IR Search Research Articles

Infrared Dim Small Target Detection Based on Nonconvex Constraint with L1–L2 Norm and Total Variation

Infrared dim small target detection has received a lot of attention, because it is a crucial component of the IR search and track systems (IRST). The robust principal component analysis (RPCA) is a common detection framework, which works with poor performance with complex background edges and sparse clutters due to the inappropriate approximation of sparse items. A nonconvex constraint detection method based on the difference between the L1 and L2 (L1–L2) norm and total variation (TV) is presented. The L1–L2 norm is a more accurate sparse item approximation of L0 norm, which can achieve a better description of the sparse item to separate the target from the complex backgrounds. Then, the total variation norm is conducted on the target image to suppress the sparse clutters. The new model is solved using the alternating direction method of multipliers (ADMM) method. Then, the subproblems in the model are tackled by the difference of convex algorithm (DCA) and the Newton conjugate gradient (Newton-CG) solving L1–L2 norm and TV norm, respectively. In the experiment, we conducted experiments on multiple and single target datasets, and the proposed model outperforms the state-of-the-art (SOTA) methods in terms of background suppression and robustness to accurately detect the target. It can achieve a higher true position rate (TPR) with a low false position rate (FPR).

Aircraft visibility in view from below in the long-wave infrared band using infrared cross section.

Aircraft low observables' features are crucial in the long-wave infrared (LW-IR) band, due to imaging sensors used in IR search and track and in the latest generation of IR-guided missiles. Earthshine irradiance on the aircraft bottom surface is an important source; hence, it is derived using data for atmospheric transmission. Emission due to skin-friction heating (important at high εbot) and earthshine reflection (important at low εbot) are compared by a dimensionless ratio for different bottom surface emissivities (εbot). The infrared cross section of aircraft in direct view from below is obtained in the LW-IR band, which shows that aircraft is seen also due to negative contrast.

Dissecting the Different Components of the Modest Accretion Bursts of the Very Young Protostar HOPS 373

Observed changes in protostellar brightness can be complicated to interpret. In our James Clerk Maxwell Telescope (JCMT) Transient Monitoring Survey, we discovered that a young binary protostar, HOPS 373, is undergoing a modest 30% brightness increase at 850 μm, caused by a factor of 1.8–3.3 enhancement in the accretion rate. The initial burst occurred over a few months, with a sharp rise and then a shallower decay. A second rise occurred soon after the decay, and the source is still bright one year later. The mid-IR emission, the small-scale CO outflow mapped with ALMA, and the location of variable maser emission indicate that the variability is associated with the SW component. The near-IR and NEOWISE W1 and W2 emission is located along the blueshifted CO outflow, spatially offset by ∼3 to 4″ from the SW component. The K-band emission imaged by UKIRT shows a compact H2 emission source at the edge of the outflow, with a tail tracing the outflow back to the source. The W1 emission, likely dominated by scattered light, brightens by 0.7 mag, consistent with expectations based on the submillimeter light curve. The signal of continuum variability in K band and W2 is masked by stable H2 emission, as seen in our Gemini/GNIRS spectrum, and perhaps by CO emission. These differences in emission sources complicate IR searches for variability of the youngest protostars.

Virtual Infrared Display on Flexible and Transparent Substrate

AbstractThis study investigates a method of implementing virtual IR images, similar to the IR images of actual objects, on a transparent and flexible substrate. Virtual IR images/videos can be implemented by irradiating the near‐infrared‐to‐long‐wave IR (NIR‐to‐LWIR) conversion film that can emit LWIR after absorbing NIR and quickly converting it to heat energy. Furthermore, IR images/videos that have shapes and colors similar to actual objects can be formed by adjusting the intensity of the LWIR emitted from the NIR‐to‐LWIR conversion film. This IR image implementation technology is expected to be applicable to advanced camouflage technology—technology that can hide objects or cause them to be perceived as different objects—as well as the implementation of a virtual IR environment that can be used to verify the performance of IR cameras and IR search and tracking systems for artificial intelligence robots, autonomous vehicles, and combat equipment.

Term position‐based language model for information retrieval

AbstractTerm position feature is widely and successfully used in IR and Web search engines, to enhance the retrieval effectiveness. This feature is essentially used for two purposes: to capture query terms proximity or to boost the weight of terms appearing in some parts of a document. In this paper, we are interested in this second category. We propose two novel query‐independent techniques based on absolute term positions in a document, whose goal is to boost the weight of terms appearing in the beginning of a document. The first one considers only the earliest occurrence of a term in a document. The second one takes into account all term positions in a document. We formalize each of these two techniques as a document model based on term position, and then we incorporate it into a basic language model (LM). Two smoothing techniques, Dirichlet and Jelinek‐Mercer, are considered in the basic LM. Experiments conducted on three TREC test collections show that our model, especially the version based on all term positions, achieves significant improvements over the baseline LMs, and it also often performs better than two state‐of‐the‐art baseline models, the chronological term rank model and the Markov random field model.

