Point cloud data compression

The rapid growth in the popularity of Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) experiences have resulted in an exponential surge of three-dimensional data. Point clouds have emerged as a commonly employed representation for capturing and visualizing three-dimensional data in these environments. Consequently, there has been a substantial research effort dedicated to developing efficient compression algorithms for point cloud data. This Master's thesis aims to investigate the current state-of-the-art lossless point cloud geometry compression techniques, explore some of these techniques in more detail and then propose improvements and/or extensions to enhance them and provide directions for future work on this topic

3D Wavelet Transformation for Visual Data Coding With Spatio and Temporal Scalability as Quality Artifacts: Current State Of The Art

Several techniques based on the three–dimensional (3-D) discrete cosine transform (DCT) have been proposed for visual data coding. These techniques fail to provide coding coupled with quality and resolution scalability, which is a significant drawback for contextual domains, such decease diagnosis, satellite image analysis. This paper gives an overview of several state-of-the-art 3-D wavelet coders that do meet these requirements and mainly investigates various types of compression techniques those exists, and putting it all together for a conclusion on further research scope

Detección de contornos para segmentar fondo y figura en imágenes de resonancia magnética (MRI)

En el área del procesamiento digital de imágenes médicas, varias aplicaciones requieren la separación del fondo de la figura. Una de ellas es la compresión de las imágenes, que es sumamente importante para disminuir a la vez costos de almacenamiento y tiempos de transmisión, facilitando así las tareas de teledetección. En el caso de secuencias de imágenes de resonancia magnética, la figura contiene la información que es relevante para el diagnóstico. Después de separar el fondo de la figura, se descarta el fondo y se aplican técnicas de compresión sin pérdida a la figura. Para ello es indispensable contar con un método de segmentación automática que sea robusto. En este trabajo proponemos utilizar una variante de la segmentación por conjuntos de nivel. A partir de un contorno inicial arbitrario en los tres ejes dimensionales de la imagen, se obtiene la máscara en forma iterativa. Este método ha demostrado ser robusto frente al ruido de la imagen.Sociedad Argentina de Informática e Investigación Operativ

Deep Learning Based Point Cloud Processing and Compression

Title from PDF of title page, viewed August 24, 2022Dissertation advisors: Zhu Li and Sejun SongVitaIncludes bibliographical references (pages 116-137)Dissertation (Ph.D)--Department of Computer Science & Electrical Engineering. University of Missouri--Kansas City, 2022A point cloud is a 3D data representation that is becoming increasingly popular. Recent significant advances in 3D sensors and capturing techniques have led to a surge in the usage of 3D point clouds in virtual reality/augmented reality (VR/AR) content creation, as well as 3D sensing for robotics, smart cities, telepresence, and automated driving applications. With an increase in point cloud applications and improved capturing technologies, we now have high-resolution point clouds with millions of points per frame. However, due to the large size of a point cloud, efficient techniques for the transmission, compression, and processing of point cloud content are still widely sought. This thesis addresses multiple issues in the transmission, compression, and processing pipeline for point cloud data. We employ a deep learning solution to process 3D dense as well as sparse point cloud data for both static as well as dynamic contents. Employing deep learning on point cloud data which is inherently sparse is a challenging task. We propose multiple deep learning-based frameworks that address each of the following problems: Point Cloud Compression Artifact Removal. V-PCC is the current state-of-the-art for dynamic point cloud compression. However, at lower bitrates, there are unpleasant artifacts introduced by V-PCC. We propose a deep learning solution for V-PCC artifact removal by leveraging the direction of projection property in V-PCC to remove quantization noise. Point Cloud Geometry Prediction. The current point cloud lossy compression and processing techniques suffer from quantization loss which results in a coarser sub-sampled representation of the point cloud. We solve the problem of points lost during voxelization by performing geometry prediction across spatial scales using deep learning architecture. Point Cloud Geometry Upsampling. Loss of details and irregularities in point cloud geometry can occur during the capturing, processing, and compression pipeline. We present a novel geometry upsampling technique, PU-Dense, which can process a diverse set of point clouds including synthetic mesh-based point clouds, real-world high-resolution point clouds, real-world indoor LiDAR scanned objects, as well as outdoor dynamically acquired LiDAR-based point clouds. Dynamic Point Cloud Interpolation. Dense photorealistic point clouds can depict real-world dynamic objects in high resolution and with a high frame rate. Frame interpolation of such dynamic point clouds would enable the distribution, processing, and compression of such content. We also propose the first point cloud interpolation framework for photorealistic dynamic point clouds. Inter-frame Compression for Dynamic Point Clouds. Efficient point cloud compression is essential for applications like virtual and mixed reality, autonomous driving, and cultural heritage. We propose a deep learning-based inter-frame encoding scheme for dynamic point cloud geometry compression. In each case, our method achieves state-of-the-art results with significant improvement to the current technologies.Introduction -- Point cloud compression artifact removal -- Point cloud geometry prediction -- PU-Dense: sparse tensor-based point cloud geometry upsampling -- Dynamic point cloud interpolation -- Inter-frame compression for dynamic point cloud geometry codin

