视线跟踪技术的图像质量主观数据库构建及其可视化

目的 视线跟踪技术是当前最新的无干扰地获得人类视觉注意力的生物测量方法。将视线跟踪方法的原理其应用于图像质量感知研究,建立了首个基于眼动的图像质量感知数据库XJTU_ETSS。方法 应用单刺激图像质量评价法,在Tobii TX300的眼动平台上对900幅原始和失真图像进行了49人的60 Hz眼动主观测试。对含眼动的失真图像进行了可视化分析,即利用注视图、热图和自动聚类感兴趣区域图分析注意力在失真图像上的分布特点。结果 针对XJTU_ETSS眼动数据特点,利用反映群体视觉注意力共性的热图可视化方法具体对数据库中一组原始图像和其对应的6种失真图像上的热图进行了比较和定性分析,直观地显了原始图像和不同种类失真图像上视觉注意力的分布特征。结论 通过实验结果可知,视线跟踪方法能十分直观地揭示人在主观图像感知过程中的特性,这对于今后建立基于人眼注意力模型的图像客观评价算法,以及更加深入地揭示人类视觉系统的感知机制都有着现实而重要的意义。     

一种扩展VIFB的红外与可见光图像融合基准

红外与可见光图像融合是机器视觉的一个重要领域,在日常生活中应用广泛。近年来,虽然红外与可见光图像融合领域已有多种融合算法,但目前该领域还缺乏能够衡量多种融合算法性能的算法框架和融合基准。在简要概述了红外与可见光图像融合的最新进展后,提出了一种扩展VIFB的红外与可见光图像融合基准,该基准由56对图像、32种融合算法和16种评价指标组成。基于该融合基准进行了大量实验,用来测评所选取的融合算法的性能。通过定性和定量结果分析,确定了性能优良的图像融合算法,并对红外与可见光图像融合领域的未来前景进行了展望。     

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。     

A hardware architecture for real-time image compression using a searchless fractal image coding method

In this paper we present a novel hardware architecture for real-time image compression implementing a fast, searchless iterated function system (SIFS) fractal coding method. In the proposed method and corresponding hardware architecture, domain blocks are fixed to a spatially neighboring area of range blocks in a manner similar to that given by Furao and Hasegawa. A quadtree structure, covering from 32 × 32 blocks down to 2 × 2 blocks, and even to single pixels, is used for partitioning. Coding of 2 × 2 blocks and single pixels is unique among current fractal coders. The hardware architecture contains units for domain construction, zig-zag transforms, range and domain mean computation, and a parallel domain-range match capable of concurrently generating a fractal code for all quadtree levels. With this efficient, parallel hardware architecture, the fractal encoding speed is improved dramatically. Additionally, attained compression performance remains comparable to traditional search-based and other searchless methods. Experimental results, with the proposed hardware architecture implemented on an Altera APEX20K FPGA, show that the fractal encoder can encode a 512 × 512 × 8 image in approximately 8.36 ms operating at 32.05 MHz. Therefore, this architecture is seen as a feasible solution to real-time fractal image compression.

A new fast reversible method for image safe transfer

In this paper a novel reversible method for fast and safe image transfer is proposed. The method combines compression, data hiding and partial encryption of images in a single processing step. The proposed approach can embed data into the image according to the message size and partially encrypt the image and the message without changing the original image content. Moreover, during the same process the image is lossless compressed. Nevertheless, the compression rate depends on the upper bound of message size to embed in the image. The main idea is to decompose the original image into two sub-images and to apply various processes to each sub-image in order to gain space and increase the amount of embedded data. The two sub-images are then scrambled and partially encrypted. The most significant characteristic of the proposed method is the utilization of a single procedure to simultaneously perform the compression, the reversible data hiding and the partial encryption rather than using three separate procedures. Our approach reduces then the computational effort and the required computation time. This method is specially suited for medical images where one can associate the patient diagnostic to the concerned medical image for safe transfer purpose.     

