Boundaries detection and color correction of shadows in color images

The paper under consideration deals with information technology for correction of shadow artifacts on color digital images obtained by taking photos of paintings with the purpose of their reproduction. Appearance of shadow artifacts is caused by different intensity of picture lighting. The problem of shadow detection and subsequent color correction in this area is solved.     

Linear array for spelling correction

This paper introduces a linear array for spelling correction using 15 processors. Many architectures have been proposed to solve similar string correction problems such as speech recognition or nucleic acid sequence computation. It is known that the hypercube, de Bruijn and grid networks contain a Hamiltonian path, a path which contains all the vertices of the network. The execution time of spelling correction on all of these networks is equal. © 1997 John Wiley & Sons, Ltd.     

Pixel distribution shifting color correction for digital color images

This paper is concerned with a proposed color correction method called the Pixel Distribution Shifting Color Correction (PDSCC). This method employs a shifting process on the pixel distribution of a color image to correct its white reference point and ensure the white reference point is achromatic. The proposed method has been tested on numerous types of images which include indoor, outdoor, and underwater images. The qualitative and quantitative analyses have shown ample evidence that the proposed method outperforms some state-of-the-art methods, such as the Grey World, the White Patch and the General Grey World methods. The resultant images are viewed to be more natural and suggest more pleasant visualization without the intervention of the saturation problem.     

Spectral characterization and color correction of display colorimeters

Abstract— Tristimulus colorimeters commit systematic errors due to their imperfect realization of the CIE color‐matching functions. A method is proposed to characterize display colorimeters in a single session using a monochromator independently of any display. Colorimeter spectral responsivity functions are obtained that then serve to predict correction matrices for all the possible displays. Experiments show that this can be done with sufficient accuracy to meet practical requirements.     

Automatic color correction for multi-projector display systems

A hierarchical color correction framework is presented to automatically calibrate multiple projectors. The proposed framework consists of two sub-methods: a simple color correction method and an advanced color correction method. An automatic selection scheme is designed to choose between the two sub-methods according to specific conditions. The simple color correction method uses a parameter model to map projected images into the Common Achievable Response (CAR) space for color consistent outputs. The advanced color correction method takes the projector properties, the display surface optical properties, and the relative distances between the screen and the projectors into consideration. A pre-processing step is designed to eliminate isolated abnormal sampling points, resulting in better quality outputs. In the experiment part, the effectiveness of the proposed framework is verified with both front projection systems and rear projection systems. The experimental results show that the proposed framework achieves better calibration results comparing with traditional methods.     

Robust estimating equations and bias correction of correlation parameters for longitudinal data

The estimation of correlation parameters has received attention for both its own interest and improvement of the estimation efficiency of mean parameters by the generalized estimating equations (GEE) approach. Many of the well-established methods for the estimation of correlation parameters can be constructed under the GEE framework which is, however, sensitive to outliers. In this paper, we consider two ways of constructing robust estimating equations for achieving robust estimation of the correlation parameters. Furthermore, the estimators of the correlation parameters from the robustified GEE may be still biased as the expectation of the estimating equation is biased from zero when the underlying distribution is not symmetric. Therefore, bias-corrected robust estimators of correlation parameters are proposed. The performance of the proposed methods are investigated by simulation. The results show that the proposed robust and bias-corrected robust estimators can reduce the bias successfully. Two real data sets are analyzed for illustration.     

利用颜色滤波阵列特性和模糊估计检测篡改

由于有功能强大的计算机和图像处理软件的存在,普通用户可以将数字图像篡改成他们想得到的任何形式.如果这些篡改图用在媒体或法律上,对社会将造成很大的影响,所以检测数字篡改变成了一个非常严峻的问题.在大多数情况下,数字篡改图像是很逼真的,但是在处理过程中也会留下一些痕迹.将图像的颜色滤波阵列特性和模糊估计的方法结合起来对图像进行篡改检测,对多幅图像操作,实验证明有不错的检测效果.     

Application of underwater hyperspectral data for color correction purposes

Color correction of underwater images has been considered a difficult task for a number of reasons. Those include severe absorption of the water column, the unpredictable behavior of light under the water surface, limited access to reliable data for correction purposes, and the fact that we are only able to process three spectral channels, which is insufficient for most color correction applications. Here, the authors present a method to estimate a hyperspectral image from an RGB image and pointwise hyperspectral data. This is then used to color correct the hyperspectral underwater image and transform it back into RGB color space.     

