scholarly journals Adaptive Image Rendering Using a Nonlinear Mapping-Function-Based Retinex Model

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 969
Author(s):  
JongGeun Oh ◽  
Min-Cheol Hong

This paper introduces an adaptive image rendering using a parametric nonlinear mapping-function-based on the retinex model in a low-light source. For this study, only a luminance channel was used to estimate the reflectance component of an observed low-light image, therefore halo artifacts coming from the use of the multiple center/surround Gaussian filters were reduced. A new nonlinear mapping function that incorporates the statistics of the luminance and the estimated reflectance in the reconstruction process is proposed. In addition, a new method to determine the gain and offset of the mapping function is addressed to adaptively control the contrast ratio. Finally, the relationship between the estimated luminance and the reconstructed luminance is used to reconstruct the chrominance channels. The experimental results demonstrate that the proposed method leads to the promised subjective and objective improvements over state-of-the-art, scale-based retinex methods.

2020 ◽  
Author(s):  
Jagriti Mishra ◽  
Takuya Inoue

Abstract. Several studies have implied towards the importance of bed roughness on alluvial cover, besides, several mathematical models have also been introduced to mimic the effect bed roughness may project on alluvial cover. Here, we provide a state of the art review of research exploring the relationship between alluvial cover, sediment supply and bed topography, thereby, describing various mathematical models used to analyse deposition of alluvium. In the interest of analysing the efficiency of various available mathematical models, we performed laboratory-scale experiments and compared the results with various models. Our experiments show that alluvial cover is not merely governed by increasing sediment supply, and, bed topography is an important controlling factor of alluvial cover. Testing experimental results with various theoretical models suggest a fit of certain models for a particular bed topography and inefficiency in predicting higher roughness topography. Three models efficiently predict the experimental observations, albeit their limitations which we discuss here in detail.


Author(s):  
J. Romero ◽  
L. Diago ◽  
J. Shinoda ◽  
I. Hagiwara

People rapidly form impressions from facial appearance, and these impressions affect social decisions. Data-driven, computational models are the best available tools for identifying the source of such impressions. However, the computational models cannot be accepted unless they have passed the tests of validation to ascertain their credibility. In this paper, the condition of the eyes of the person is used to validate the fuzzy rules extracted from the computational models. A simple and effective classifier is proposed to evaluate the closeness of the eyes during the evaluation of a small database of portraits. The experimental results show that closed-eyes can be detected only after the proposed shift of the normalized histogram is applied. Although it is very simple, the proposed classifier can achieve better accuracy than other state of the art classifiers. The relationship between the closeness of the eyes and the evaluation of the subjects is also analyzed.


Author(s):  
Xiaobin Liu ◽  
Shiliang Zhang

Recent works show that mean-teaching is an effective framework for unsupervised domain adaptive person re-identification. However, existing methods perform contrastive learning on selected samples between teacher and student networks, which is sensitive to noises in pseudo labels and neglects the relationship among most samples. Moreover, these methods are not effective in cooperation of different teacher networks. To handle these issues, this paper proposes a Graph Consistency based Mean-Teaching (GCMT) method with constructing the Graph Consistency Constraint (GCC) between teacher and student networks. Specifically, given unlabeled training images, we apply teacher networks to extract corresponding features and further construct a teacher graph for each teacher network to describe the similarity relationships among training images. To boost the representation learning, different teacher graphs are fused to provide the supervise signal for optimizing student networks. GCMT fuses similarity relationships predicted by different teacher networks as supervision and effectively optimizes student networks with more sample relationships involved. Experiments on three datasets, i.e., Market-1501, DukeMTMCreID, and MSMT17, show that proposed GCMT outperforms state-of-the-art methods by clear margin. Specially, GCMT even outperforms the previous method that uses a deeper backbone. Experimental results also show that GCMT can effectively boost the performance with multiple teacher and student networks. Our code is available at https://github.com/liu-xb/GCMT .


2019 ◽  
Vol 2 (1) ◽  
pp. 10402-1-10402-11
Author(s):  
Midori Tanaka ◽  
Takahiko Horiuchi ◽  
Ken’ichi Otani

Abstract A planetarium imitates a starry sky with physical and technical limitations using a dome, projector, and light source. It is widely used for entertainment, and astronomy and physics educations. In our previous study, we investigated the evaluation for faithful reproduction of a star field in a planetarium by performing psychometric experiments with 20 observers for plural projection patterns with different reproduction factors (color, luminance, and size of projected stars). In this study, we investigate the relationship between faithfulness and preference of a star field in a planetarium through a psychometric experiment with 47 observers. The experimental procedure followed the previous study. The rating of faithfulness improved for the projection pattern with a smaller star size. For the preference evaluation, the projection pattern with low luminance significantly lowered the preference rating. The results of the experiment indicate that the preferable star reproduction was different between male and female observers, whereas the faithful star reproduction was not significantly different in the evaluations between male and female observers. The male observers sought a faithful star reproduction as the preferred reproduction. In contrast, the female observers did not feel the faithful star reproduction preferable, and evaluated the more brilliant star reproduction as the preferred reproduction. These results were not dependent on the experience in astronomical observations.


