Image Morphing Based on Mutual Information and Optimal Mass Transport

©2004 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.DOI: 10.1109/ICIP.2004.1421393Time domain image interpolation, or image morphing, refers to a class of techniques for generating a series of smoothly changing intermediate images between two given related images. In this note, we present a novel approach based on the theory of optimal mass transport, using mutual information (MI) as the similarity measurement. The potential applications also include image registration, compression and coding

An Image Morphing Technique Based on Optimal Mass Preserving Mapping

©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or distribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.DOI: 10.1109/TIP.2007.896637Image morphing, or image interpolation in the time domain, deals with the metamorphosis of one image into another. In this paper, a new class of image morphing algorithms is proposed based on the theory of optimal mass transport. The 2 mass moving energy functional is modified by adding an intensity penalizing term, in order to reduce the undesired double exposure effect. It is an intensity-based approach and, thus, is parameter free. The optimal warping function is computed using an iterative gradient descent approach. This proposed morphing method is also extended to doubly connected domains using a harmonic parameterization technique, along with finite-element methods

On Visualizing Branched Surface: an Angle/Area Preserving Approach

The techniques of surface deformation and mapping are useful tools for the visualization of medical surfaces, especially for highly undulated or branched surfaces. In this thesis, two algorithms are presented for flattened visualizations of multi-branched medical surfaces, such as vessels. The first algorithm is an angle preserving approach, which is based on conformal analysis. The mapping function is obtained by minimizing two Dirichlet functionals. On a triangulated representation of vessel surfaces, this algorithm can be implemented efficiently using a finite element method. The second algorithm adjusts the result from conformal mapping to produce a flattened representation of the original surface while preserving areas. It employs the theory of optimal mass transport via a gradient descent approach. A new class of image morphing algorithms is also considered based on the theory of optimal mass transport. The mass moving energy functional is revised by adding an intensity penalizing term, in order to reduce the undesired "fading" effects. It is a parameter free approach. This technique has been applied on several natural and medical images to generate in-between image sequences.Ph.D.Allen Tannenbaum Committee Chair Anthony J. Yezzi, Committee Member; James Gruden, Committee Member; May D. Wang, Committee Member; Oskar Skrinjar, Committee Membe

Transient morphing and optimal shape design of synthetic and natural active structures

Living organisms often display shape morphing capabilities allowing them to efficiently perform tasks that are fundamental for survival. Understanding the way biological activity is exploited to perform shape changes has a deep impact both on natural sciences and technology, often through a process of reverse engineering. In this thesis, we examine four instances of shape morphing both in synthetic and natural, active structures. In the first Chapter, we analyze the transient shaping of a linear poroelastic plate and investigate how mechanical parameters, strains, and stresses influence the swelling dynamics. We obtain an approximate analytical solution for the case of stress-free evolutions and investigate the effect of stresses in the case of an axisymmetric plate. We show that compressive stresses promote faster swelling with respect to the stress-free case, and vice-versa. In the the second Chapter, we address the question of devising efficient morphing strategies for the attainment of specific shape changes in active structures. We set up an optimal control problem which selects, among the activation patterns producing a prescribed shape change, the one minimizing an objective functional, designed to quantify the complexity of the activation. We provide analytical insights for the case of affine shape changes and, with the aid of numerics, we explore the outcome of different objective functionals in a more general context. Chapter 3 is devoted to the study of active reconfigurations in axons, slender cylindrical structures of neurons, which are responsible for the transmission of electro-chemical signals. Axons are able to actively regulate their thickness trough a contractile coating, named cortex, surrounding the cytoplasm (axoplasm). Here, we develop a continuum model describing the interplay between the cortex contractility and the axoplasm elastic response inherited by a network of microtubules. The validity of our modelling assumptions are supported by an excellent match between numerical simulations and experiments. Finally, in the last Chapter, we develop a teleological model to interpret leaves morphogenesis by accounting for the simultaneous growth of both the venation pattern and the blade. Inspired by previous works in the relevant literature, we develop a continuum model by which leaves growth is driven by a gradient flow maximizing the net power absorbed by the leaf. The numerical solution of the ensuing equations provides preliminary results showing some qualitative agreement with features of existing leaves

Smart Material Wing Morphing for Unmanned Aerial Vehicles.

