Copy-Move forgery detection based on Harris Corner points and BRISK

The copy-move forgery is a common way to manipulate the digital images, which copied regions come from the same image. The detection process of altered regions is known as forgery detection. In this paper, we propose a new block-based approach for detecting copy-move forgery in digital images. The novelty of the proposed approach is the usage of structural similarity index as the method for similarity matching step. Additionally, Gaussian pyramid decomposition method allows us to improve run-time speed of the approach considerably. Therefore, feature extraction would not require, hence; it can help to diminish time-consuming issue. Accordingly, simplicity in calculating and analyzing is the significant specification of the proposed approach. Experiments are provided to illustrate an efficiency of suggested approach and evaluate its robustness and sensitivity against some post-processing operations.

One of the most popular image forgery technique is copy-move forgery. In this technique, one or more segments are copied and affixed at different positions within the image. This forgery technique is highly grievous as it can manipulate an image in various ways (such as by presenting additional information or by concealing the genuine information of image). We propose a novel blind forensic technique for copy-move image forgery detection. Our approach utilize different edge detection operators to extract high frequency features. Histogram of Oriented Gradients (HOG) and Weber Local Descriptor (WLD) are used to extract image block features. Radix and lexicographical sorting is enforced over feature vector matrix followed by correlation computation between feature vectors to detect similar feature vectors. Shift vectors are computed to locate similar group of blocks within image. Connected component labeling is applied as morphological operation to remove false matches. Proposed approach is robust to detect plain as well as multiple copy-move forgery in images with post-processing attacks such as contrast adjustment, image blurring, color reduction, and brightness change. Proposed approach achieve highest F-Measure(%) in comparision to other existing forgery detection methods.

Abstract. In this article the new method for iris image features extraction based on phase congruency is proposed. Iris image key points are calculated using the convolutions with Hermite transform functions. At each key point the feature vector characterizing this key point is obtained based on the phase congruency method. Iris key point descriptor contains phase congruency values at points located on concentric circles around the key point. To compare the key points, Euclidean metric between the key points descriptors is calculated. The distance between the iris images is equal to the number of matched iris key points. The proposed method was tested using the images from CASIA−IrisV4−Interval database and the value of EER = 0.226% was obtained.

Copy---move image forgery detection has recently become a very active research topic in blind image forensics. In copy---move image forgery, a region from some image location is copied and pasted to a different location of the same image. Typically, post-processing is applied to better hide the forgery. Using keypoint-based features, such as SIFT features, for detecting copy---move image forgeries has produced promising results. The main idea is detecting duplicated regions in an image by exploiting the similarity between keypoint-based features in these regions. In this paper, we have adopted keypoint-based features for copy---move image forgery detection; however, our emphasis is on accurate and robust localization of duplicated regions. In this context, we are interested in estimating the transformation (e.g., affine) between the copied and pasted regions more accurately as well as extracting these regions as robustly by reducing the number of false positives and negatives. To address these issues, we propose using a more powerful set of keypoint-based features, called MIFT, which shares the properties of SIFT features but also are invariant to mirror reflection transformations. Moreover, we propose refining the affine transformation using an iterative scheme which improves the estimation of the affine transformation parameters by incrementally finding additional keypoint matches. To reduce false positives and negatives when extracting the copied and pasted regions, we propose using "dense" MIFT features, instead of standard pixel correlation, along with hysteresis thresholding and morphological operations. The proposed approach has been evaluated and compared with competitive approaches through a comprehensive set of experiments using a large dataset of real images (i.e., CASIA v2.0). Our results indicate that our method can detect duplicated regions in copy---move image forgery with higher accuracy, especially when the size of the duplicated region is small.

In this paper we introduce a new dataset and pose invariant sampling method and describe the ensemble methods used for recognizing faces in 3D scenes, captured using commodity depth sensors. We use the 3D SIFT key point detector to take advantage of the similarities between faces, which leads to a set of points of interest based on the curvature of the face. For all key points, features are extracted using a 3D feature descriptor. Then, a variable-sized amount of features are generated per each 3D face image. The first ensemble method we constructed uses a K-nearest neighbors classifier to classify each key point-sampled feature vector as belonging to one of the subjects recorded in our dataset. All votes over all key points are combined. In the second ensemble technique, the key points are clustered with K-means, using the feature vectors and approximated sampling positions relative to the face. This leads to a set of experts that specialize for a specific region. Then a K-nearest neighbors classifier is trained on the examples falling in each expert's specialized region. Finally, for a new 3D face image, votes from all experts are combined in a sum ensemble technique to categorize the 3D face. We also introduce 6 new real world datasets with different variances: 3 types of 3D rotations, distance to sensor, expressions, and an all-in-one dataset. The results show very high cross validation accuracies for the same type of variance. In addition, 36 variance specific pair-tests in which the system is trained on one dataset and tested on a completely different dataset also show encouraging results.

