Digital Image Processing Theory Research Articles

Human-Autonomous Devices for Finite Element Discrete Element Analysis of Geo Material Based on Digital Image Technology

Based on the theory of digital image processing, geometric vector transformation and the principle of automatic generation of finite element meshes, a finite element-discrete element analysis method for digital image of geotechnical engineering materials is proposed. Combining the digital image technology with the finite element-discrete element method (FDEM) coupling analysis method proposed by Munjiza, a FDEM analysis system is developed to characterize the real heterogeneity of rock mass, which provides a new way to model rock mass and study the fracture mechanism of rock mass from a meso-scopic point of view. With the help of digital image technology, the system obtains the real meso-structure of rock material from the image of rock section. With the help of mature mesh generation technology, it maps it to the FDEM computational grid, thus overcoming the shortcomings of the original FDEM in considering material heterogeneity. Using this system, the Brazilian disk splitting test is simulated numerically, and the real fracture process of granite under load is reproduced. And we examined how transparency and task type influence trustfulness, perceived quality of work during human-autonomous system interaction. The numerical simulation results show that the stress distribution of rock samples considering heterogeneity is asymmetric, and the micro-structure of rock has an important influence on the crack propagation and stress distribution in rock.

Quantitative response of subjective visual recognition to fog concentration attenuation based on image standard deviation

Traffic signs are an essential reminder to drivers and passengers. In the fog environment, the absorption and scattering of water molecules in the propagation medium contribute to the attenuation of beam energy, affect the transmission of visual information, and make people unable to correctly identify traffic information. In this study, we simulated the fog environment in the laboratory, improved the method of defining fog concentration in previous experiments, measured fog concentration with the TSI 8350 EP dust meter, and defined standard deviation based on digital image processing theory to characterize image characteristics. We established a subjective visual evaluation environment in the laboratory, invited participants to participate in subjective evaluation experiments, and obtained the relationship between subjective evaluation and image features in turn. We calculated and obtained the quantitative relationship between subjective evaluation and fog concentration based on the typical time axis of fog concentration and the image's standard deviation. This study's results can enhance people's scientific understanding of the traffic environment, and provide data support for further research.

Research on establishing numerical model of geo material based on CT image analysis

Geotechnical engineering material is a kind of heterogeneous composite material. The stone, mineral, gravel, hole, and crack contained in it have different physical and mechanical properties, and their responses to external forces are very different. For example, stress distribution, crack propagation, and failure mode are closely related to material heterogeneity and microstructure. This paper presents a finite element model method for processing CT images of geotechnical materials by using digital image technology. This paper presents a finite element model method for processing CT images of geotechnical materials by using digital image technology. The theory of digital image processing is applied to geotechnical CT image processing to realize pseudo-color enhancement of CT image, and the histograms of different geotechnical CT numbers are obtained. Canny operator is used to detect the edge of geotechnical CT image, and the binary image of geotechnical microstructure is obtained. According to the color change of pseudo-color enhanced image and CT histogram, the meso-structure and variation of rock and soil can be quantitatively analyzed. The finite element model established by this method can fully consider the heterogeneity of geotechnical materials, especially the effect of void distribution on the mechanical properties of geotechnical materials.

Мethod of radiometric distortion correction of multispectral data for the earth remote sensing

The paper deals with technologies of ground secondary processing of heterogeneous multispectral data. The factors of heterogeneous data include uneven illumination of objects on the Earth surface caused by different properties of the relief. A procedure for the image restoration of spectral channels by means of terrain distortion compensation is developed. The object matter of this paper is to improve the quality of the results during image restoration of areas with large and medium landforms. Methods. Researches are based on the elements of the digital image processing theory, statistical processing of the observation results and the theory of multi-dimensional arrays. Main Results. The author has introduced operations on multidimensional arrays: concatenation and elementwise division. Extended model description for input data about the area is given. The model contains all necessary data for image restoration. Correction method for multispectral data radiometric distortions of the Earth remote sensing has been developed. The method consists of two phases: construction of empirical dependences for spectral reflectance on the relief properties and restoration of spectral images according to semiempirical data. Practical Relevance. Research novelty lies in development of the application theory of multidimensional arrays with respect to the processing of multispectral data, together with data on the topography and terrain objects. The results are usable for development of radiometric data correction tools. Processing is performed on the basis of a digital terrain model without carrying out ground works connected with research of the objects reflective properties.

Evaluations on the Applicability of Generic and Modular Image Processing Chains for Quantitative 3D Data Analysis in Clinical Research and Radiographer Training

The introduction of digital imaging and diagnostics facilities has fundamentally changed radiology. Nevertheless, theory of digital image processing and analysis as well as their practical application are still only a subsidiary part in nowadays radiology technician curricula. This work focuses on the evaluation, to what extent the authors' simplified and standardized process model for applying image processing modules in generic domains is suited for radiographer students and medical staff, lacking deeper theoretical knowledge compared to physicians and imaging experts. The semi-automated image processing workflow thereby comprises region growing, live-wire segmentation and filtering steps, all available from MeVisLab prototyping framework. It is shown that the proposed imaging chain is highly applicable for analysis and facilitating medical diagnostics of arbitrary anatomical structures from tomographic data. After compact practical instruction, radiographer students are versed to achieve complex 3D analysis perfectly suited for quantitative analysis in clinical research typically only achievable by use of specialized software.

