- 标题
- 摘要
- 关键词
- 实验方案
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An image thresholding approach based on Gaussian mixture model
摘要： Image thresholding is an important technique for partitioning the image into foreground and background in image processing and analysis. It is difficult for traditional thresholding methods to get satisfactory performance on the noisy and uneven grayscale images. In this paper, we propose an image thresholding approach based on Gaussian mixture model (GMM) to solve this problem. GMM assumes that image is a mixture of two unknown parameters’ Gaussian distributions, which corresponds to foreground and background, respectively. Based on this assumption, we adopt expectation maximization algorithm with a simple initialization strategy to estimate the statistical parameters and utilize Bayesian criteria to generate the binary map. Furthermore, we calculate the posterior probabilities in consideration of neighborhood effect to achieve good performance on noisy and uneven grayscale images. Experimental results conducted on the synthetic and real images demonstrate the effectiveness of the proposed method.
关键词： Image thresholding,Gaussian mixture model,EM algorithm,Neighborhood information
更新于2025-09-23 15:23:52
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A Robust Parameter-free Thresholding Method for Image Segmentation
摘要： In this paper, we presented a new parameter-free thresholding method for image segmentation. In separating an image into two classes, the method employs an objective function that not only maximizes the between-class variance but also the distance between the mean of each class and the global mean of the image. The design of the objective function aims to circumvent the challenge that many existing techniques encounter when the underlying two classes have very different sizes or variances. The advantages of the new method are twofold. First, it is parameter-free, meaning that it can generate consistent results. Second, the new method has a simple form that makes it easy to adapt to different applications. We tested and compared the new method with the standard Otsu method, the maximum entropy method, and the 2D Otsu method on the simulated and real biomedical and photographic images and found that the new method can achieve a more accurate and robust performance.
关键词： histogram,parameter-free thresholding,Segmentation,objective function
更新于2025-09-23 15:23:52
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[IEEE 2018 OCEANS - MTS/IEEE Kobe Techno-Ocean (OTO) - Kobe, Japan (2018.5.28-2018.5.31)] 2018 OCEANS - MTS/IEEE Kobe Techno-Oceans (OTO) - Combining Adaptive Thresholding and Region Filling for Xylene Spills Detection from Ultraviolet Images
摘要： Numerous marine chemical spill accidents have caused enormous damage to the marine ecological environment. Multiple researchers are engaged in providing effective method to detect chemical spill detection. In this paper, we compare the properties between ultraviolet (UV) images and visible images. It turns out that the characteristics of UV images help eliminate the background influence. Then, we develop a new algorithm for segmenting chemical spills from UV imagery. This algorithm, combining adaptive thresholding and region filling, can effectively solve the problem of uneven illumination than the Otsu and FCM algorithms. Moreover, this algorithm does well in time consuming. Experimental results on UV imagery demonstrate that our approach can accurately segment chemical spill without producing too much false alarms.
关键词： region filling,UV images,segmentation,adaptive thresholding,chemical spill
更新于2025-09-23 15:22:29
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Dual tree complex wavelet transform incorporating SVD and bilateral filter for image denoising
摘要： In recent years massive production of digital images increased the need for image denoising. The effect of noise can be removed by using spatial and frequency domain approaches. Discrete Wavelet Transforms (DWT) is a frequency domain approach, which removes the noise by shrinking the wavelet coefficients using simple threshold value. Even though wavelet transform is popularly used in image processing applications, shift variance and poor directional selectivity are the two noteworthy limitations. In order to overcome these limitations, Dual Tree Complex Wavelet Transform (DTCWT) is used for perfect reconstruction of noisy image. A DTCWT incorporating Singular Value Decomposition (SVD) with Frobenius energy correcting factor and bilateral filter for image denoising using bivariate shrinkage function for thresholding the image is proposed in this paper. The denoising performance of the proposed method in terms of PSNR and it indicates that the proposed method outperforms over other existing techniques.
关键词： bilateral filter,SVD,bivariate shrinkage,thresholding technique,wavelet transform,DTCWT,image denoising
更新于2025-09-23 15:22:29
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Automatic Detection of Blood Vessel in Retinal Images Using Vesselness Enhancement Filter and Adaptive Thresholding
摘要： Retinal blood vessels detection and measurement of morphological attributes, such as length, width, sinuosity and corners are very much important for the diagnosis and treatment of different ocular diseases including diabetic retinopathy (DR), glaucoma, and hypertension. This paper presents a integration method for blood vessels detection in fundus retinal images. The proposed method consists of two main steps. The first step is pre-processing of retinal image to improve the retinal images by evaluation of several image enhancement techniques. The second step is vessels detection, the vesselness filter is usually used to enhance the blood vessels. The enhancement filter is designed from the adaptive thresholding of the output of the vesselness filter for vessels detection. The algorithms performance is compared and analyzed on three publicly available databases (DRIVE, STARE and CHASE_DB) of retinal images using a number of measures, which include accuracy, sensitivity, and specificity.
关键词： Blood Vessel Detection,Vesselness Enhancement Filter,Adaptive Thresholding
更新于2025-09-23 15:22:29
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[IEEE 2018 5th International Conference on Systems and Informatics (ICSAI) - Nanjing, China (2018.11.10-2018.11.12)] 2018 5th International Conference on Systems and Informatics (ICSAI) - An Enhanced Lowrank Algorithm for Image Denoising
摘要： There are great breakthroughs in image denoising based on the introduction of sparse representation and low rank theory. Some techniques, including BM3D and SAIST are brought forward and applied to various vision tasks. In this paper, we propose an enhanced SAIST algorithm for image denoising. These improvements are mainly implemented in the following aspects. First, when matching similar blocks, matching results are depended on block distances which affected by noise interference. Thus DCT pre-filtering is introduced before aggregation because it can effectively suppress measurement errors of block distances. Second, the relevance of image patches which affects the singular value thresholding is not considered in sample mean. So a weighted sample mean calculation method is proposed to make the singular value thresholding more adaptive. The experimental results show that this improved algorithm achieves a better performance than the original algorithm in terms of both objective criterion and subjective visual quality.
