKS applications compared to the procedure-level GKS system. The input statements of HL/GKS have the capability of picture communication by interactive devices and hence enable the implementation of sophisticated graphical application programs.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

Framework for the symbolic computation of HolorGraphic models

The HolorGraphic Modelling System HGMS is a general computational framework for the algebraic manipulation of complex mathematical models of both physical and non-physical systems. The lack of constraints on the operational algebra in HGMS provides both flexibility and expressive power for manipulating variables and functions. The underlying influence of the HolorGraphic framework is now being independently observed in seemingly unrelated fields of studies, from theoretical physics to the construction and analysis of curves and surfaces in computer aided geometric design. As it takes its own form above and beyond tensor theory, the HolorGraphic framework provides both a consistent mathematical basis of formulation as well as a visual understanding of the object of study. In this article, we illustrate the use of HGMS in the symbolic computation procedures using general holors and show the basic operations on these structures

sketching freeform meshes using graph rotation functions

We present a new approach for sketching free form meshes with topology consistency. Firstly, we interpret the given 2D curve to be the projection of the 3D curve with the minimum curvature. Then we adopt a topology-consistent strategy based o