Contour Position Research Articles

A sweeping optimization algorithm for the global cosine fitting energy image segmentation model

AbstractImage segmentation plays a pivotal role in image processing. Level set model is a traditional variation image segmentation method. In order to achieve level set evolution equation, the level set energy functionals are minimized with the gradient descent methods and then the partial differential equation (PDE) was solved by finite difference scheme. Slow speed is one of its disadvantages. We propose a sweep optimization algorithm based on global cosine fitting (GCF) energy. Instead of calculating the PDE and the curvature, the proposed sweeping algorithm directly calculates the energy change when a pixel moves from one side of evolving contour to the other. It checks whether the GCF energy is decreased or not. The proposed algorithm has many advantages. For example, independent of initial level set contour positions and parameters, need not consider the Courant Friedrichs Lew condition and the regularization energy term. The proposed algorithm can be easily extended to high dimension image segmentation. The experiments on synthetic images, noise images and real images demonstrate the effectiveness of the proposed sweeping optimization algorithm.

Grape Berry Detection and Size Measurement Based on Edge Image Processing and Geometric Morphology

Counting grape berries and measuring their size can provide accurate data for robot picking behavior decision-making, yield estimation, and quality evaluation. When grapes are picked, there is a strong uncertainty in the external environment and the shape of the grapes. Counting grape berries and measuring berry size are challenging tasks. Computer vision has made a huge breakthrough in this field. Although the detection method of grape berries based on 3D point cloud information relies on scanning equipment to estimate the number and yield of grape berries, the detection method is difficult to generalize. Grape berry detection based on 2D images is an effective method to solve this problem. However, it is difficult for traditional algorithms to accurately measure the berry size and other parameters, and there is still the problem of the low robustness of berry counting. In response to the above problems, we propose a grape berry detection method based on edge image processing and geometric morphology. The edge contour search and the corner detection algorithm are introduced to detect the concave point position of the berry edge contour extracted by the Canny algorithm to obtain the best contour segment. To correctly obtain the edge contour information of each berry and reduce the error grouping of contour segments, this paper proposes an algorithm for combining contour segments based on clustering search strategy and rotation direction determination, which realizes the correct reorganization of the segmented contour segments, to achieve an accurate calculation of the number of berries and an accurate measurement of their size. The experimental results prove that our proposed method has an average accuracy of 87.76% for the detection of the concave points of the edge contours of different types of grapes, which can achieve a good edge contour segmentation. The average accuracy of the detection of the number of grapes berries in this paper is 91.42%, which is 4.75% higher than that of the Hough transform. The average error between the measured berry size and the actual berry size is 2.30 mm, and the maximum error is 5.62 mm, which is within a reasonable range. The results prove that the method proposed in this paper is robust enough to detect different types of grape berries.

Preparation and performance of the ultra-high performance mortar based on simplex-centroid design method

The mix proportion, phase diagram components and mechanical properties of ultra-high performance mortar (UHPM) based on simplex-centroid design method were investigated. The effects of material components, sand/binder ratio (S/B) and water/binder ratio (W/B) on the strength and fluidity of UHPM were studied. Simultaneously, the relationship between water reducer dosage and slump flow of UHPM was investigated as well as the mix proportion design and performance prediction. The results showed that the simplex-centroid design method can be used to determine the relationship between influence factors and performance of UHPM. The differences of strength phase diagram for different mix proportion of UHPM were manifested in central position of minimum strength, strength contours and gradient, and position of maximum strength. There has a quadratic function relationship between water reducer dosage, slump flow and W/B. The slump flow of UHPM increases with the increase of water reducer dosage. The UHPM can be prepared based on simplex-centroid experimental design method.