手指静脉图像质量评价

根据手指静脉图像本身的特征,首次提出了手指静脉图像质量评价方法.在分析人类视觉系统(HVS)性能的基础上,将图像有效区域、对比度、位置偏移度、模糊度、信息熵作为评价手指静脉图像质量的参数.并综合分析这些参数,加权获得静脉图像总质量评价函数.实验表明,得到了与主观评价结果相一致的客观评价值.     

Perceptual image quality mutual information assessment metric using of Gabor features

A good objective metric of image quality assessment （IQA） should be consistent with the subjective judgment of human beings. In this paper, a four-stage perceptual approach for full reference IQA is presented. In the first stage, the visual features are extracted by 2-D Gabor filter that has the excellent performance of modeling the receptive fields of simple cells in the primary visual cortex. Then in the second stage, the extracted features are post-processed by the divisive normalization transform to reflect the nonlinear mechanisms in human visual systems. In the third stage, mutual information between the visual features of the reference and distorted images is employed to measure the visual quality. And in the last pooling stage, the mutual information is converted to the final objective quality score. Experimental results show that the proposed metic has a high correlation with the subjective assessment and outperforms other state-of-the-art metrics.     

Perceptual image quality assessment metric using mutual information of Gabor features

A good objective metric of image quality assessment (IQA) should be consistent with the subjective judgment of human beings. In this paper, a four-stage perceptual approach for full reference IQA is presented. In the first stage, the visual features are extracted by 2-D Gabor filter that has the excellent performance of modeling the receptive fields of simple cells in the primary visual cortex. Then in the second stage, the extracted features are post-processed by the divisive normalization transform to reflect the nonlinear mechanisms in human visual systems. In the third stage, mutual information between the visual features of the reference and distorted images is employed to measure the visual quality. And in the last pooling stage, the mutual information is converted to the final objective quality score. Experimental results show that the proposed metic has a high correlation with the subjective assessment and outperforms other state-of-the-art metrics.     

一种新型图像压缩系统的设计

为打破传统的摄像机-采集卡-存储卡为一体的简单采集存储设计模式,实现模拟视频和数字视频双采集及数据压缩、高速传输的新模式,设计了一种以FPGA为控制核心、DSP为图像数据处理中心、IP核的生成与双SDRAM乒乓缓存协同工作为技巧、PCI卡高速传输为手段的图像压缩系统。DSP逻辑编码的改进使图像压缩比得到进一步提高。通过实际测试,图像的压缩比可达26:1;FPGA+DSP+PCI卡的综合使用使处理图像数据的速度提高至少50%,图像转存速率更是达到了38 MB/s。     

一种盲复原图像振铃效应的后处理与质量评价方法

由于图像盲复原过程中先验信息的不足,往往造成复原图像质量不尽如人意,振铃效应就是影响复原图像质量的重要因素之一。振铃效应的存在使得对复原图像的后续处理难于进行,并使得一些图像质量的评价方法失效。针对图像盲复原的特点,提出了一种振铃效应的后处理方法,并基于将振铃与清晰度分别评价的思想,提出了一种复原图像的无参考评价方案。实验证明该去振铃方法简单有效,该复原图像的评价方案也很好地反映了人类的视觉特性。     

A fast fractal image encoding method based on intelligent search of standard deviation

In this paper we present a fast fractal encoding method based on an intelligent search of a Standard Deviation (STD) value between range and domain blocks. First, we describe the basic fractal image compression theory and an improved bit allocation scheme for Jacquin’s Iterated Function System (IFS) parameter. Experimental results show that using a Fixed Scale Parameter (FSP) can shorten encoding time without significantly affecting reconstructed image quality. Second, we present a search algorithm based on the STD introduced by Tong. We enhance Tong’s STD search algorithm by introducing a domain Intelligent Classification Algorithm (ICA) based on STD-classified domain blocks. The domain block search pool is pruned by eliminating multiple domain blocks with similar STD values. We refer to this pruning as the De-Redundancy Method (DRM). The domain search process is adaptive with the range block STD value of interest controlling the size of the domain pool searched. We refer to this process as the Search Number Adaptive Control (SNAC). Finally, we present experimental results showing the efficiency of the proposed method, noting a significant improvement over Tong’s original STD method without significant loss in the reconstructed image quality.     