This paper presents a robust rotation, scaling and translation (RST) invariant image watermarking method based on locally detected features. First, the feature points are detected in the original image by using the Harris corner detection. Then, the Delaunay tessellation is created on these feature points. Watermark data are embedded and detected in each of the Delaunay triangles. The Harris corner detection is the key point in this scheme. Traditionally, the global threshold is used for the Harris corner detection. As a result, the points are concentrated on areas with rich texture information and the contrast change within the image. In this way, the locations of points are seriously affected by attacks, such as, geometrical attacks. It makes the watermark detection difficult or even impossible. In order to generate more robust feature points, we use a local threshold feature detection method, in which local thresholds are used for different parts of the target image. The feature points are almost uniformly distributed on the image. The experimental results show that this method makes feature points very robust after geometrical attacks, JPEG compression and noise addition.

Due to the availability of media editing software, the authenticity and reliability of digital images are important. Region manipulation is a simple and effective method for digital image forgeries. Hence, the potential to identify the image manipulation is current research issue these days and copy–move forgery detection (CMFD) is a main domain in image authentication. In copy–move forgery, one region is simply copied and pasted over other region in the same image for manipulating the image. In this paper, we have proposed a method based on Harris corner and adaptive non-maximal Suppression (ANMS). Initially, the input image is taken, and then Harris corner detection algorithm is used to detect the interest points, and ANMS is adopted to control the number of Harris points in an image. This gives an appropriate number of interest points for different size of images and gives the assurance for finding the manipulated region in manageable time. For each extracted interest point, SIFT is used for calculating the descriptors. Now obtained descriptors are matched using the outlier rejection with nearest neighbour. Here RANSAC is used to find the best set of matches to identify the manipulated regions. Experimental results show the robustness against different transformation and post-processing operations.

Objective To explore the effects of assessment system based on key points in clinical skills training among nursing interns. Methods Nursing interns of the Affiliated Cancer Hospital of Zhengzhou University were selected as study subjects from January to December 2016 by the method of convenience sampling. They were divided into experimental group (n=50, practice started from January 2016) and control group (n=50, practice started from June 2016) according to the order of internship. Students in control group adopted the conventional skill training and assessment, while students in experimental group received the assessment system based on key points. Critical thinking skills of nursing interns of both groups were compared with the critical thinking disposition inventory (CTDI) . Results After training, the total score of CTDI of students (299.82±26.95) in experimental group was higher than that (283.41±24.24) in control group with a significant difference (t=3.201, P=0.002) . The scores of 7 dimensions in CTDI were (41.18±4.12) , (40.27±3.16) , (46.10±2.00) , (40.11±5.31) , (42.97±5.05) , (43.96±3.88) , (45.23±3.08) significantly higher than those in control group[ (39.62±3.09) , (38.62±4.15) , (42.04±2.95) , (37.92±3.65) , (39.50±3.57) , (41.82±5.17) , (43.51±2.64) ] (t=2.142, 2.237, 8.074, 2.402, 3.967, 2.341, 2.981; P<0.05) . Conclusions The assessment system based on key points can effectively improve the critical thinking skills of nursing interns. It is worth to be used widely. Key words: Nursing care; Intern; Key point; Clinical skill; Critical thinking

Due to the availability of various image processing tools forgery over an image can be performed very easily but very difficult to identify. In copy-move forgery, a segment is copied from the original image and pasted at some other location on the same image to hide significant objects of image or to bring additional information which is originally not present in image. Nowadays, this forgery technique is drawing attention. Till now many solutions are presented by researchers to detect such type of forgery in images. Several post-processing operations like rotation, alteration in intensity, noise addition, filtering and blurring can be applied over copy-moved segment which makes detection of forgery very difficult. Copy-move forgery detection is mainly based on finding similarity present in an image and establish a relationship between genuine image parts and pasted portion of the image. This paper is centralized towards providing survey to forgery detection techniques based on different block-based methods. In block-based methods image is divided in blocks of fixed dimension and further features are extracted corresponding to each block of image. Forged blocks are identified utilizing the similarity present between feature vectors.