The cocoon emission – an electromagnetic counterpart to gravitational waves from neutron star mergers

Short Gamma-Ray Bursts (SGRBs) are believed to arise from compact binary mergers (either neutron star-neutron star or black hole-neutron star). If so their jets must penetrate outflows that are ejected during the merger. As a jet crosses the ejecta it dissipates its energy, producing a hot cocoon which surrounds it. We present here 3D numerical simulations of jet propagation in mergers' outflows and we calculate the resulting emission. This emission consists of two components: the cooling emission, the leakage of the thermal energy of the hot cocoon, and the cocoon macronova that arises from the radioactive decay of the cocoon's material. This emission gives a brief (~ one hour) blue, wide angle signal. While the parameters of the outflow and jet are uncertain, for the configurations we have considered the signal is bright (~ -14 $-$ -15 absolute magnitude) and outshines all other predicted UV-optical signals. The signal is brighter when the jet breakout time is longer and its peak brightness does not depend strongly on the highly uncertain opacity. A rapid search for such a signal is a promising strategy to detect an electromagnetic merger counterpart. A detected candidate could be then followed by deep IR searches for the longer but weaker macronova arising from the rest of the ejecta.

A near/mid infrared search for ultra-bright submillimetre galaxies: Searching for Cosmic Eyelash Analogues

We present results from a near/mid IR search for submillimetre galaxies over a region of 6230 sq deg. of the southern sky. We used a cross-correlation of the VISTA Hemispheric Survey (VHS) and the WISE database to identify bright galaxies (K_s <= 18.2) with near/mid IR colours similar to those of the high redshift lensed sub-mm galaxy SMM J2135-0102. We find 7 galaxies which fulfill all five adopted near/mid IR colour (NMIRQC) criteria and resemble the SED of the reference galaxy at these wavelengths. For these galaxies, which are broadly distributed in the sky, we determined photometric redshifts in the range z=1.6-3.2. We searched the VHS for clusters of galaxies, which may be acting as gravitational lenses, and found that 6 out of the 7 galaxies are located within 3.5 arcmin of a cluster/group of galaxies. Using the J-K_s vs J sequences we determine photometric redshifts for these clusters/groups in the range z=0.2-0.9. We propose the newly identified sources are ultra-bright high redshift lensed SMG candidates. Follow-up observations in the sub-mm and mm are key to determine the ultimate nature of these objects.

Order effect in interactive information retrieval evaluation: an empirical study

Purpose – The purpose of this paper is to report a study of order effect in interactive information retrieval (IIR) studies. The phenomenon of order effect is well-known, and it is the main reason why searches are permuted (counter-balanced) between test participants in IIR studies. However, the phenomenon is not yet fully understood or investigated in relation to IIR; hence the objective is to increase the knowledge of this phenomenon in the context of IIR as it has implications for test design of IIR studies. Design/methodology/approach – Order effect is studied via partly a literature review and partly an empirical IIR study. The empirical IIR study is designed as a classic between-groups design. The IIR search behaviour was logged and complementary post-search interviews were conducted. Findings – The order effect between groups and within search tasks were measured against nine classic IIR performance parameters of search interaction behaviour. Order effect is seen with respect to three performance parameters (website changes, visit of webpages, and formulation of queries) shown by an increase in activity on the last performed search. Further the theories with respect to motivation, fatigue, and the good-subject effect shed light on how and why order effect may affect test participants’ IR system interaction and search behaviour. Research limitations/implications – Insight about order effect has implications for test design of IIR studies and hence the knowledge base generated on the basis of such studies. Due to the limited sample of 20 test participants (Library and Information Science (LIS) students) inference statistics is not applicable; hence conclusions can be drawn from this sample of test participants only. Originality/value – Only few studies in LIS focus on order effect and none from the perspective of IIR.

Report on CLEF 2015

This is a report on the sixth edition of the Conference and Labs of the Evaluation Forum (CLEF 2015), held in early September 2015, in Toulouse, France. CLEF was a four day event combining a Conference and an Evaluation Forum. The focus of the Conference is "Experimental IR" as carried out in the CLEF Labs and other evaluation forums, it featured keynotes by Greg Greffenstette, Mounia Lalmas, and Doug Oard, and 43 papers have been presented, covering a wide range of topics. There were a total of eight Labs: eHealth, ImageCLEF, LifeCLEF, Living Labs for IR, NEWSREEL, PAN, QA, and Social Book Search, addressing a wide range of tasks, media, languages, and ways to go beyond standard test collections.

