Real-world image dehazing with improved joint enhancement and exposure fusion

In this work, a single image dehazing method that improves the haze removal capacity of the Joint Contrast Enhancement and Exposure Fusion (CEEF) method with Smoothing-Sharpening Image Filter (SSIF) is presented. In this method, the hazy image is first sharpened with SSIF to obtain a sharper image. In this way, the difference between haze and objects is amplified. Then, the AHE procedure in CEEF is replaced by CLAHE to obtain an enhanced CEEF. The enhanced CEEF is applied to the filtering result to obtain the final dehazed image. Observations demonstrate that the proposed method obtains enhanced results while reducing the amount of haze. The visual and quantitative comparisons between the proposed method and state-of-the-art dehazing methods show that the proposed method has better dehazing performance and has a 50% improvement in terms of the FADE metric compared to the closest result.     

Saliency-based content-aware lifestyle image mosaics

In this paper, a novel content-aware lifestyle image mosaic technique is proposed based on image saliency. The image saliency is used in the whole process of creating mosaics. Firstly, a novel energy map for variable-size tile decomposition is proposed by combining Neighborhood Inhomogeneity Factor and Graph-Based Visual Saliency. The target image is divided into small tiles with variable sizes based on the energy map. Secondly, saliency-weighted image retrieval is introduced to choose the tile images from a certain image database. Different aspect ratio between the tile and the corresponding tile image may lead to obvious distortion. Therefore, before filled into the tile, the chosen tile image is resized by seam carving to change its aspect ratio. At last, color correction is done on the mosaic result to improve the color similarity. Compared with other mosaic methods, the proposed technique creates much better mosaics in visual aspect.     

图像和机器视觉技术概述

图像和机器视觉系统是一项快速发展中的应用技术,介绍了机器视觉系统的组成和基本工作原理,及机器视觉在半导体制造领域中的应用。     

数字图像处理中的偏微分方程方法

图像是获取信息的重要媒介,图像处理技术广泛用于人类生活及社会生产中.偏微分方程是一种数学分析方法,并且它的特性由扩散方向和扩散项决定,这一点对图像处理大为有利.本文综述了近年来受到广泛重视的数字图像处理中的偏微分方程方法.给出了偏微分方程在图像去噪、图像放大、图像分割、图像修复中主要算法的优势及不足,同时给出了我们的改进算法,并展示了实验结果.     

基于边缘信息的图像融合算法研究

为了得到全局色调一致的无缝镶嵌融合图像，文章提出了一种基于边缘信息的图像融合方法。该方法根据融合区域的边缘强度信息，对融合区域进行图像增强处理，进而选取一组区域特征进行自适应动态加权，实现了不同图像在选定区域范围内的融合运算，使得被合成的图像完整、自然。通过两幅图像的融合实验，证明了该算法在边缘上保持良好的视觉效果。     

SMT焊点视觉获取及预处理系统的建立与应用

为研究检测SMT焊点的质量和可靠性的方法，建立了一套SMT焊点视觉获取及预处理系统。该系统由硬件检测装置和相关软件组成，具有视频采集、图像捕捉、图像保存、图像预处理以及图像特征参数分析的功能。该系统可以实时对SMT焊点进行视频采集，可以捕捉图像并进行图像预处理，能够获得SMT焊点三维重构所需的图像。通过对比各种图像滤波算法和增强算法，找到了适合SMT焊点图像的预处理算法。     

新型图像实时采集及处理系统设计

本文研究了新型图像实时采集及处理系统。系统通过对视频格式的转换,降低了图像压缩源,采用H.264算法进行图像压缩,降低传输数据量,保证了远程无线图像传输的实时性和清晰度。     

Single underwater image haze removal with a learning-based approach to blurriness estimation

Underwater images are usually degraded due to light scattering and absorption. To recover the scene radiance of degraded underwater images, a new haze removal method is presented by incorporating a learning-based approach to blurriness estimation with the image formation model. Firstly, the image blurriness is estimated with a linear model trained on a set of selected grayscale images, the average Gaussian images and blurriness images. With the estimated image blurriness, three intermediate background lights (BLs) are computed to obtain the synthesized BL. Then the scene depth is calculated by using the estimated image blurriness and BL to construct a transmission map and restore the scene radiance. Compared with other haze removal methods, haze in degraded underwater images can be removed more accurately with our proposed method. Moreover, visual inspection, quantitative evaluation and application test demonstrate that our method is superior to the compared methods and beneficial to high-level vision tasks.     