基于视觉注意机制与区域结构相似度的图像融合质量评价

针对目前图像融合质量客观评价与主观评价结果一致性不高的问题,结合人类视觉注意机制和区域计算方法对EFQI指标进行改进,提出了一种基于视觉注意机制（VAM）与区域结构相似度的图像融合质量评价指标。该指标充分考虑了人类视觉感兴趣区域和人眼对区域信息敏感的特性,使用方差显著图与视觉显著图相结合的加权方法对图像中的显著区域赋予更大的权值,并采用更符合人类视觉特性的区域计算方法求取融合结果图像和源图像在各区域上的结构相似度以评价融合质量。用该指标评价10种不同融合算法的融合结果图像并与主观评价结果进行相关性分析,分析结果表明该方法相比传统的评价指标能更有效地反映融合图像质量,与主观评价结果一致性更高。     

主观评价JPEG与JPEG2000标准的彩色图像最佳压缩比的实验研究

研究压缩图像在显示器上质量主观评价方法,为实现Internet上图像质量主观评价奠定基础。研究包括显示器设置问题;在彩色电视图像质量主观评价ITU-BT500-11标准的基础上,提出静态压缩图像评价指标;收集了标准彩色测试图像并建立图像库。最后使用JPEG与JPEG2000两种压缩标准对具有不同性质的20景彩色图像进行了7种压缩比的有损压缩,并选取10人采用成对比较的视觉心理物理学方法,对压缩图像进行主观评价实验。得出了JPEG标准下彩色图像最佳压缩比范围为20：1~25：1,JPEG2000范围为25：1~30：1,同时实验结果表明,可以通过视觉的方法对不同LCD显示器进行设置,并达到一个大致相同的设置效果。     

可见光与红外图像融合质量评价指标分析

目的 客观评价作为图像融合的重要研究领域,是评价融合算法性能的有力工具。目前,已有几十种不同类型的评价指标,但各应用领域包括可见光与红外图像融合,仍缺少统一的选择依据。为了方便比较不同融合算法性能,提出一种客观评价指标的通用分析方法并应用于可见光与红外图像融合。方法 将可见光与红外图像基准数据集中的客观评价指标分为两类,分别是基于融合图像的评价指标与基于源图像和融合图像的评价指标。采用Kendall相关系数分析融合指标间的相关性,聚类得到指标分组;采用Borda计数排序法统计算法的综合排序,分析单一指标排序和综合排序的相关性,得到一致性较高的指标集合;采用离散系数分析指标均值随不同算法的波动程度,选择充分体现不同算法间差异的指标;综合相关性分析、一致性分析及离散系数分析,总结具有代表性的建议指标集合。结果 在13对彩色可见光与红外和8对灰度可见光与红外两组图像源中,分别统计分析不同图像融合算法的客观评价数据,得到可见光与红外图像融合的建议指标集(标准差、边缘保持度),作为融合算法性能评估的重要参考。相较于现有方法,实验覆盖20种融合算法和13种客观评价指标,并且不依赖主观评价结果。结论...     

医学图像融合方法综述

多模态医学图像能够为医疗诊断、治疗规划和手术导航等临床应用提供更为全面和准确的医学图像描述。由于疾病的类型多样且复杂,无法通过单一模态的医学图像进行疾病类型诊断和病灶定位,而多模态医学图像融合方法可以解决这一问题。融合方法获得的融合图像具有更丰富全面的信息,可以辅助医学影像更好地服务于临床应用。为了对医学图像融合方法的现状进行全面研究,本文对近年国内外发表的相关文献进行综述。对医学图像融合技术进行分类,将融合方法分为传统方法和深度学习方法两类并总结其优缺点。结合多模态医学图像成像原理和各类疾病的图像表征,分析不同部位、不同疾病的融合方法的相关技术并进行定性比较。总结现有多模态医学图像数据库,并按分类对25项常见的医学图像融合质量评价指标进行概述。总结22种基于传统方法和深度学习领域的多模态医学图像融合算法。此外,本文进行实验,比较基于深度学习与传统的医学图像融合方法的性能,通过对3组多模态医学图像融合结果的定性和定量分析,总结各技术领域医学图像融合算法的优缺点。最后,对医学图像融合技术的现状、重难点和未来展望进行讨论。     