关键词： self-similarity,pre-filtering,singular value thresholding,low-rank method
更新于2025-09-23 15:22:29
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Comparative appraisal of global and local thresholding methods for binarisation of off-axis digital holograms
摘要： Binary digital and computer-generated holograms are used in a number of digital micromirror device (DMD) applications, including holographic displays, media characterisation, optical encryption, and others. Binarisation is one of the most simple and e?cient methods of hologram compression. In this paper, 12 local and 18 global thresholding techniques of di?erent groups were analysed and compared based on attribute similarity, clustering, entropy, histogram shape, and local adaptive factors. Optically recorded o?-axis digital holograms of di?erent objects were binarised using these methods. The amplitude quality of the obtained reconstructed images was compared using PSNR and SSIM values. The clustering-based methods achieved the highest quality. The results of binarisation by global and local methods were comparable on average.
关键词： Image binarisation,Hologram compression,Thresholding,Digital holography,Digital image processing,Digital micromirror device
更新于2025-09-23 15:21:21
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[Advances in Intelligent Systems and Computing] Image Processing and Communications Challenges 10 Volume 892 (10th International Conference, IP&C’2018 Bydgoszcz, Poland, November 2018, Proceedings) || Video Processing and Analysis for Endoscopy-Based Internal Pipeline Inspection
摘要： Because of the increasing requirements in regards to the pipeline transport regulations, the operators take care to the rigorous application of checking routines that ensure nonoccurrence of leaks and failures. In situ pipe inspection systems such as endoscopy, remains a reliable mean to diagnose possible abnormalities in the interior of a pipe such as corrosion. Through digital video processing, the acquired videos and images are analyzed and interpreted to detect the damaged and the risky pipeline areas. Thus, the objective of this work is to bring a powerful analysis tool for a rigorous pipeline inspection through the implementation of speci?c algorithms dedicated to this application for a precise delimitation of the defective zones and a reliable interpretation of the defect implicated, in spite of the drastic conditions inherent to the evolution of the endoscope inside the pipeline and the quality of the acquired images and videos.
关键词： corrosion detection,video processing,pipeline inspection,thresholding methods,endoscopy
更新于2025-09-23 15:21:01
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Secure Image Compression Approach based on Fusion of 3D Chaotic Maps and Arithmetic Coding
摘要： The advances in digital image processing and communications have created a great demand for real–time secure image transmission over the networks. However, the development of effective, fast and secure dependent image compression encryption systems are still a research problem as the intrinsic features of images such as bulk data capacity and high correlation among pixels hinds the use of the traditional joint encryption compression methods. A new approach is suggested in this paper for partial image encryption compression that adopts chaotic 3D cat map to de-correlate relations among pixels in conjunction with an adaptive thresholding technique that is utilized as a lossy compression technique instead of using complex quantization techniques and also as a substitution technique to increase the security of the cipher image. The proposed scheme is based on employing both of lossless compression with encryption on the most significant part of the image after contourlet transform. However the least significant parts are lossy compressed by employing a simple thresholding rule and arithmetic coding to render the image totally unrecognizable. Due to the weakness of 3D cat map to chosen plain text attack, the suggested scheme incorporates a mechanism to generate random key depending on the contents of the image (context key). Several experiments were done on benchmark images to insure the validity of the proposed technique. The compression analysis and security outcomes indicate that the suggested technique is an efficacious and safe for real time image’s applications.
关键词： Cryptography,Chaotic maps,Joint compression encryption,Contourlet transform,Thresholding,Arithmetic coding
更新于2025-09-23 15:21:01
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A new method of mark detection for software-based optical mark recognition
摘要： Software optical mark recognition (SOMR) is the process whereby information entered on a survey form or questionnaire is converted using specialized software into a machine-readable format. SOMR normally requires input fields to be completely darkened, have no internal labels, or be filled with a soft pencil, otherwise mark detection will be inaccurate. Forms can also have print and scan artefacts that further increase the error rate. This article presents a new method of mark detection that improves over existing techniques based on pixel counting and simple thresholding. Its main advantage is that it can be used under a variety of conditions and yet maintain a high level of accuracy that is sufficient for scientific applications. Field testing shows no software misclassification in 5695 samples filled by trained personnel, and only two misclassifications in 6000 samples filled by untrained respondents. Sensitivity, specificity, and accuracy were 99.73%, 99.98%, and 99.94% respectively, even in the presence of print and scan artefacts, which was superior to other methods tested. A separate direct comparison for mark detection showed a sensitivity, specificity, and accuracy respectively of 99.7%, 100.0%, 100.0% (new method), 96.3%, 96.0%, 96.1% (pixel counting), and 99.9%, 99.8%, 99.8% (simple thresholding) on clean forms, and 100.0%, 99.1%, 99.3% (new method), 98.4%, 95.6%, 96.2% (pixel counting), 100.0%, 38.3%, 51.4% (simple thresholding) on forms with print artefacts. This method is designed for bubble and box fields, while other types such as handwriting fields require separate error control measures.
关键词： Software optical mark recognition,pixel counting,mark detection,print and scan artefacts,simple thresholding
更新于2025-09-23 15:21:01