Image database TID2013: Peculiarities,results and perspectives

This paper describes a recently created image database, TID2013, intended for evaluation of full-reference visual quality assessment metrics. With respect to TID2008, the new database contains a larger number (3000) of test images obtained from 25 reference images, 24 types of distortions for each reference image, and 5 levels for each type of distortion. Motivations for introducing 7 new types of distortions and one additional level of distortions are given; examples of distorted images are presented. Mean opinion scores (MOS) for the new database have been collected by performing 985 subjective experiments with volunteers (observers) from five countries (Finland, France, Italy, Ukraine, and USA). The availability of MOS allows the use of the designed database as a fundamental tool for assessing the effectiveness of visual quality. Furthermore, existing visual quality metrics have been tested with the proposed database and the collected results have been analyzed using rank order correlation coefficients between MOS and considered metrics. These correlation indices have been obtained both considering the full set of distorted images and specific image subsets, for highlighting advantages and drawbacks of existing, state of the art, quality metrics. Approaches to thorough performance analysis for a given metric are presented to detect practical situations or distortion types for which this metric is not adequate enough to human perception. The created image database and the collected MOS values are freely available for downloading and utilization for scientific purposes.     

Efficient quadtree based block-shift filtering for deblocking and deringing

The existing implementations of block-shift based filtering algorithms for deblocking are hard to achieve good smoothing performance and low computation complexity simultaneously due to their fixed block size and small shifting range. In this paper, we propose to integrate quadtree (QT) decomposition with the block-shift filtering for deblocking. By incorporating the QT decomposition, we can easily find the locations of uniform regions and determine the corresponding suitable block sizes. The variable block sizes generated by the QT decomposition facilitate the later block-shift filtering with low computational cost. In addition, large block based shift filtering can provide better deblocking results because the smoothing range of large blocks spans over the conventional 8 × 8 block size. Furthermore, we extend the proposed QT based block-shifting algorithm for deringing JPEG2000 coded images. Experimental results show the superior performance of our proposed algorithms.     

高品质图像的合成技术

通过对不同摄影条件下图像信息的几何矫正、像素匹配及色彩调整,将多幅图像中的相同信息进行恢复和重建,从而获取高品质图像信息。     

BINet: A binary inpainting network for deep patch-based image compression

Recent deep learning models outperform standard lossy image compression codecs. However, applying these models on a patch-by-patch basis requires that each image patch be encoded and decoded independently. The influence from adjacent patches is therefore lost, leading to block artefacts at low bitrates. We propose the Binary Inpainting Network (BINet), an autoencoder framework which incorporates binary inpainting to reinstate interdependencies between adjacent patches, for improved patch-based compression of still images. When decoding a patch, BINet additionally uses the binarised encodings from surrounding patches to guide its reconstruction. In contrast to sequential inpainting methods where patches are decoded based on previous reconstructions, BINet operates directly on the binary codes of surrounding patches without access to the original or reconstructed image data. Encoding and decoding can therefore be performed in parallel. We demonstrate that BINet improves the compression quality of a competitive deep image codec across a range of compression levels.     