Directional support value of Gaussian transformation for infrared small target detection.

Robust small target detection is one of the key techniques in IR search and tracking systems for self-defense or attacks. In this paper we present a robust solution for small target detection in a single IR image. The key ideas of the proposed method are to use the directional support value of Gaussian transform (DSVoGT) to enhance the targets, and use the multiscale representation provided by DSVoGT to reduce the false alarm rate. The original image is decomposed into sub-bands in different orientations by convolving the image with the directional support value filters, which are deduced from the weighted mapped least-squares-support vector machines (LS-SVMs). Based on the sub-band images, a support value of Gaussian matrix is constructed, and the trace of this matrix is then defined as the target measure. The corresponding multiscale correlations of the target measures are computed for enhancing target signal while suppressing the background clutter. We demonstrate the advantages of the proposed method on real IR images and compare the results against those obtained from standard detection approaches, including the top-hat filter, max-mean filter, max-median filter, min-local-Laplacian of Gaussian (LoG) filter, as well as LS-SVM. The experimental results on various cluttered background images show that the proposed method outperforms other detectors.

Optical model of the atmosphere for correcting IR measurements by satellite and ground-based remote sensing systems

The basic principles for constructing an optical model of the atmosphere in a region of Belarus are discussed for use in atmospheric correction of signals detected by satellite and ground-based IR systems. The input data for the model are the near-earth or altitude-integrated optical and meteorological parameters of the atmosphere and the season. These are used to calculate the height distributions of the air temperature, concentrations of atmospheric gases, concentration of aerosols in the troposphere, and the microphysical parameters of background and post-volcanic aerosols in the stratosphere. A set of programs for calculating the spectral transmission of the atmosphere on personal computer is described. The model is compared with ground-based measurements of the spectral transmission along a horizontal path in the atmosphere and satellite-based measurements of the brightness temperature of the atmosphere. An example of the use of these programs to estimate the thresholds for detection of distant objects by IR search and survey systems is described.

Method to estimate infrared and radio-frequency synergy

A method is developed to study the synergism that can exist between horizon search radar and IR search and track (IRST) systems onboard ship under various meteorological conditions within the marine surface layer (<50 m). The method shows that four operational regions can be defined through the effect of the air-sea temperature difference and the air-sea water vapor pressure difference to produce sub- or superrefractive IR and rf propagation. It is also shown that no conditions can exist such that both IR and rf have subrefractive propagation. Applying the method to many meteorological observations shows that the method works quite well; however, it also indicates that there is not necessarily a detection range advantage to having both an optical and a radar system. However, the advantages to having an optical system are not solely dependent on its range performance. The precision with which an optical system can provide target track parameters, its ability to maintain track when radar systems cannot, and its ability to identify targets are synergisms that are quite significant.

Passive ranging using an infrared search and track sensor

We present new techniques for passive ranging with a dual-band IR search and track (IRST) sensor aboard a ship. Three distance estimation methods are described: the atmospheric propagation model, the apparent surface of the target, and target motion analysis (TMA). These methods are tested on the sensor output of real data during cold water trials (CWTs). They are evaluated by comparing with simultaneously obtained radar reference data at the test site. Results of these three passive ranging and three fusion processes, combining the preceding methods, are presented. This demonstrates the effectiveness of IR passive ranging techniques in the anti-air-warfare scenario. Majority voting fusion shows that improvement of the distance estimation is achieved in the CWT scenario when combining these three different methods. A range-error reduction of 41% is obtained, and a typical uncertainty of 5% is at a 8-km distance. During warm water trials (WWTs) the TMA algorithm was adapted to deal with a dynamic environment of the antisurface warfare scenario (ASuW). These WWTs prove that TMA in combination with an IRST system can extend the basic IRST functionality significantly for a dynamic ASuW scenario.

Elicitation purposes and tasks during mediated information search

This paper provides an empirical characterization of elicitation purposes related to search tasks during mediated information retrieval. During retrieval, a human search intermediary consults with an information seeker about their information problem, and then conducts a search on the elicited topic, both elicit information from each other during the mediated search process. Elicitations during 30 mediated IR searches were examined. A total of 1,241 search intermediary elicitations within 17 IR elicitation categories and 485 information seeker elicitations within ten IR elicitations categories were identified. The paper provides an enhanced IR task model, including sub tasks, derived from our empirical findings. The implications of the findings are discussed.

