In this paper we propose look-up table (LUT) based methods for inverse halftoning of images. The LUT for inverse halftoning is obtained from the histogram gathered from a few sample halftone images ...and corresponding original images. The method is extremely fast (no filtering is required) and the PSNR and visual image quality achieved is comparable to the best methods known for inverse halftoning. The LUT inverse halftoning method does not depend on the specific properties of the halftoning method, and can be applied to any halftoning method. Then, an algorithm for template selection for LUT inverse halftoning is introduced. We demonstrate the performance of the LUT inverse halftoning algorithm on error diffused images and ordered dithered images. We also extend LUT inverse halftoning to color halftones.
Unlike the error diffusion method, the dot diffusion method for digital halftoning has the advantage of pixel-level parallelism. However, the image quality offered by error diffusion is still ...regarded as superior to most of the other known methods. We show how the dot diffusion method can be improved by optimization of the so-called class matrix. By taking the human visual characteristics into account we show that such optimization consistently results in images comparable to error diffusion, without sacrificing the pixel-level parallelism. Adaptive dot diffusion is also introduced and then a mathematical description of dot diffusion is derived. Furthermore, inverse halftoning of dot diffused images is discussed and two methods are proposed. The first one uses projection onto convex sets (POCS) and the second one uses wavelets. Of these methods, the wavelet method does not make use of the knowledge of the class matrix. Embedded multiresolution dot diffusion is also discussed, which is useful for rendering at different resolutions and transmitting images progressively.
Halftoning is the rendition of continuous-tone pictures on displays, paper or other media that are capable of producing only two levels. In digital halftoning, we perform the gray scale to bilevel ...conversion digitally using software or hardware. In the last three decades, several algorithms have evolved for halftoning. Examples of algorithms include ordered dither, error diffusion, blue noise masks, green noise halftoning, direct binary search (DBS), and dot diffusion. In this paper, we first review some of the algorithms which have a direct bearing on our paper and then describe some of the more recent advances in the field. The dot-diffusion method for digital halftoning has the advantage of pixel-level parallelism unlike the error-diffusion method, which is a popular halftoning method. However, the image quality offered by error diffusion is still regarded as superior to most of the other known methods. We first review error diffusion and dot diffusion, and describe a recent method to improve the image quality of the dot-diffusion algorithm which takes advantage of the Human Visual System (HVS) function. Then, we discuss the inverse halftoning problem.
The authors previously proposed a look up table (LUT) based method for inverse halftoning of images. The LUT for inverse halftoning is obtained from the histogram gathered from a few sample halftone ...images and corresponding original images. Many of the entries in the LUT are unused because the corresponding binary patterns hardly occur in commonly encountered halftones. These are called nonexistent patterns. In this paper, we propose a tree structure which will reduce the storage requirements of an LUT by avoiding nonexistent patterns. We demonstrate the performance on error diffused images and ordered dither images. Then, we introduce LUT based halftoning and tree-structured LUT (TLUT) halftoning. Even though the TLUT method is more complex than LUT halftoning, it produces better halftones and requires much less storage than LUT halftoning. We demonstrate how the error diffusion characteristics can be achieved with this method. Afterwards, our algorithm is trained on halftones obtained by direct binary search (DBS). The complexity of TLUT halftoning is higher than the error diffusion algorithm but much lower than the DBS algorithm. Also, the halftone quality of TLUT halftoning increases if the size of the TLUT gets bigger. Thus, the halftone image quality between error diffusion and DBS will be achieved depending on the size of the tree-structure in the TLUT algorithm.
This paper focuses on cell loading and family scheduling in a cellular manufacturing environment. The performance measure is minimising the maximum tardiness of jobs. What separates this study from ...others is the presence of individual due dates for every job in a family and also allowing family splitting among cells. Three methods are examined in order to solve this problem, namely mathematical modelling, genetic algorithms (GA) and heuristics. The results showed that GA is capable of finding the optimal solution with varying frequency of 60-100% and it is efficient as compared to the mathematical modelling especially for larger problems in terms of execution times. The heuristics, on the other hand, were easy to implement but they could not find the optimal solution. The results of experimentation also showed that family splitting was observed in all multi-cell optimal solutions and therefore it can be concluded that family splitting is a good strategy for the problem considered in this paper.
Systematic mediastinal, hilar and interlobar lymph node dissection is required in the S3 guidelines for the treatment of operable lung cancer. The lymph node involvement is considered one of the key ...prognostic factors. The type of lymph node resection is repeatedly the subject of controversially discussion. Lymph node dissection is essential for staging, prognosis, survival and recurrence rate. It should be standardized as a compartmental dissection with en bloc resection of lymph nodes including surrounding fat and connective tissue. Thus, exact knowledge of the anatomy of the thoracic organs with their peculiarities and high anatomical variability is necessary.
CSES (China Seismo-Electromagnetic Satellite) is a Chinese–Italian scientific space mission dedicated to monitor the variations of the main parameters of the topside ionosphere (electric and magnetic ...fields, plasma parameters, charge particle fluxes) caused by either natural emitters – especially earthquakes – or artificial ones.
The CSES satellite was successfully launched from the Jiuquan Satellite Launch Center located in the west of Inner Mongolia on February 2nd, 2018, and it is now orbiting under nominal conditions. The expected mission lifetime amounts to 5 years. CSES is the first element of a multi-satellite monitoring system; several satellites are scheduled for the next few years.
The High-Energy Particle Detector (HEPD) is the main contribution of the Italian collaboration to the mission. It was designed and built in order to detect electrons in the energy range between 3 and 100 MeV, protons between 30 and 200 MeV, and light nuclei in the MeV energy window.
The electronics of the detector was designed following stringent requirements on mechanical and thermal stability, power consumption, radiation hardness and double redundancy. The system successfully went through the space qualification tests. In this paper, we describe the HEPD electronics, the space qualification tests performed before launch, and the in-flight performance of the detector.
Cosmic rays’ interactions with the residual atmosphere surrounding the Earth produce a variety of particles, like electrons, positrons, protons, anti-protons, and Helium nuclei that can be observed ...below the local geomagnetic cutoff. In this work, we present new measurements of downward-going, albedo proton fluxes with kinetic energy in the range ∼40–∼250 MeV, performed by the High-Energy Particle Detector (HEPD-01) on board of the China Seismo-Electromagnetic Satellite - CSES-01 - at an altitude of ∼500 km. Employing a dedicated trajectory-tracing simulation routine, the protons collected by HEPD-01 are classified into quasi-trapped (QT), long lifetime (≳10 s) particles concentrating in the equatorial region of the Earth, and un-trapped (UT), distributed at all latitudes; the latter includes both precipitating short lifetime particles (UTS) and pseudo-trapped long lifetime (UTL) populations, abundant in the so-called penumbra regions. The temporal trend of re-entrant protons between 2018 and 2022 is also reported, assessing the stability of such population during the data-taking period of HEPD-01; this highlights their independence from the long-term modulating effect of the solar activity.
•A study of re-entrant albedo protons in the Earth’s magnetosphere as a function of energy with the HEPD-01 payload is presented.•A comparison with past experiments is carried out, with good results.•Time-profiles of re-entrant albedo protons show a general stability during the analyzed period.
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