Morphological feature extraction for statistical learning with applications to solar image data

Abstract: Many areas of science are generating large volumes of digital image data. In order to take full advantage of the high-resolution and high-cadence images modern technology is producing, methods to automatically process and analyze large batches of such images are needed. This involves reducing complex images to simple representations such as binary sketches or numerical summaries that capture embedded scientific information. Using techniques derived from mathematical morphology, we demonstrate how to reduce solar images into simple ‘sketch ’ representations and numerical summaries that can be used for statistical learning. We demonstrate our general techniques on two specific examples: classifying sunspot groups and recognizing coronal loop structures. Our methodology reproduces manual classifications at an overall rate of 90 % on a set of 119 magnetogram and white light images of sunspot groups. We also show that our methodology is competitive with other automated algorithms at producing coronal loop tracings and demonstrate robustness through noise simulations. 2013 Wile

Redesigning architecture through photography

Abstract – This paper focuses on the possibility of (re)designing architecture virtually with the help of one of the most important representation tools: Photography. Various digital processes like stitching multiple photos together and mirroring images in image editing software like Photoshop, allow this virtual architecture to take place in virtual environments. Photography can be utilized in the process of ‘constructing’ a new space --that we can call ‘narrative space’-- from an existing spatial body. This narrative space can also be defined as a ‘manufactured metaspace’ which is a space beyond reality and representation: A constructed reality that exists solely in digital realms like Second Life

The macro and the micro

Andreas Gursky is the darling of philosophers and art theorists of all kinds of traditions and denominations. He has been used as a prime example of the return of the sublime in contemporary art, as a trailblazer in the use of the digital manipulation of images in order to represent something abstract and even as a philosopher of perception who makes some subtle point about the nature of visual experience. All of these arguments are based on some or another technological innovation Gursky uses: the size of his photos, their postproduction (often digital) manipulation and their unusually high resolution. The aim of this paper is to shift the emphasis from these arguments on the significance of the new technology in Gursky’s oeuvre to a much more important role technology plays in his works, namely, in their aesthetics

Beyond abstract film: constructivist digital time

The paper reviews aspects of abstract films and the notions of time that occur in them. A series of developments by the author in making various generative digital abstract, or concrete, works are described and compared to film. The generation of the time element of the works described is integral with the generation of images. It is shown how different approaches to dealing with time in the digital context have emerged. In particular, an integrated constructivist approach has built from concepts in abstract film to go beyond cinema in a way that makes significant use of digital media

Axiomatic Digital Topology

The paper presents a new set of axioms of digital topology, which are easily understandable for application developers. They define a class of locally finite (LF) topological spaces. An important property of LF spaces satisfying the axioms is that the neighborhood relation is antisymmetric and transitive. Therefore any connected and non-trivial LF space is isomorphic to an abstract cell complex. The paper demonstrates that in an n-dimensional digital space only those of the (a, b)-adjacencies commonly used in computer imagery have analogs among the LF spaces, in which a and b are different and one of the adjacencies is the "maximal" one, corresponding to 3n\"i1 neighbors. Even these (a, b)-adjacencies have important limitations and drawbacks. The most important one is that they are applicable only to binary images. The way of easily using LF spaces in computer imagery on standard orthogonal grids containing only pixels or voxels and no cells of lower dimensions is suggested

Water drop to metal and water drop to water drop corona discharges

ABSTRACT Water drop corona has been identified by many authors as a major cause of deterioration of silicone rubber high voltage insulation but at this stage there have been no thorough studies made of this phenomenon. In this paper fundamental observations are presented of electrical discharges from water drops, movement of drops, and drop coalescence in the presence of 50 Hz alternating electric fields. Measurements are made both with water drops on metal electrodes and with water drops on the surface of silicone rubber insulation. Comparisons are made of current pulses and atomic emission spectra from previous work by the authors on dry point-plane discharges to provide information about the main types of active species which may cause insulator surface degradation. Visual images of wet electrodes show how water drops can play a part in encouraging flashover. The first reproducible visual images of water drop corona at the triple junction of water air and rubber insulation are presented. The current measurements were captured with a digital oscilloscope sampling at 200 MHz. The time constant of the measuring circuitry was approximately 14 nanoseconds

Toward Parallel Computation of Dense Homotopy Skeletons for nD Digital Objects

An appropriate generalization of the classical notion of abstract cell complex, called primal-dual abstract cell complex (pACC for short) is the combinatorial notion used here for modeling and analyzing the topology of nD digital objects and images. Let D ⊂ I be a set of n-xels (ROI) and I be a n-dimensional digital image.We design a theoretical parallel algorithm for constructing a topologically meaningful asymmetric pACC HSF(D), called Homological Spanning Forest of D (HSF of D, for short) starting from a canonical symmetric pACC associated to I and based on the application of elementary homotopy operations to activate the pACC processing units. From this HSF-graph representation of D, it is possible to derive complete homology and homotopy information of it. The preprocessing procedure of computing HSF(I) is thoroughly discussed. In this way, a significant advance in understanding how the efficient HSF framework for parallel topological computation of 2D digital images developed in [2] can be generalized to higher dimension is made.Ministerio de Economía y Competitividad TEC2016-77785-PMinisterio de Economía y Competitividad MTM2016-81030-

Comparison of forest attributes derived from two terrestrial lidar systems.

Abstract Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences between scanners in estimates of effective plant area index were greater than differences between sites. Both scanners provided a detailed digital model of forest structure, and gross structural characterizations (including crown dimensions and position) were relatively robust; but comparison of canopy density metrics may require consideration of scanner attributes

radiomic features for medical images tamper detection by equivalence checking

Abstract Digital medical images are very easy to be modified for illegal purposes. An attacker may perform this act in order to stop a political candidate, sabotage research, commit insurance fraud, perform an act of terrorism, or even commit murder. Between the machine that performs medical scans and the radiologist monitor, medical images pass through different devices: in this chain an attacker can perform its malicious action. In this paper we propose a method aimed to avoid medical images modifications by means of equivalence checking. Magnetic images are represented as finite state automata and equivalence checking is exploited to check whether the medical resource have been subject to illegal modifications