Search

Detection of double Joint photographic experts group (JPEG) compression is a major part of image forensics, especially double JPEG compression detection with the same quantization matrix is still a challenging problem. Detection of double JPEG compression for different quantization matrices has achieved good performance so far, and some methods for detecting the same quantization matrix have been proposed. However, most methods designed for grayscale images, where they utilize only truncation and rounding errors, not fully exploiting all the useful information of color JPEG images. In addition, there is no suitable model to analyze the convergence of JPEG images. These results in poor accuracy of the double compression detection for color JPEG images with the same quantization matrix. To solve this problem, we propose an effective method that utilizes third-order polynomial fitting for error convergence curves. Firstly, five successive compressions are used to extract the quantization error, dequantization error, coefficient error, and truncation error in each compression and decompression process. Secondly, based on the convergence characteristics of these four types of error information, a third-order polynomial model and least squares are applied for the fit, and then, the slope of each point of the fitted curve and the difference of the slopes are used as convergence characteristics. Moreover, the fitted curves predict the pre-compression state, which can effectively amplify the gap between single and double compression. Finally, support vector machines (SVM) are used to train and predict the final features. The experiments illustrate that the proposed method enhances accuracy by 2–3% compared to the most recent method and by approximately 15% compared to the earlier method in multiple datasets, including NRCS, MIXDATA, and MIXDATA-I. [ABSTRACT FROM AUTHOR]

With the rapid increasing mileage of China's long-distance oil and gas pipelines, the intersection construction with other civil engineering, encroachment by invading the pipeline route, and other third-part problems occurred occasionally. Heavy vehicles rolling the serving pipeline have become one of the inevitable safety risks. The field test method of three in-service long oil and gas pipelines under heavy vehicle rolling is elaborated. The pipeline stress and soil pressure during tests are monitored and analyzed. The parametric model of pipe mechanical response under heavy vehicle rolling and stacking load is established, and the quantitative feedback of each parameter on pipeline stress safety response under heavy vehicle rolling is formed. The results show that the influence factors such as vehicle weight, vehicle speed, buried depth of pipeline, horizontal distance and cover plate on the stress state, vertical displacement state, and contact stress of pipe soil interface are highly consistent with the finite element method and test method, which could be a guideline for the safety assessment at rolling site. [ABSTRACT FROM AUTHOR]

Detecting double JPEG compression with the same quantization matrix is a challenging task in image forensics. To address this problem, in this paper, a novel method is proposed by leveraging the component convergence during repeated JPEG compressions. Firstly, an in-depth analysis of the pipeline in successive JPEG compressions is conducted, and it reveals that the rounding/truncation errors as well as JPEG coefficients tend to converge after multiple recompressions. Based on this fact, the backward quantization error (BQE) is defined, and we find that the ratio of non-zero BQE for single compression is larger than that for double compression. Moreover, to exploit the convergence property of JPEG coefficients, a multi-threshold strategy is designed for capturing the statistics of the number of different JPEG coefficients between two sequential compressions. Finally, the statistical features of the dual components are concatenated into a 15-D vector to detect double JPEG compression. Experimental results demonstrate the efficiency of the proposed method, which outperforms some state-of-the-art schemes. [ABSTRACT FROM AUTHOR]

Detection of inconsistencies of double JPEG artifacts across different image regions is often used to detect local image manipulations, like image splicing, and to localize them. In this paper, we move one step further, proposing an end-to-end system that, in addition to detecting and localizing spliced regions, can also distinguish regions coming from different donor images. We assume that both the spliced regions and the background image have undergone a double JPEG compression, and use a local estimate of the primary quantization matrix to distinguish between spliced regions taken from different sources. To do so, we cluster the image blocks according to the estimated primary quantization matrix and refine the result by means of morphological reconstruction. The proposed method can work in a wide variety of settings including aligned and non-aligned double JPEG compression, and regardless of whether the second compression is stronger or weaker than the first one. We validated the proposed approach by means of extensive experiments showing its superior performance with respect to baseline methods working in similar conditions. [ABSTRACT FROM AUTHOR]

Coenzyme Q10 (CoQ10) has a wide range of physiological functions and therapeutic value. However, its biomedical application as a health product or drug is limited by its insolubility and low bioavailability. Single-walled carbon nanotubes (SWCNTs) have attracted great interest for drug or therapeutic agent delivery due to their unique properties. In this study, the pristine SWCNTs are purified with different oxidizing acid, and the resulting shortened CNTs (CNTs-COOH) are conjugated with poly-(ethylene glycol) (PEG) groups. Afterwards, CoQ10 is loaded by CNTs carriers. CNTs carriers are systematically characterized and evaluated in terms of drug loading, in vitro release, cytotoxicity, and cellular uptake. The results reveal that the sizes (length) of CNTs-COOH and CNTs-PEG are 253.2 and 328.7 nm, respectively, and they have high loading capacity for CoQ10 and low cytotoxicity toward Caco-2 cells. In comparison with CNTs-COOH, CNTs-PEG exhibited better sustained-release property for CoQ10. Also, CNTs-PEG carriers loaded with CoQ10 can be effectively delivered into cells and have enhanced cellular uptake efficiency over time. Further study results of the uptake mechanism illustrate that CNTs-PEG can be internalized into cells through the broader and more efficient entry routes, including direct penetration, clathrin-mediated endocytosis and macropinocytosis pathway. In summary, the PEG-conjugated CNTs may be used as novel nanocarriers, and the findings will contribute to the rational design of multifunctional delivery vehicles for CoQ10. [ABSTRACT FROM AUTHOR]

Available model-based techniques for the estimation of the primary quantization matrix in double-compressed JPEG images work only under specific conditions regarding the relationship between the first and second compression quality factors, and the alignment of the first and second JPEG compression grids. In this paper, we propose a single CNN-based estimation technique that can work under a wide range of settings. We do so, by adapting a dense CNN network to the problem at hand. Particular attention is paid to the choice of the loss function. Experimental results highlight several advantages of the new method, including: i) capability of working under very general conditions, ii) improved performance in terms of MSE and Accuracy, especially in the non-aligned case, iii) better spatial resolution due to the ability of providing good results also on small image patches. [ABSTRACT FROM AUTHOR]

CoSaMP is a kind of effective reconstruction algorithm of compressed sensing. The principle of selecting and removing atoms is different in each interation leads to the estimation of the support set is inaccurate. This paper proposed a compressed sampling hard threshold reconstruction algorithm. It had the advantage of both algorithms and incorporated HTP in removing atoms to make the consistent principle. Its theoretically made certain of selecting atoms more accurate in each iteration. Experimental results demonstrate that the algorithm in terms of accuracy of the reconstruction is superior to the above two algorithms, compared with the other algorithms, it has the feature of high reconstruction accuracy, noise immunity and stablity. [ABSTRACT FROM AUTHOR]