Morphing, or geometric adaptation to off-design conditions, has been considered in aircraft design since the Wright Brothers’ first powered flight. Decades later, smooth, bio-mimetic shape variation for control over aerodynamic forces still remains elusive. Unmanned Aerial Vehicles are prime targets for morphing implementation as they must adapt to large changes in flight conditions associated with locally varying wind or large changes in mass associated with payload delivery. The Spanwise Morphing Trailing Edge (SMTE) concept is developed to locally vary the trailing edge camber of a wing or control surface, functioning as a modular replacement for conventional ailerons without altering the wing’s spar box. The SMTE design was realized utilizing alternating active sections of Macro Fiber Composites (MFCs) driving internal elastomeric compliant mechanisms and passive sections of anisotropic, elastomeric skin with tailorable stiffness, produced by additive manufacturing. Experimental investigations of the modular design via a new scaling methodology for reduced-span test articles revealed that increased use of more MFCs within the active section did not increase aerodynamic performance due to asymmetric voltage constraints. The comparative mass and aerodynamic gains for the SMTE concept are evaluated for a representative finite wing as compared with a conventional, articulated flap wing. Informed by a simplistic system model and measured control derivatives, experimental investigations identified a reduction in the adaptive drag penalty up to 20% at off-design conditions. To investigate the potential for augmented aeroelastic performance and actuation range, a hybrid multiple-smart material morphing concept, the Synergistic Smart Morphing Aileron (SSMA), is introduced. The SSMA leverages the properties of two different smart material actuators to achieve performance exceeding that of the constituent materials. Utilizing the relatively higher work density and phase transformation of Shape-Memory Alloys combined with the larger bandwidth and conformal bending of MFCs, the resultant design is demonstrated to achieve the desired goals while providing additional control authority at stall and for unsteady conditions through synergistic use of reflex actuation. These advances highlight and motivate new morphing structures for the growing field of UAVs in which adaptation involves advanced compliance tailoring of complex geometry with synergistic actuation of embedded, smart materials.PhDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111533/1/alexmp_1.pd

Morphing and Sampling Network for Dense Point Cloud Completion

3D point cloud completion, the task of inferring the complete geometric shape from a partial point cloud, has been attracting attention in the community. For acquiring high-fidelity dense point clouds and avoiding uneven distribution, blurred details, or structural loss of existing methods' results, we propose a novel approach to complete the partial point cloud in two stages. Specifically, in the first stage, the approach predicts a complete but coarse-grained point cloud with a collection of parametric surface elements. Then, in the second stage, it merges the coarse-grained prediction with the input point cloud by a novel sampling algorithm. Our method utilizes a joint loss function to guide the distribution of the points. Extensive experiments verify the effectiveness of our method and demonstrate that it outperforms the existing methods in both the Earth Mover's Distance (EMD) and the Chamfer Distance (CD).Comment: 8pages, 7 figures, AAAI202

Mathematical Imaging and Surface Processing

Within the last decade image and geometry processing have become increasingly rigorous with solid foundations in mathematics. Both areas are research fields at the intersection of different mathematical disciplines, ranging from geometry and calculus of variations to PDE analysis and numerical analysis. The workshop brought together scientists from all these areas and a fruitful interplay took place. There was a lively exchange of ideas between geometry and image processing applications areas, characterized in a number of ways in this workshop. For example, optimal transport, first applied in computer vision is now used to define a distance measure between 3d shapes, spectral analysis as a tool in image processing can be applied in surface classification and matching, and so on. We have also seen the use of Riemannian geometry as a powerful tool to improve the analysis of multivalued images. This volume collects the abstracts for all the presentations covering this wide spectrum of tools and application domains

Continuous Open Access Special Issue "Aircraft Design": Number 2/2020

Following the successful initial Special Issue on “Aircraft Design (SI-1/2017)”, this is already the second SI “Aircraft Design (SI-2/2020)”. Activities in the past showed that aircraft design may be a field too small to justify its own (subscription-based) journal. A continuous open access special issue may fill the gap. As such, the Special Issue “Aircraft Design” can be a home for all those working in the field who regret the absence of an aircraft design journal. SI-2/2020 contains seven papers; an Editorial: 1.) "Publishing in 'Aircraft Design' with a Continuous Open Access Special Issue" and six Original Research Articles about 2.) Amphibious Aircraft Developments, 3.) Design Space Exploration of Jet Engine Components, 4.) Study of Subsonic Wing Flutter, 5.) Design Optimization of a Blended Wing Body Aircraft, 6.) Discrete Mobile Control Surfaces, 7.) Electro-Impulse De-Icing Systems