Real-world single image super-resolution: A brief review

Single image super-resolution (SISR), which aims to reconstruct a high-resolution (HR) image from a low-resolution (LR) observation, has been an active research topic in the area of image processing in recent decades. Particularly, deep learning-based super-resolution (SR) approaches have drawn much attention and have greatly improved the reconstruction performance on synthetic data. However, recent studies show that simulation results on synthetic data usually overestimate the capacity to super-resolve real-world images. In this context, more and more researchers devote themselves to develop SR approaches for realistic images. This article aims to make a comprehensive review on real-world single image super-resolution (RSISR). More specifically, this review covers the critical publicly available datasets and assessment metrics for RSISR, and four major categories of RSISR methods, namely the degradation modeling-based RSISR, image pairs-based RSISR, domain translation-based RSISR, and self-learning-based RSISR. Comparisons are also made among representative RSISR methods on benchmark datasets, in terms of both reconstruction quality and computational efficiency. Besides, we discuss challenges and promising research topics on RSISR.     

A general framework to study the price‐color relationship in paintings with an application to Mark Rothko rectangular series

We propose a general framework to study the relationship between the price of a painting and its color‐related attributes. To this end we focus on four key aspects: dominant colors, features of the color palette, color harmony, and color emotions. We demonstrate the usefulness of this approach with an example based on Mark Rothko's post‐1950 paintings (the “rectangular” series), and auction data from the 1994 to 2018 period. We identify two distinct price‐color regimes in Rothko's market: (a) [1994‐2005], a period in which prices are explained mainly by the growing popularity of the artist regardless of the color attributes of the paintings sold; and (b) [2006‐2018], a period in which color‐related attributes explain most of the prices. Furthermore, we find that in this second period, the dominant colors and the diversity of the color palette, are by far the most relevant attributes that influence the price; color harmony and color emotions hold almost no explanatory power during this period. Finally, we propose a new metric based on the Herfindahl Index to describe color diversity; this metric seems to be promising at characterizing the effect of the color palette on the price of a painting.     

APP软件性能效率研究

性能效率是APP软件的重要质量属性，但目前缺乏APP软件性能效率的通用模型。分析了APP软件的性能特征，基于ISO/IEC 25010标准提出了APP软件的性能效率模型，定义了APP软件性能效率的子特性和度量指标。基于提出的APP软件性能效率模型，通过实验对APP软件的性能效率进行了度量及相关分析。     

Quantifying co-creative writing experiences

Collaboration with artificial intelligence (AI) is a growing trend even in the field of creativity. This paper examines which quantitative metrics can be used to comparatively analyse human-computer co-creativity with children. To study this question, 24 schoolchildren of age 10–11 wrote a poem with three co-creative poetry writing processes: a human-computer, a human-human, and a human-human-computer process. The computational participant in the processes was an AI-based application called the Poetry Machine. The children were asked to evaluate their user experience with a 5-point Likert-type questionnaire after each writing process and a comparative questionnaire after finishing all processes. The metrics used in the evaluation were immediate fun, long-term enjoyment, creativity, self-expression, outcome satisfaction, ease of starting and finishing writing, quality of ideas and support from others, and ownership.

Significant differences were found in fun, long-term enjoyment, quality of ideas, support, and ownership. The high number of statistically relevant results was enabled by exposing all participants to all writing processes, and the comparative questionnaire. The human-human-computer process was evaluated the best in long-term enjoyment and the human-computer process the weakest in support and idea quality. Creativity and ease of finishing writing turned out to be outlining metrics for the co-creative processes.     

Electrolyte flow optimization and performance metrics analysis of vanadium redox flow battery for large-scale stationary energy storage

Vanadium redox flow battery (VRFB) is the best choice for large-scale stationary energy storage, but its low energy density affects its overall performance and restricts its development. In order to improve the performance of VRFB, a new type of spiral flow field is proposed, and a multi-physics coupling model and performance metrics evaluation system are established to explore the electrolyte distribution characteristics. The results show that the new spiral flow field can effectively improve the uniformity of electrolyte flow and alleviate the phenomenon of local concentration polarization as compared with the traditional serpentine flow field and parallel flow field. Due to the long flow channel and large pressure drop, the system efficiency is low. However, coulombic efficiency, voltage efficiency and energy efficiency are significantly better than the traditional flow fields. Therefore, the novel flow field has obvious advantages in the application of small stacks.     