Methods and procedure of referenced in situ control of lateral contour displacements in additive manufacturing

Abstract. Additive manufacturing technologies are further developing from prototype to serial production. This trend requires rising challenges to the process-accompanying quality assurance. Optical in situ quality control approaches show great potential to generate accurate measurement data, which are essential for feedback control. If a reliable referencing concept for the layer-by-layer measured data is guaranteed, contour information can be used during the manufacturing to correct occurring geometrical deviations. Within this scientific study, two methods of optical, referenced in situ control of lateral displacements of additive manufactured contours are presented. In the first approach the 2-D contour of the melting pool is analysed in relation to a position-stable reference system implemented in the powder bed. The second approach uses the translucent contour of deeper layers covered with powder as a reference. Within the image evaluation several pre-processing steps like calibration, undistortion, rectification, illumination correction and low-pass filtering are essential for reliable and correct geometric measurements. The following adapted contour detection and position determination of the referenced melting pool contours are based on an extended edge detection algorithm according to Canny (1986). With the evaluation of further manufacturing layers of already lowered powder bed levels, it is possible to specify the influence of powder application on geometrical displacements separately. This is done by a comparison of the position of the detected powder-covered melting pool contours with the previously applied melted region. Consequently a better understanding of lateral contour displacements within the additive manufacturing process is the goal, which is important for a process-accompanying correction of geometrical deviations.

Cleft Lip/Nasal Deformities After Plastic Surgery for Unilateral Cleft Lip/Palate: A Prospective Study at a Large Hospital in Vietnam.

IntroductionCongenital cleft lip, with or without cleft palate, is the most common deformity of the face. Primary plastic surgery for rehabilitation and esthetics is important for patients and their parents; however, secondary deformities of the lip and nose can occur after the primary surgery. Therefore, we performed assessment of secondary cleft lip/nasal deformities to aid in planning of surgical repair of these deformities.Materials and MethodsForty-six patients with unilateral cleft lip, with or without cleft palate, were operated with different techniques and examined post-surgery at the Department of Maxillofacial Surgery, University of Medicine and Pharmacy Hospital and Center of Odonto-Stomatology, Hue Central Hospital. They were assessed according to Motier’s post-operative evaluation scale (1997), including the red lip, white lip, scars, and nose.ResultsV notch and defect on the shift line were the most common deformities on the red lip (52.2%). About 34.8% of the patients had a short white lip on the cleft side. Straight and prominent scars were observed in 52.2% of the patients. The most common deformities of the nose were septal deviation (78.3%), followed by defects in the upper part of the nostril contour (78.3%), narrow sill (52.2%), and low position of the ala (47.8%).ConclusionSecondary cleft lip/nasal deformities are unavoidable. It is necessary to develop a plan for surgical repair of these deformities. There is no single method of cleft lip surgery that gives perfect results. Therefore, clinicians choose a combination of methods to bring optimal results for each patient.

A hybrid level set model for image segmentation.

Active contour models driven by local binary fitting energy can segment images with inhomogeneous intensity, while being prone to falling into a local minima. However, the segmentation result largely depends on the location of the initial contour. We propose an active contour model with global and local image information. The local information of the model is obtained by bilateral filters, which can also enhance the edge information while smoothing the image. The local fitting centers are calculated before the contour evolution, which can alleviate the iterative process and achieve fast image segmentation. The global information of the model is obtained by simplifying the C-V model, which can assist contour evolution, thereby increasing accuracy. Experimental results show that our algorithm is insensitive to the initial contour position, and has higher precision and speed.

Light-driven Lifshitz transitions in non-Hermitian multi-Weyl semimetals

Non-Hermitian topological systems are the newest additions to the growing field of topological matter. In this work, we report the light-driven exceptional physics in a multi-Weyl semimetal. The driving is not only a key ingredient to control the position of the exceptional contours (ECs); light also has the ability to generate new ECs. Interestingly, we also demonstrate topological charge distribution and Lifshitz transition, which are controllable by the driving field in such generated ECs. Our findings present a promising platform for the manipulation and control over exceptional physics in non-Hermitian topological matter.