2020 ◽  
Vol 8 (1) ◽  
pp. 33-41
Author(s):  
Dr. S. Sarika ◽  

Phishing is a malicious and deliberate act of sending counterfeit messages or mimicking a webpage. The goal is either to steal sensitive credentials like login information and credit card details or to install malware on a victim’s machine. Browser-based cyber threats have become one of the biggest concerns in networked architectures. The most prolific form of browser attack is tabnabbing which happens in inactive browser tabs. In a tabnabbing attack, a fake page disguises itself as a genuine page to steal data. This paper presents a multi agent based tabnabbing detection technique. The method detects heuristic changes in a webpage when a tabnabbing attack happens and give a warning to the user. Experimental results show that the method performs better when compared with state of the art tabnabbing detection techniques.


2021 ◽  
pp. 026540752110309
Author(s):  
James B. Moran ◽  
Nicholas Kerry ◽  
Jin X. Goh ◽  
Damian R. Murray

How does disease threat influence sexual attitudes and behaviors? Although research on the influence of disease threat on social behavior has grown considerably, the relationship between perceived disease threat and sexual attitudes remains unclear. The current preregistered study (analyzed N = 510), investigated how experimental reminders of disease threat influence attitudes and anticipated future behaviors pertaining to short-term sexual relationships, using an ecologically valid disease prime. The central preregistered prediction was that experimental manipulation of disease threat would lead to less favorable attitudes and inclinations toward sexual promiscuity. Results were consistent with this preregistered prediction, relative to both a neutral control condition and a non-disease threat condition. These experimental results were buttressed by the finding that dispositional variation in worry about disease threat predicted less favorable attitudes and inclinations toward short-term sexual relationships. This study represents the first preregistered investigation of the implications of acute disease threat for sexual attitudes.


Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 325
Author(s):  
Zhihao Wu ◽  
Baopeng Zhang ◽  
Tianchen Zhou ◽  
Yan Li ◽  
Jianping Fan

In this paper, we developed a practical approach for automatic detection of discrimination actions from social images. Firstly, an image set is established, in which various discrimination actions and relations are manually labeled. To the best of our knowledge, this is the first work to create a dataset for discrimination action recognition and relationship identification. Secondly, a practical approach is developed to achieve automatic detection and identification of discrimination actions and relationships from social images. Thirdly, the task of relationship identification is seamlessly integrated with the task of discrimination action recognition into one single network called the Co-operative Visual Translation Embedding++ network (CVTransE++). We also compared our proposed method with numerous state-of-the-art methods, and our experimental results demonstrated that our proposed methods can significantly outperform state-of-the-art approaches.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Changyong Li ◽  
Yongxian Fan ◽  
Xiaodong Cai

Abstract Background With the development of deep learning (DL), more and more methods based on deep learning are proposed and achieve state-of-the-art performance in biomedical image segmentation. However, these methods are usually complex and require the support of powerful computing resources. According to the actual situation, it is impractical that we use huge computing resources in clinical situations. Thus, it is significant to develop accurate DL based biomedical image segmentation methods which depend on resources-constraint computing. Results A lightweight and multiscale network called PyConvU-Net is proposed to potentially work with low-resources computing. Through strictly controlled experiments, PyConvU-Net predictions have a good performance on three biomedical image segmentation tasks with the fewest parameters. Conclusions Our experimental results preliminarily demonstrate the potential of proposed PyConvU-Net in biomedical image segmentation with resources-constraint computing.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Mehdi Srifi ◽  
Ahmed Oussous ◽  
Ayoub Ait Lahcen ◽  
Salma Mouline

AbstractVarious recommender systems (RSs) have been developed over recent years, and many of them have concentrated on English content. Thus, the majority of RSs from the literature were compared on English content. However, the research investigations about RSs when using contents in other languages such as Arabic are minimal. The researchers still neglect the field of Arabic RSs. Therefore, we aim through this study to fill this research gap by leveraging the benefit of recent advances in the English RSs field. Our main goal is to investigate recent RSs in an Arabic context. For that, we firstly selected five state-of-the-art RSs devoted originally to English content, and then we empirically evaluated their performance on Arabic content. As a result of this work, we first build four publicly available large-scale Arabic datasets for recommendation purposes. Second, various text preprocessing techniques have been provided for preparing the constructed datasets. Third, our investigation derived well-argued conclusions about the usage of modern RSs in the Arabic context. The experimental results proved that these systems ensure high performance when applied to Arabic content.


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