Analysis of Distance Measurement System of Leading Vehicle

Based on the digital image processing theory, a new method of measuring the leading vehicle distance was proposed. The input image using the method of edge enhancement and morphological transformation was established, so the edges of objects were enhanced to identify. The target vehicle was identified and calibrated in the image by using the method of the obstacle detection by segmentation and decision tree. The relationship between coordinates value in image space and the data of the real space plane was established by applying the ray angles. Thus, through accessing to image pixel coordinates of the vehicle, the vehicle's actual position in the plane can be calculated. At last, the leading vehicle distance based on the calculating model of inverse perspective mapping was measured. By using software VC++, an experiment program was made. The experiment results prove that the method of measuring the leading vehicle distance is simple and effective. It can meet the requirement of intelligent vehicle technologies. It is an more available and more advanced method to calculate the leading vehicle distance. The target vehicle was identified and calibrated in the image by using the method of the obstacle detection by segmentation and decision tree. The relationship between coordinates value in image space and the data of the real space.

Statistical Macro- and Meso-Damage Study on Marble under Uniaxial Compression Based on SEM Equipment

A meso-mechanical testing scheme based on scanning electron microscopy(SEM) is developed to carry out the experiment of microfracturing process of rocks. The microfracturing process of the sample on surrounding rock in immerged Long-big tunnel in Jinping Cascade II Hydropower Station under uniaxial compression is recorded by using the testing scheme. According to digital image processing theory, the meso-structural information of rock microfracture such as length, angle, area, etc are obtained from SEM images. Then, the meso-structural information of microfracturing process under uniaxial compress is analysized and the distribution regularities of microfracture parameters are generalized extreme value distribution with variable parameters. The process was described of the damage from the perspectives of macro-and micro-scale under the uniaxial compression loads.

Quantification Studies on Meso-Damage Characteristics of Marble under Uniaxial Compression Condition

The damage and failure of rock under loading are caused by the propagation and coalescent of cracks at mesoscale, so it is helpful to understand the mechanical behaviours of rock by quantitatively investigating on mesostructure of rocks. Based on the theory of damage mechanics, a digital experimental system on rock meso-structure is proposed. In this paper, the digital studies are conducted on the meso-structure of the marble from Jinping, Sichuan with the damage theory. Lots of meso-structure images are obtained through SEM observation. Based on digital image processing theory, some meso-level characteristics of micro-cracks are obtained such as length, azimuth, width, area and circumference. With the statistics theory and the Monte Carlo theory, the meso-level information of micro-cracks and their morphology are simulated in the representative volume element (RVE) of the Jinping specimen.

Modeling of micro-crack growth during thermal shock based on microstructural images of thermal barrier coatings

Abstract Based on digital image processing theory and finite element mesh generation principle, a methodology is proposed to model the micro-crack growth of thermal barrier coatings (TBCs) during thermal shock with the aid of finite element program. Firstly, a microstructural image of plasma sprayed TBCs is transferred to digital image; secondly, a finite element grid model is generated by thresholding segmentation according to the actual microstructure; finally, based on the finite element grid model, the Tuler–Butcher failure criterion is employed to model the micro-crack growth of TBCs during thermal shock. The numerical simulation result agrees well with the experimental result, and the methodology presented in this paper is found to be effective to model the micro-crack growth.

TFT-LCD Mura defects automatic inspection system using linear regression diagnostic model

The TFT-LCD panel is one of the most important and promising products in the recent years. Mura defects can be created on the display panel during its production. In this research, a linear regression diagnostic model is incorporated with digital image processing theory to automatically inspect for Mura defects. A bivariate polynomial regression model is used to simulate the brightness of background images that is used in the diagnosis of outliers and influential points. The partitions of the candidate Mura defect regions are segmented using Niblack's threshold criteria. The candidate Mura defects are further evaluated. The quantified level is defined in terms of concepts already reported in the literature. Based on Weber's law and a visual perception model, the just-noticeable intensity difference index of the Mura features can be obtained and it can be subsequently used to quantify the Mura defect level. With the obtained defect level, Mura defects can be identified for exactly labelling of the perfect and imperfect LCD panels. Experiments were performed on 13 TFT-LCD panels. There are ten bad panels and three good panels in these 13 samples as determined by human visual inspection. Each bad panel has at least one Mura defect. After the automated inspection process, the results showed that the proposed method could separate the good and bad panels accurately. Compared with human visual inspection, the Mura detection rate of the distinct size and shapes can attain over 90.9 per cent correct detection and the achieved correction rate of Mura defects on each panel can be improved by 100 per cent.

On shock localization by digital image processing techniques

A general approach is presented to a problem of localization of strong discontinuities in the spatial domain on the basis of numerical solution of multidimensional steady and unsteady problems by finite difference shock-capturing techniques. The essence of the approach is in the use of ideas and methods of the digital image processing theory, in particular, of methods for the detection of edges in the image brightness. The algorithms of localization of strong discontinuities in the difference solutions developed on the above-mentioned basis do not require for their realization any a priori information on the orientation of shock surfaces with respect to the spatial co-ordinates axes. The questions of accuracy of the new localization algorithms and of increasing the accuracy of the numerical solutions with the aid of image restoration techniques are considered. The universality of the proposed algorithms is demonstrated in the examples of computations of a number of model two-dimensional unsteady problems by the Godunov scheme and by the MacCormack scheme.

Technical note. The tutorial image processing system: A tool for remote sensing training

Abstract The Tulorial Image Processing System (TIPS) is an interactive microcomputer program designed to teach fundamental principles of digital image processing theory. It allows students to experiment with the mechanisms of convolution, ratioing, classification, etc. in an environment that preserves the essential features of an image processing system, yet allows users to trace easily the mathematical operations involved. TIPS runs on many microcomputers and requires no special graphics hardware. The program is available from the authors.