REDUCTION MAMMOPLASTY FOR BENIGN PHYLLODES TUMOUR IN AN ADOLESCENT FEMALE

Phyllodes tumours are rare neoplasm of female breast especially among adolescent women. We present a case of 17 year old female patient present with large benign phyllodes tumour. The patient was treated with one stage excision with reduction mammoplasty. Symmetry of the breast contour and nipple areola complex position could be restored. Standard plastic surgery techniques like reduction mammoplasty might be applied in treating large benign tumours not compromising the aesthetic aspect of the breast.

Objective evaluation of orbito-zygomatic reconstruction with scapular tip free flaps to restore facial projection and orbital volume

BackgroundRestoring anatomical contour and position of the malar eminence and orbital rim following ablative mid-face procedures is critical in maintaining facial contour and orbit position. ObjectiveTo report our reconstructive approach using the scapular tip free-flap (STFF) for orbito-zygomatic defects, evaluating contour and overall shape restoration. MethodsThe study included 2 series: a clinical cohort of 15 consecutive patients who underwent an orbito-zygomatic reconstruction with a STFF and a cohort of 10 patients who had CT scan imaging but did not have orbito-zygomatic surgical resection or reconstruction. Using a 3D software, overall conformance (OC) and contour conformance (CC) with respect to the mirrored contralateral (clinical cohort) or native zygoma (preclinical cohort) were analyzed. Postoperative orbital volumes were also measured in the clinical cohort. Mean, median, root-mean-square (RMS), minimum and maximum measurements were obtained both for OC and CC. Conformance values of clinical and preclinical cohort were compared to objectively evaluate the quality of reconstruction in terms of orbito-zygomatic framework restoration (Mann-Whitney test). ResultsAll measurements for OC and CC between scapular tip and the zygoma showed no differences, both on the clinical (RMS: OC 3.29 mm vs CC 3.32 mm -p = NS-) and preclinical (RMS: OC 2.03 mm and CC 2.31 mm -p = NS-) cohorts. Moreover, there were no differences in post-operative orbital volumes in the clinical cohort. Clinical outcomes of the case-series are also reported. ConclusionThe STFF is highly effective in restoring facial projection and orbital volume in orbito-zygomatic reconstruction.

Planning of ore shotpileselective mining by the geoinformation technologies in the condition of the Ferrexpo Eristovo Mining

Purpose. Develop method for predicting the displacement of ore contours in the shotpile after the explosion to planning the ore raw materials selective mining at the development of iron ore quarries. Research methodology. Actual surface measurements were used to determine the loosening coefficient for individual sections of rock mass collapse. The analytical methods were used to calculate the planes of the face sections before and after the explosion. Determination of the predicted position of the contours of iron ore in the shotpile was performed by the method of graphical selection. The results. It is established that the loosening coefficient of the rock is variable in individual parts of the ore block and can be used to determine the predicted position of the ore contour. The main difference of proposed predicting methods consist in establish the expected position of contact of rocks and geological markers in the field, which will allow in the regular mode to control the development of the face by a pit geologist. Scientific novelty. The dependence of the predicted position of the ore contour in the rock mass shotpile on the method of actual survey of the pit surface "before" and "after" the explosion when performing geometric constructions is established. Determined that the proposed method of prediction allow to minimize costs in the form of insignificant organizational changes at planning observance of qualitative indicators, reduction of risks and dangers at geological works is provided, and also efficiency of works on short-term planning system in rock mass shotpile increases. Practical value. A method for determining the position of the ore contour in the rock mass shotpile has been developed. The possibility of using the predicted position of the ore contour for planning the selective mining of ore shotpile has been established. The expected economic effect of the proposed solutions is achieved by reducing the cost on processing rocks and low-grade ore when they fall on the crusher due to erroneous classification during the selective development of ore deposits.