On Image Forgery Detection Using Two Dimensional Discrete Cosine Transform and Statistical Moments

Images are one of the most prominently used digital information sharing medium now a days. Due to availability of state-of-the-art image editing tools it has become very easy to forge an image. Among various types of image forgeries, copy-move (region-duplication) forgery cases are emerging very frequently. In copy-move image forgery one or more regions of an image are replicated within the same image. In this paper, a new robust copy-move image forgery detection technique is proposed using Gaussian-Hermite Moments (GHM). The proposed technique divides the input image into overlapping blocks of fixed size and then the Gaussian-Hermite moments are extracted for each block. The matching of similar blocks is done by sorting all the features lexicographically. The experimental results show that the proposed technique can locate the copy-move forged regions in a forged image very accurately. The proposed technique shows promising results in the presence of various post-processing operations scaling, blurring, color reduction, adjustment of brightness, rotation, and JPEG compression.

With the rise of computer vision, it is becoming more and more important to accurately recognize and evaluate human actions. However, the complexity, intraclass differences, and viewing angle changes of human actions significantly impact the accuracy of identification human actions. This paper proposed an action recognition and evaluation method based on skeleton information extraction. Briefly, We use Lightweight OpenPose to extract the key points of human skeleton and perform processing work, including video data cutting, deleting some key points, supplementing missing key points, filtering processing, feature extraction, etc. Through an in-depth exploration of related theoretical technologies, we proposed a model for recognition and evaluation of human table tennis actions with an ordinary camera. The support vector machine algorithm (SVM) classification model is used to identify table tennis actions in real-time. Then the dynamic time regularization (DTW) algorithm calculates the similarity of each human skeleton key point in the action sequence. The low-scoring bone key points are marked to evaluate the human table tennis action in real time. The results show that a recognition rate of more than 95% is achieved in the test set, which proves the method's effectiveness. In addition, we compared the results with previous work using inertial sensors for action recognition, which shows our method can preserve the same accuracy with a much lower cost of implementation.

BackgroundDrosophila melanogaster is an important organism used in many fields of biological research such as genetics and developmental biology. Drosophila wings have been widely used to study the genetics of development, morphometrics and evolution. Therefore there is much interest in quantifying wing structures of Drosophila. Advancement in technology has increased the ease in which images of Drosophila can be acquired. However such studies have been limited by the slow and tedious process of acquiring phenotypic data.ResultsWe have developed a system that automatically detects and measures key points and vein segments on a Drosophila wing. Key points are detected by performing image transformations and template matching on Drosophila wing images while vein segments are detected using an Active Contour algorithm.The accuracy of our key point detection was compared against key point annotations of users. We also performed key point detection using different training data sets of Drosophila wing images. We compared our software with an existing automated image analysis system for Drosophila wings and showed that our system performs better than the state of the art. Vein segments were manually measured and compared against the measurements obtained from our system.ConclusionOur system was able to detect specific key points and vein segments from Drosophila wing images with high accuracy.

Biharmonic deformation transfer with automatic key point selection

Abstract. Remote sensing techniques are an important tool in fluvial transport monitoring, since they allow for effective evaluation of the volume of transported material. Nevertheless, there is no methodology for automatic calculation of movement parameters of individual rocks. These parameters can be determined by point cloud registration. Hence, the goal of this study is to develop a robust algorithm for terrestrial laser scanning point cloud registration. The registration is based on Iterative Closest Point algorithm, which requires well established initial parameters of transformation. Thus, we propose to calculate the initial parameters based on key points representing the maximum of Gaussian curvature. For each key point the set of geometrical features is calculated. The key points are then matched between two point clouds as a nearest neighbor in feature domain. Different combinations of neighborhood sizes, feature subsets, metrics and number of nearest neighbors were tested to obtain the highest ratio between properly and improperly matched key points. Finally, RANSAC algorithm was used to calculate the initial transformation parameters between the point clouds and the ICP algorithm was used for calculation of final transformation parameters. The investigations carried out on sample point clouds representing rocks enabled the adjustment of parameters of the algorithm and showed that the Gaussian curvature can be used as a 3-dimentional key point detector for such objects. The proposed algorithm enabled to register point clouds with the mean distance between point clouds equal to 3 mm.