Visual Data Representation using Context-Aware Samples

The rapid growth in the complexity of geometry models has necessisated revision of several conventional techniques in computer graphics. At the heart of this trend is the representation of geometry with locally constant approximations using independent sample primitives. This generally leads to a higher sampling rate and thus a high cost of representation, transmission, and rendering. We advocate an alternate approach involving context-aware samples that capture the local variation of the geometry. We detail two approaches; one, based on differential geometry and the other based on statistics. Our differential-geometry-based approach captures the context of the local geometry using an estimation of the local Taylor's series expansion. We render such samples using programmable Graphics Processing Unit (GPU) by fast approximation of the geometry in the screen space. The benefits of this representation can also be seen in other applications such as simulation of light transport. In our statistics-based approach we capture the context of the local geometry using Principal Component Analysis (PCA). This allows us to achieve hierarchical detail by modeling the geometry in a non-deterministic fashion as a hierarchical probability distribution. We approximate the geometry and its attributes using quasi-random sampling. Our results show a significant rendering speedup and savings in the geometric bandwidth when compared to current approaches

Recent Advances in Signal Processing

The signal processing task is a very critical issue in the majority of new technological inventions and challenges in a variety of applications in both science and engineering fields. Classical signal processing techniques have largely worked with mathematical models that are linear, local, stationary, and Gaussian. They have always favored closed-form tractability over real-world accuracy. These constraints were imposed by the lack of powerful computing tools. During the last few decades, signal processing theories, developments, and applications have matured rapidly and now include tools from many areas of mathematics, computer science, physics, and engineering. This book is targeted primarily toward both students and researchers who want to be exposed to a wide variety of signal processing techniques and algorithms. It includes 27 chapters that can be categorized into five different areas depending on the application at hand. These five categories are ordered to address image processing, speech processing, communication systems, time-series analysis, and educational packages respectively. The book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity

Robust density modelling using the student's t-distribution for human action recognition

The extraction of human features from videos is often inaccurate and prone to outliers. Such outliers can severely affect density modelling when the Gaussian distribution is used as the model since it is highly sensitive to outliers. The Gaussian distribution is also often used as base component of graphical models for recognising human actions in the videos (hidden Markov model and others) and the presence of outliers can significantly affect the recognition accuracy. In contrast, the Student's t-distribution is more robust to outliers and can be exploited to improve the recognition rate in the presence of abnormal data. In this paper, we present an HMM which uses mixtures of t-distributions as observation probabilities and show how experiments over two well-known datasets (Weizmann, MuHAVi) reported a remarkable improvement in classification accuracy. © 2011 IEEE

Artificial Intelligence in the Creative Industries: A Review

This paper reviews the current state of the art in Artificial Intelligence (AI) technologies and applications in the context of the creative industries. A brief background of AI, and specifically Machine Learning (ML) algorithms, is provided including Convolutional Neural Network (CNNs), Generative Adversarial Networks (GANs), Recurrent Neural Networks (RNNs) and Deep Reinforcement Learning (DRL). We categorise creative applications into five groups related to how AI technologies are used: i) content creation, ii) information analysis, iii) content enhancement and post production workflows, iv) information extraction and enhancement, and v) data compression. We critically examine the successes and limitations of this rapidly advancing technology in each of these areas. We further differentiate between the use of AI as a creative tool and its potential as a creator in its own right. We foresee that, in the near future, machine learning-based AI will be adopted widely as a tool or collaborative assistant for creativity. In contrast, we observe that the successes of machine learning in domains with fewer constraints, where AI is the `creator', remain modest. The potential of AI (or its developers) to win awards for its original creations in competition with human creatives is also limited, based on contemporary technologies. We therefore conclude that, in the context of creative industries, maximum benefit from AI will be derived where its focus is human centric -- where it is designed to augment, rather than replace, human creativity

3D multiresolution statistical approaches for accelerated medical image and volume segmentation

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Medical volume segmentation got the attraction of many researchers; therefore, many techniques have been implemented in terms of medical imaging including segmentations and other imaging processes. This research focuses on an implementation of segmentation system which uses several techniques together or on their own to segment medical volumes, the system takes a stack of 2D slices or a full 3D volumes acquired from medical scanners as a data input. Two main approaches have been implemented in this research for segmenting medical volume which are multi-resolution analysis and statistical modeling. Multi-resolution analysis has been mainly employed in this research for extracting the features. Higher dimensions of discontinuity (line or curve singularity) have been extracted in medical images using a modified multi-resolution analysis transforms such as ridgelet and curvelet transforms. The second implemented approach in this thesis is the use of statistical modeling in medical image segmentation; Hidden Markov models have been enhanced here to segment medical slices automatically, accurately, reliably and with lossless results. But the problem with using Markov models here is the computational time which is too long. This has been addressed by using feature reduction techniques which has also been implemented in this thesis. Some feature reduction and dimensionality reduction techniques have been used to accelerate the slowest block in the proposed system. This includes Principle Components Analysis, Gaussian Pyramids and other methods. The feature reduction techniques have been employed efficiently with the 3D volume segmentation techniques such as 3D wavelet and 3D Hidden Markov models. The system has been tested and validated using several procedures starting at a comparison with the predefined results, crossing the specialists’ validations, and ending by validating the system using a survey filled by the end users explaining the techniques and the results. This concludes that Markovian models segmentation results has overcome all other techniques in most patients’ cases. Curvelet transform has been also proved promising segmentation results; the end users rate it better than Markovian models due to the long time required with Hidden Markov models