Comprehensive performance analysis of objective quality metrics for digital holography

Objective quality assessment of digital holograms has proven to be a challenging task. While prediction of perceptual quality of the recorded 3D content from the holographic wavefield is an open problem; perceptual quality assessment from content after rendering, requires a time-consuming rendering step and a multitude of possible viewports. In this research, we use 96 Fourier holograms of the recently released HoloDB database to evaluate the performance of well-known and state-of-the-art image quality metrics on digital holograms. We compare the reference holograms with their distorted versions: (i) before rendering on the real and imaginary parts of the quantized complex-wavefield, (ii) after converting Fourier to Fresnel holograms, (iii) after rendering, on the quantized amplitude of the reconstructed data, and (iv) after subsequently removing speckle noise using a Wiener filter. For every experimental track, the quality metric predictions are compared to the Mean Opinion Scores (MOS) gathered on a 2D screen, light field display and a holographic display. Additionally, a statistical analysis of the results and a discussion on the performance of the metrics are presented. The tests demonstrate that while for each test track a few quality metrics present a highly correlated performance compared to the multiple sets of available MOS, none of them demonstrates a consistently high-performance across all four test-tracks.     

Planning an ecological network of Xiamen Island (China) using landscape metrics and network analysis

Most Chinese municipal governments and urban planners have attempted to conserve and create urban greenspace in response to rapid urbanization. It is a major task for urban landscape planners to construct an effective and harmonious urban ecological network and maintain a sustainable urban development environment. In this paper, the present situation and a recent greenway augment plan of Xiamen Island were assessed using a series of landscape metrics. The results showed that the recent greenway augment plan could improve the present greenway system considerably. The improvements were indicated by decrease in patch density, and increase in total class area and edge density on the patch level, landscape diversity, landscape evenness and landscape connectivity on the landscape level. On the basis of these analyses, a number of alternative planning scenarios were designed by using network analysis methods for improving the ecological network of Xiamen Island. An alternative planning scenario was proposed to decrease the degree of landscape fragmentation, increase the shape complexity of greenway patches and enhance the landscape connectivity. The results indicated that methods which integrate landscape metrics with network analyses could not only quantitatively assess the present situation and the rationality of planning for urban greenway systems, but also facilitate the design of planning scenarios for urban ecological networks, enabling them to meet the principles of conformity, harmony, circulation, safety, diversity and sustainability. The principles and methods of landscape ecology, and the greenway concepts that have originated in the West can be useful for Chinese landscape planning and can be applied to greenway development in China.     

个性化图像美学评价的研究进展与趋势

图像美学评价方法是当前研究的热点问题。图像美学评价分为大众化和个性化两种。大众化图像美学评价主要研究大多数人对图像共同的审美感知评估,而个性化图像美学评价可以针对用户的个性化审美感知进行评估。现有的研究工作主要集中在大众化图像美学评价上,但是由于人们对图像的审美体验具有高度主观性,研究针对特定用户的个性化图像美学评价方法更加符合现实意义。目前研究人员针对个性化图像美学评价展开了相关研究,并取得了一定的研究进展。但是现有的文献中缺少对个性化图像美学评价方法的综述,本文针对个性化图像美学评价的研究进展与趋势进行概述。首先分析图像美学评价的研究现状与发展趋势;然后针对现阶段的个性化图像美学评价模型进行概述,将现有的个性化图像美学评价模型总结为基于协同过滤的模型、基于用户交互的模型和基于审美差异的模型,并分析这3类模型主要的设计思路以及优缺点;最后介绍个性化图像美学评价在精准营销、个性化推荐系统、个性化视觉增强和个性化艺术设计上的应用前景,并指出未来研究工作在主观特性分析和知识驱动建模等方面的发展方向。