高动态范围图像客观质量评价方法

针对当前高动态范围（HDR）图像质量评价方法未考虑图像色度和结构信息的问题,提出了一种新的HDR图像客观质量评价方法。首先,利用HDR-VDP-2.2中的基于视觉感知的模型得到关于亮度与对比度的视觉保真度特征;然后,将HDR图像转换到YIQ彩色空间,对彩色空间中的Y、I、Q通道分别进行处理,求得色度相似度和结构相关度特征;最后,利用支持向量回归（SVR）的方法对特征进行融合,预测得到高动态范围图像质量的客观评价值。实验结果表明,与HDR-VDP-2.2相比,该方法的Pearson相关系数和Spearman等级相关系数分别提升了23.09%和25.34%;均方根误差（RMSE）降低了38.01%。所提出的方法与主观视觉感知具有更高的一致性。     

A new steganographic method for color and grayscale image hiding

In this paper, we present a steganographic method for embedding a color or a grayscale image in a true color image. Three types of secret images can be carried by the proposed method: hiding a color secret image, hiding a palette-based 256-color secret image, and hiding a grayscale image in a true color image. Secret data are protected by the conventional crypto system DES. We compare the image quality and hiding capacity of the proposed method with those of the scheme in Lin et al.’s scheme. According to the experimental results, the image quality of the proposed method is better than that of the Lin et al.’s scheme. In addition, annotation data can be hidden with the secret image in the host image. The hiding capacity of the proposed method is greater than that of other compared schemes. The experimental results show that the proposed method is a secure steganographic method that provides high hiding capacity and good image quality.     

医学影像多尺度压缩传输方法的研究

医学影像数字化后需要的存储量很大且要求的精确度高,为了保证医学影像的使用质量,现在的医学影像在传输时常需采用无损压缩。但是,这样的医学影像传输方法会占用相当大的带宽,也大大降低了传输速度。提出一种对医学影像的感兴趣区域和非感兴趣区域进行多尺度压缩的方法实现有损压缩传输,获得了良好的效果,并且把实验结果与其他方法进行了对比,结果表明该方法可以有效提高压缩率,提高传输速率。     

Research on risk assessment model of subjective and objective integration in manual handling work

The main hazards in the process of manual handling work are triggered by human factors and ergonomics. This study is intended to implement a valid approach to quantitatively evaluate the risk level during manual handling work. A risk assessment model for manual handling workers was proposed based on subjective and objective correlation. A simulation experiment of manual handling process was developed and an ergonomics evaluation method was carried out. The 33-point human joint model of BlazePose neural network and the Rapid Upper Limb Analysis (RULA) method were utilized to determine the risk posture and risk index of the manual handling workers. This study brought together hemodynamic parameters and the score of Borg Rating of Perceived Exertion (RPE) scale and Physical Resources Scale (PRS) to obtain the final comprehensive index of work risk. The results showed that the risk indexes from the three stages of the experiment obtained by RULA method were 3, 4, and 7. And the scores of comprehensive indexes obtained by the risk assessment model were 1.841, 1.900, and 1.987, suggesting that the evaluation model based on subjective and objective correlation had the same ability to determine the risk levels of different handling tasks. Therefore, the risk assessment model proposed in this study verified the effectiveness of the comprehensive evaluation index integrating hemodynamic parameters and subjective evaluation scores.     

一种角膜新生血管图像的分割方法

为了提高眼科外眼病图像的分割效果，提出了一种基于直方图和形态学的分割方法，用于分割角膜新生血管的充血区域和血管像素，分割结果用于定量分析充血面积和充血密度，并给出实验结果和误差讨论。实验结果表明，该方法简单快速，分割效果较好。