基于局部交叉熵的图像匹配跟踪算法

交叉熵值的大小反映了模板图像与实时图像之间的信息量差异大小,从平均意义上来表征模板图像与实时图像之间的信息量差异量。为了解决机裁成像光电吊舱系统中的图像辐射失真和几何失真问题，提出了基于局部交叉熵的图像匹配跟踪算法。由于交叉熵值最小准则有利于信息量丰富的图像匹配，因此该算法不仅具有抗噪能力，而且具有良好的抗辐射失真和抗几何失真的能力。仿真试验表明：在辐射失真情况下，该算法具有稳健的匹配跟踪能力，适应能力强，是一种很实用的匹配跟踪算法。     

一种新的CT重建法

本文提出一种新的CT重建法非均匀反投影重建法。新方法与通常的均匀反投影重建方法不同,它不是把投影差值均匀地分配给有关象素,而是根据象素的灰度加权系数非均匀地分配投影差值。这种新的重建方法使重建象的质量有明显改善,特别是在投影方向数较少的非完全投影情况下,改善效果更加明显。     

提高数字图像清晰度的研究

本文基于数字图像谱分析,指出由高有效像素数源图像下变换为低有效像素数图像,经传输、记录,再内插成高有效像素数图像显示,较直接传输低有效像素数源图像、再内插成高有效像素数重建图像来显示,可获得更高的清晰度．将这种处理方法和所推荐的上、下变换滤波器用于数字图像系统,可提高图像质量、节约传输带宽或降低记录媒质消耗．     

An efficient framework for image/video inpainting

Image inpainting has been widely applied to many applications, such as restoring corrupted old photos, erasing video logos, concealing errors in a digital video processing system, and so on. However, traditional geometric inpainting methods suffer low efficiency. To tackle this problem, this paper addresses an efficient transform based framework for geometric methods. Given an image, we firstly decompose it, then separately perform restoration process and finally employ Laplacian diffusion function to hold local texture coherence. Experimental results show that the proposed method not only speeds up and enhances the performances of geometric methods, but also obtains a better restoration results compared with the traditional texture and hybrid methods.     

基于智能图像处理技术的车型识别

文章提出了一种应用干视频车型识别系统中的图像预处理方法，该方法对采集到的车辆图像处理后可以得到连续、光滑的边缘图像，与构建的车型库相结合，可以应用干公路车辆车型的检测与识别中。实验表明，识别过程快速、准确率较高。具有一定的参考价值。     

基于低速信道的远程图象监控系统

提出了一种以计算机通信为核心采用图象压缩技术在低速信道（公用电话网，ＤＤＮ）上实现远程图象监控的方案，并进行了系统研制。该系统特别适合于图象的存储与管理，已成功地应用于电话局程控机房的无人值守系统。     

A linear quadtree compression scheme for image encryption

A private key encryption scheme for a two-dimensional image data is proposed in this work. This scheme is designed on the basis of lossless data compression principle. The proposed scheme is developed to have both data encryption and compression performed simultaneously. For the lossless data compression effect, the quadtree data structure is used to represent the image; for the encryption purpose, various scanning sequences of image data are provided. The scanning sequences comprise a private key for encryption. Twenty four possible combinations of scanning sequences are defined for accessing four quadrants, thereby making available 24ⁿ × 4^{n(n − 1)/2} possibilities to encode an image of resolution 2ⁿ × 2ⁿ. The security of the proposed encryption scheme therefore relies on the computational infeasibility of an exhaustive search approach. Three images of 512 × 512 pixels are used to verify the feasibility of the proposed scheme. The testing results and analysis demonstrate the characteristics of the proposed scheme. This scheme can be applied for problems of data storage or transmission in a public network.     

Patch reprojections for Non-Local methods

Since their introduction in image denoising, the family of non-local methods, whose Non-Local Means (NL-Means) is the most famous member, has proved its ability to challenge other powerful methods such as wavelet based approaches or variational techniques. Though simple to implement and efficient in practice, the classical NL-Means algorithm suffers from several limitations: noise artifacts are created around edges and regions with few repetitions in the image are not treated at all. In this paper, we present an easy to implement and time efficient modification of the NL-Means based on a better reprojection from the patches space to the original pixel space, specially designed to reduce the artifacts due to the rare patch effect. We compare the performance of several reprojection schemes on a toy example and on some classical natural images.