基于计算机视觉的图像多尺度识别方法

针对图像识别中图像尺寸比例不一致、旋转角度不相同,以及识别率低、鲁棒性差的问题,提出一种图像的形态学识别算法。首先对图像进行中心化及归一化处理,同时将图形的轮廓图像转换为二值图像;其次采用大小变化的圆形进行图像过滤,获取图形不同尺寸的形态学特征,建立扇形区域特征向量;最后采用多尺度的分析方法进行图像识别以及图像角度分析。在角度无关性、比例无关性、轮廓干扰鲁棒性下与传统方法进行对比实验,实验结果表明该方法有较高的识别率,并可以分析出图像间的角度差值,在图像轮廓有噪声的情况下有较好的鲁棒性,同时大大降低了图像尺寸比例不同、旋转角度不同对图像识别的影响。     

遥感图像目标识别的并行处理方法

为提高遥感图像目标识别的速度，减少消耗的时间，提出了一种特殊的遥感图像目标识别的并行处理方法。基于这种方法，只需对串行识别算法做较少的改动即可实现遥感图像目标识别的并行化处理，无需设计专门的并行识别算法，以较低的代价解决了遥感图像目标识别耗时较多的问题。     

基于感知视觉重要性的立体图像质量评价

视觉心理、生理因素是有效、准确评价图像质量的重要依据.尽管在计算层面已有众多视觉心理、生理计算模型及方法为其提供支持,但在图像质量评价任务中如何分析各种孤立方法之间的内在关系进而使之有效协同,是使得评价结果更符合人主观评测的关键.从图像质量评价的角度出发,功能上将人眼的视觉注意区域定义并数学形式化为视觉初期注意区域与视觉转移期的劣质区域;同时考虑人眼的感知冗余特性,结合JND感知冗余模型,进而提出了图像质量评价范畴下的视觉感知模型PVSSIM.以此为依据,将感知视觉的方法在二维图像数据库中验证其可行性,并将其引入到立体图像质量评价中.实验结果表明,提出的客观评价方法与传统方法相比,充分考虑到了图像质量评价任务中各种视觉心理、生理因素的协同,与人主观的图像质量评价相比具有更高的相关度,评价方法在立体图像库中能很好地与主观评价相吻合,达到了预期的效果.     

机器视觉技术在荔枝识别与定位研究中的应用

为解决串型荔枝图像识别和定位问题,提出以Harris与SIFT算法融合的采摘点计算与匹配为基础,进行平行双目立体视觉模型下采摘点定位的研究方案。首先对荔枝YCbCr色彩空间的Cr灰度图进行二次阈值分割,分类识别出荔枝串、荔枝果与结果母枝。其次,提取识别果实区域的最小外接矩形、质心等特征信息,结合在结果母枝上检测的Harris特征点计算出采摘点的二维图像坐标,并对计算采摘点进行基于SIFT向量搜索的立体匹配。最后,对计算采摘点进行视觉定位及其深度误差分析实验,实验数据表明：在354~590?mm距离范围内,插值补偿后的采摘点的定位深度误差小于10?mm,能够较好满足荔枝采摘机器人的现有技术要求。     

面向对象的高分辨率SAR图像处理及应用

目的随着合成孔径雷达(SAR)技术和分辨率的不断提高,越来越多的空间细节呈现在高分辨率SAR影像上。与此同时,SAR图像的数据量越来越大,人们对其应用需求也越来越高,这使得传统的基于像素的SAR处理方法不再适用。面向对象分析技术以像元集合——"对象"为分析单元,为高分辨率遥感图像处理提供了有效的思路,并日渐成为遥感、摄影测量以及GIS等领域所关注的对象和研究热点之一。目前该技术在光学遥感中已经得到了广泛的应用,但在SAR图像处理中的应用还处于起步阶段。方法本文在简要阐述面向对象分析技术起源和特点的基础上,对SAR图像面向对象技术中常用的多尺度分割算法进行了分类分析,接着对面向对象技术在SAR遥感的应用方向进行全面介绍,最后对面向对象技术在SAR上的应用进行了总结与展望。结果面向对象分析技术在SAR图像处理中的应用主要分为以下五个方面:地物分类、城市信息提取、变化检测、海洋应用、森林应用。结论面向对象分析技术在解决高分辨率SAR图像尺度效应、抑制噪声等方面有着重要作用。目前,国外学者在基于SAR的面向对象分析技术研究上已经取得了一定的进展,但总体上该技术仍面临诸多问题,需要进一步的研究和完善。     

Image processing based automatic recognition of asphalt pavement patch using a metaheuristic optimized machine learning approach

Patch detection is an important task in pavement condition survey. This study establishes an automatic approach for asphalt pavement patch recognition based on image texture analysis and hybrid machine learning algorithms. Features based on image texture that employs statistical properties of color channels and the gray-scale co-occurrence matrix are used by the Least Squares Support Vector Machine (LSSVM) for discriminating patched areas from non-patch ones. In addition, to optimize the LSSVM training phase, the Differential Flower Pollination (DFP) metaheuristic is used. A data set constructed from a set of 1000 image samples has been utilized to train and verify the proposed integration of image texture analysis techniques, LSSVM, and DFP. Experimental results show that the new model can achieve a good prediction result with Classification Accuracy Rate = 95.30%, Positive Predictive Value = 0.96, and the Negative Predictive Value = 0.95. Additionally, a patch detection program has been developed and compiled in Visual C# .NET to ease the implementation of the hybrid model. Thus, the newly developed method can be a potential tool for traffic management agencies during the phase of pavement condition evaluation.     