Simultaneous image color correction and enhancement using particle swarm optimization

Color images captured under various environments are often not ready to deliver the desired quality due to adverse effects caused by uncontrollable illumination settings. In particular, when the illuminate color is not known a priori, the colors of the objects may not be faithfully reproduced and thus impose difficulties in subsequent image processing operations. Color correction thus becomes a very important pre-processing procedure where the goal is to produce an image as if it is captured under uniform chromatic illumination. On the other hand, conventional color correction algorithms using linear gain adjustments focus only on color manipulations and may not convey the maximum information contained in the image. This challenge can be posed as a multi-objective optimization problem that simultaneously corrects the undesirable effect of illumination color cast while recovering the information conveyed from the scene. A variation of the particle swarm optimization algorithm is further developed in the multi-objective optimization perspective that results in a solution achieving a desirable color balance and an adequate delivery of information. Experiments are conducted using a collection of color images of natural objects that were captured under different lighting conditions. Results have shown that the proposed method is capable of delivering images with higher quality.     

基于长线列探测器的图像非均匀性研究与校正

基于长线列图像探测器的成像系统,其图像的非均匀性往往制约着系统成像的质量.结合线列图像探测器的结构特点,分析了线列图像的非均匀性产生原因,并在此基础上分析了多点校正算法,并提出一种基于图像轮廓提取的图像平滑算法.通过对比处理前后的结果,采用图像轮廓提取的图像平滑算法,在保证图像细节的基础上,能够提高图像的均匀性.     

Process color watermarking: the use of visual masking and dot gain correction

Subtractive-Color-Reproduction is the fundamental mechanism in 4-color process printing, which employs CMYK (cyan, magenta, yellow and black) dots for color reproduction. Watermarks embedded in RGB images are distorted when the image is transformed from what to process color for printing usage. Based on the feature of CMYK color space and human visual system, this paper presents a robust CMYK watermarking algorithm for printing images, which embeds an informative watermark and a structure template signal in DCT domain of the Yellow information channel and DFT domain of the black information channel respectively. The embedded template enables robustness against geometric distortions in the print-scanning process. Another spatial visual mask is proposed to reshape the embedded energy after it is inverted to the spatial domain, which significantly improves the color fidelity and the image quality. In addition, a dot gain compensation model is put forward for color correction. A series of proof tests have been carried out on an offset press, which show that the watermark preserves the fidelity of the image and can be extracted with a high quality; moreover, a remarkable fidelity of color and tones on printed copies is well preserved.     

A parallel computing-in-memory accelerator utilizing FeRAM array with retention loss correction

<正>Artificial intelligence(AI)'s rapid growth sparks demand for hardware beyond von Neumann architectures, limited by memory-power bottlenecks. Computing-in-memory(CIM)resolves this via compute-storage fusion, eliminating data shuttling [1]. Resistive non-volatile memory(NVM) struggles with IR drop and leakage issues, while ferroelectric NVM can naturally overcome these shortcomings.     

基于均匀圆阵的互耦误差校正算法研究

阵元之间的互耦效应严重影响了DOA的估计性能。基于均匀圆阵,提出了一种互耦条件下的波达方向估计和互耦误差自校正算法。利用带状循环矩阵的特性对均匀圆阵的互耦误差建立数学模型,再利用MUSIC算法和迭代法对互耦误差矩阵和波达方向同时进行估计,自校正方法无需任何辅助阵元即可实现两类参数的估计。仿真实验表明,算法很好地解决了均匀圆阵的互耦问题,能够比较准确地估计出波达方向角和互耦误差值。     

基于彩色滤光阵列的近似值估计自适应校正算法

本篇论文提出了一种有效的基于彩色滤波阵列（CFA）图像内插领域的近似值估计自适应校正算法。通过估计领域像素点的性能而自适应的调整并组合权重因子,可以获得比现有的按照感知特性来考虑权重的方法更好的性能。实验结果也显示了这种自适应算法在CFA图像内插中的应用结果。     

Universal demosaicking for imaging pipelines with an RGB color filter array

A universal demosaicking solution appropriate for imaging pipelines employing a red-green-blue (RGB) color filter array (CFA) is introduced. The proposed solution can demosaick a raw, grayscale, CFA sensor image captured by a digital camera equipped with any RGB-CFA currently in use. The solution utilizes a spectral model, an edge-sensing mechanism, and a postprocessor to preserve the coloration and sharpness of the captured image. The framework readably unifies existing demosaicking solutions which differ in design characteristics, performance, and computational efficiency. Simulation studies indicate that the universal demosaicking framework allows for cost-effective camera image processing and produces visually pleasing full-color digital images.     