Recognition of Large Structural Fragments of Organic Compounds by Fast Clusterization of IR Search Result Structures

The results of clusterization of structural formulas (molecular graphs) are given for compounds selected by the IR spectroscopy retrieval system. The molecular graphs are described in terms of vectors (full sets of nonisomorphic linked k-vertex fragments). Analysis of the search result (SR) (30 compounds from 100 compounds used as an example) revealed an average of five classes each containing three graphs. For graphs from individual classes, analysis of common subgraphs yielded a large connected fragment of the compound investigated by its IR spectrum (96 cases). Vector description provides fast solution of the problem.

Iron(VI) Seems an Unlikely Explanation for Viking Labeled Release Results

Tsapin et al. (2000, Icarus 147, 68–78) propose the strong oxidant ferrate(VI) to explain the Viking Labeled Release Mars life detection results. However, their data do not support that theory. Further, sensitive IR searches for oxidants on Mars found none, and Viking produced physical evidence against an oxidizing surface. Finally, Tsapin et al. (2000, Icarus 147, 68–78) report no precautions to prevent microbial contamination from confounding their results.

COORDINATION BINDING MODES FOR POLYMERIC CADMIUM DICARBOXYLATE HYDRATE COMPLEXES

Single crystal X-ray crystal diffraction, IR and TGA-DTA data and searches in the Cambridge Structural Database (CSD) have been used to analyze coordination binding modes of Cd(II) in dicarboxylate complexes with anions of different length. The results, discussed in this paper, show that Cd(II) presents a range of coordination geometries. Six, seven and eight coordination with different degrees of departure from regular polyhedra are observed. The length of the ions influences the availability of donor oxygens and induces bidentate, six or four member chelating rings, and monodentate binding, which produces polymerization of different dimensionality.

XML and information retrieval

XML - the eXtensible Markup Language has recently emerged as a new standard for data representation and exchange on the Interact. It is believed that it will become a universal format for data exchange on the Web and that in the near future we will find vast amounts of documents in XML format on the Web. As a result, it has become crucial to address the question of how large collections of XML documents can be sorted and retrieved efficiently and effectively.To date, most work on storing, indexing, querying, and searching documents in XML has stemmed from the database community's work on semi-structured data. An alternative approach, that has received less attention to date, is to view XML documents as a collection of text documents with additional tags and relations between these tags. IR techniques have traditionally been applied to search large sets of textual data and should thus be extended to encode the structure and semantics inherent in XML documents. Integrating IR and XML search techniques will enable more sophisticated search on the structure as well as the content of these documents, while leveraging the success of IR techniques in document similarity ranking and keyword search.The SIGIR workshop on XML and information retrieval was held July 28th, in Athens Greece. The goal of the workshop was to bring together researchers and practitioners interested in XML and IR to discuss and define the most relevant topics in the relation between these two technologies, present recent results, and propose future directions for research. The topics for discussion included:&amp;bull; How to extend IR technologies to search XML documents&amp;bull; How to integrate XML structure in IR indexing structures&amp;bull; How to query XML documents both on content and structure&amp;bull; How to introduce the semantics inherent in XML into the search process&amp;bull; How to adopt database indexing techniques in an IR frameworkThe opening session of the workshop consisted of a survey of search engines for XML documents. This was followed by three technical sessions: query languages, retrieval algorithms, and IR systems for XML documents. The final talk of the day, "Searching Annotated Language Resources in XML", by Nancy Ide was given from the perspective of potential users of XML search systems and opened many topics for discussion. The workshop was concluded with a panel discussion where the panelists outlined their vision of the future of XML search.

Changes in relevance criteria and problem stages in task performance

The objective of this study is to analyse how changes in relevance criteria are related to changes in problem stages during the task performance process. Relevance is understood as a task‐ and process‐oriented user construct. The assessment of relevance is based on both retrieved bibliographical information and the documents acquired and read on the basis of this information. The participants of the study were eleven students who attended a course for one term for preparing a research proposal for the master’s thesis. The students were asked to make an IR search at the beginning, middle and end of the course. Data for describing their understanding of the work task, search goals and tactics as well as relevance assessments were collected during the search sessions. Pre‐ and post‐search interviews were conducted during each session. The students were asked to think aloud during the search session. The transaction logs were captured and the thinking aloud was recorded. Research and search diaries were also collected. The findings support to a certain extent the overall hypotheses that a person’s problem stage during task performance is related to his or her use of relevance criteria in assessing retrieved references and documents. There is a connection between an individual’s changing understanding of his or her task and how the relevance of references and full texts is judged. The more structured the task in the process, the more able the person is to distinguish between relevant and other sources. The relevance criteria of documents changed more than the criteria of references during the process. Moreover, it seems that understanding of topicality varies depending on the phase of the process.

Which IR search system is better for selection of unknown structure analogues?

A method for comparison of spectral search algorithms is proposed. It is based on the evaluation of spectral distance and structural similarity selected from database compounds relative to query compound. Model examples are discussed.