Digital enhancement of television signals for people with visual impairments: Evaluation of a consumer product

Abstract— Technology to improve the clarity of video for home‐theater viewers is available utilizing a low‐cost enhancement chip (DigiVision DV1000). The impact of such a device on the preference for enhanced video was tested for people with impaired vision and normally sighted viewers. Viewers with impaired vision preferred the enhancement effects more than normally sighted viewers. Preference for enhancement was correlated with loss in contrast sensitivity and visual acuity. Preference increased with increased enhancement settings (designed for those with normal vision) in the group with vision impairments. This suggests that higher enhancement levels may be of even greater benefit, and a similar product could be designed to meet the needs of the large, growing population of elderly television viewers with impaired vision.     

Screen‐based color vision test for digital quantification of deutan color defects using a color‐calibrated monitor

Display technologies are used in various industries. However, few studies on color vision testing using self‐luminous displays are reported. In this study, a screen‐based color vision test, termed the digital color vision test (DCVT), is developed on a color‐calibrated monitor. A control bar is adjusted by the observer to build just noticeable chromatic difference ellipses in CIE u′v′ chromaticity diagram, which indicate the capabilities of subjects' color visions. Ten color‐normal observers and 13 deutan observers participated in the psychophysical experiments. The observers also performed the other two typical diagnostic tests (D‐15 and anomaloscope). Results from the experiment using the adjustment psychophysical method for digital quantification of deutan color vision defects are presented. It is found that the diagnosis accuracy of the DCVT is approximately equivalent to those of D‐15 and anomaloscope tests.     

Embedding of any type of data in images based on a human visual model and multiple-based number conversion

A novel approach to embedding any type of digital data into a cover image is proposed, which utilizes a human visual model to guarantee that the modification of the cover image is imperceptible. A quantized contrast function based on the model is constructed first. The gray values of each 3×3 sub-image of the cover image are used to compute, using the function, a range of gray levels with the same contrast as that of the central pixel of the sub-image. The embedding process proceeds by replacing the gray value of the central pixel by one of the values in the range. This guarantees that the changes be imperceptible. The data to be embedded is treated as a binary stream and is partitioned into a number of sub-streams. A multiple-base number conversion mechanism is used to convert each sub-stream of data into values which are then embedded in the central pixels of sub-images. The embedded data can be extracted out from the resulting stego-image without referencing the original image. Experimental results show that the proposed method is feasible.     

Image categorization using a semantic hierarchy model with sparse set of salient regions

Image categorization in massive image database is an important problem. This paper proposes an approach for image categorization, using sparse set of salient semantic information and hierarchy semantic label tree （HSLT） model. First, to provide more critical image semantics, the proposed sparse set of salient regions only at the focuses of visual attention instead of the entire scene was formed by our proposed saliency detection model with incorporating low and high level feature and Shotton＇s semantic texton forests （STFs） method. Second, we also propose a new HSLT model in terms of the sparse regional semantic information to automatically build a semantic image hierarchy, which explicitly encodes a general to specific image relationship. And last, we archived image dataset using image hierarchical semantic, which is help to improve the performance of image organizing and browsing. Extension experimefital results showed that the use of semantic hierarchies as a hierarchical organizing frame- work provides a better image annotation and organization, improves the accuracy and reduces human＇s effort.     

Image categorization using a semantic hierarchy model with sparse set of salient regions

Image categorization in massive image database is an important problem. This paper proposes an approach for image categorization, using sparse set of salient semantic information and hierarchy semantic label tree (HSLT) model. First, to provide more critical image semantics, the proposed sparse set of salient regions only at the focuses of visual attention instead of the entire scene was formed by our proposed saliency detection model with incorporating low and high level feature and Shotton’s semantic texton forests (STFs) method. Second, we also propose a new HSLT model in terms of the sparse regional semantic information to automatically build a semantic image hierarchy, which explicitly encodes a general to specific image relationship. And last, we archived image dataset using image hierarchical semantic, which is help to improve the performance of image organizing and browsing. Extension experimental results showed that the use of semantic hierarchies as a hierarchical organizing framework provides a better image annotation and organization, improves the accuracy and reduces human’s effort.     

Development and evaluation of a head-mounted display system based on stereoscopic images and depth algorithms for patients with visual impairment

In this work, we developed a wearable system using a commercial stereoscopic head-mounted display. We compared depth first-then contour (df-tc) and contour first-then depth (cf-td) algorithms in terms of images processed per second rate versus the window size and sweep values. Likewise, we performed a comparison of several edge detection methods in the same terms. The developed technical aid was clinically tested. We evaluated the preferred walking speed and the walking speed with and without the devices during three test circuits. For comparative analysis of anxiety levels, we recorded patients’ heart rate data before, during and after the test. The system has proven its potential for enhancing the patients’ mobility and reducing the level of anxiety related to movement activities.