Color correction of vehicle images during the sequential registration of color channels

An algorithm for the image normalization of moving objects during the sequential registration of color RGB channels has been developed. This algorithm allows many-colored moving objects to be joined and their characteristics to be calculated; it is based on the use of intercommunication between the coordinates, sizes, and orientations of many-colored copies of objects. Mikhail Valer’evich Gashnikov. Born in 1975. Graduated from Samara State Aerospace University (SGAU) in 1998. Received Candidate’s degree in 2002 in technical sciences. Associate Professor at the Department of Geoinformatics, Samara State Aerospace University. Scientific interests include image processing, compression of images, and statistical coding. He is the author of 50 scientific publications, including 21 articles and one monograph (as a coauthor). Member of the Russian Association for Pattern Recognition and Image Analysis. Andrei Vladimirovich Chernov. Born in 1975. Graduated from Samara State Aerospace University (SGAU) in 1998. Received Candidate’s degree in 2004 in technical sciences. Associate Professor at the Department of Geoinformatics, Samara State Aerospace University. Scientific interests include the processing of remote sensing data and image recognition. He is the author of more than 50 scientific publications, including 24 articles and one monograph (as a coauthor). Member of the Russian Association for Pattern Recognition and Image Analysis. Nikolai Viktorovich Chupshev. Born in 1986. Graduated from Samara State Aerospace University (SGAU) in 2008. Scientific interests include image processing and recognition and geoinformatic systems. Has three publications, including one article.     

矢量阵一种简单的相位误差校正方法

分析了矢量水听器阵的阵列流型和误差模型,针对矢量水听器阵列声压和振速通道存在相位误差问题,应用常规波束形成方法和MUSIC方法进行方位估计误差大。并对通道存在估计性能下降的问题,提出了一种简单的相位误差校正方法。利用阵列流型向量在信号子空间的投影,得出存在相位误差的阵列流型向量就是信号子空间的特征值为＂一＂的特征向量,通过与精确的阵列流型向量比较求出矢量阵的相位误差。最后,修正矢量阵的相位误差,得到准确的方位估计能力。通过计算机仿真,验证了算法的可行性和准确性。     

Visually lossless compression for Bayer color filter array using optimized Vector Quantization

Devices using single sensors to capture colour images are cheaper due to high cost of Charge Couple Device (CCD) sensors or Complementary Metal-Oxide Semiconductor (CMOS) sensors. Single sensor devices use Colour Filter Array (CFA) to sample one colour band at every pixel location. Demosaicking process is applied to interpolate the two missing colours from the surrounding. Typically compression is done on the demosaicked images which may not be efficient due to the individual compression of the different colour space. This work investigated compression of raw data before demosaicking and performs demosaicking to reconstruct the R, G, B bands later. A novel Vector Quantization (VQ) technique for encoding the wavelet decomposed image using Modified Artificial Bee Colony (ABC) optimization algorithm is proposed. The proposed technique is compared with Genetic Algorithm based VQ and ABC based quantization and with standard LBG and Lloyd algorithm. Results show higher Peak Signal-to-Noise Ratio (PSNR) indicating better reconstruction.     

基于NCEP数据的地震热红外遥感逐像元分析方法

提出一种以各像元为基本单位、顾及不同地形单元下垫面属性差异、分析震前地表等压面温度变化的逐像元方法。对比分析了2008年3月21日中国西部于田MS7.2地震前的热异常时空演化特征及其与现有方法分析结果的差异,并以2001年11月14日的中国西部昆仑山MS8.1地震为例进行了验证。结果表明所得红外异常与中国西部孕震区活动构造的空间关联较好。基于NCEP的逐像元分析方法是有效的,为揭示孕震过程尤其是临震前区域构造活动提供了新的途径。