RMCA-LSA: A Method of Monkey Brain Extraction

The traditional level set algorithm selects the position of the initial contour randomly and lacks the processing of edge information. Therefore, it cannot accurately extract the edge of the brain tissue. In order to solve this problem, this paper proposes a level set algorithm that fuses partition and Canny function. Firstly, the idea of partition is fused, and the initial contour position is selected by combining the morphological information of each region, so that the initial contour contains more brain tissue regions, and the efficiency of brain tissue extraction is improved. Secondly, the canny operator is fused in the energy functional, which improves the accuracy of edge detection of rhesus monkey brain tissue while retaining the advantage of the traditional level set algorithm in processing an uneven gray image. Experimental results show that the algorithm can accurately extract the brain tissue of rhesus monkeys with an accuracy of up to 86%.

Detection and Tracking Cows by Computer Vision and Image Classification Methods

In this paper, the cow recognition and traction in video sequences is studied. In the recognition phase, this paper does some discussion and analysis which aim at different classification algorithms and feature extraction algorithms, and cow's detection is transformed into a binary classification problem. The detection method extracts cow's features using a method of multiple feature fusion. These features include edge characters which reflects the cow body contour, grey value, and spatial position relationship. In addition, the algorithm detects the cow body through the classifier which is trained by Gentle Adaboost algorithm. Experiments show that the method has good detection performance when the target has deformation or the contrast between target and background is low. Compared with the general target detection algorithm, this method reduces the miss rate and the detection precision is improved. Detection rate can reach 97.3%. In traction phase, the popular compressive tracking (CT) algorithm is proposed. The learning rate is changed through adaptively calculating the pap distance of image block. Moreover, the update for target model is stopped to avoid introducing error and noise when the classification response values are negative. The experiment results show that the improved tracking algorithm can effectively solve the target model update by mistaken when there are large covers or the attitude is changed frequently. For the detection and tracking of cow body, a detection and tracking framework for the image of cow is built and the detector is combined with the tracking framework. The algorithm test for some video sequences under the complex environment indicates the detection algorithm based on improved compressed perception shows good tracking effect in the changing and complicated background.

Supermoon Drives Beach Morphological Changes in the Swash Zone

AbstractThe effect of the supermoon, which appears much larger than a normal full moon, on the morphological changes of a sandy beach was investigated by analyzing a 25‐year daily observation data set of beach morphology in the swash zone. The beach morphology fluctuated in two cycles related to the supermoon: the semisynodic month cycle (from full moon to new moon, and vice versa) and the anomalistic month cycle (from perigee to perigee). The supermoon makes the erosion of the upper swash zone more likely by generating a larger tidal range. The high‐water‐level contour positions observed during supermoons retreated significantly, although there were no trends in the change for all the observations. Erosion due to high waves coincident with a supermoon can be expected to be more severe in the upper swash zone; including the supermoon effect in beach morphodynamic models can improve coastal management.

Estimation and Uncertainties of Profiles and Equilibria for Fusion Modeling Codes

The results of transport modeling codes, e.g., GENE for the plasma core or SOLPS-ITER for the plasma edge, depend critically on reliable profile and equilibrium estimates. The propagation of uncertainties (UP) of input quantities to the results of modeling codes, e.g., power and particle exhaust and plasma stability, is frequently neglected because of the costs of running the codes as well as because of the missing uncertainty quantification of input quantities. The situation becomes even more cumbersome if profile gradients and their uncertainties are of major concern for transport analyses. Two different techniques are presented to estimate profiles, profile gradients, their uncertainties, and candidate profiles for UP in modeling codes. Markov Chain Monte Carlo sampling of the posterior probability density of an integrated data analysis approach is applied to estimate electron density and temperature profiles. Nonstationary Gaussian process regression is applied to estimate ion temperature and angular velocity profiles. Both methods provide in a natural way profile gradients, profile logarithmic gradients, and their uncertainties. Modeling codes benefit also from reliable equilibrium reconstructions and quantification of the uncertainty of various equilibrium parameters. For the analysis of diagnostics data, the position and uncertainty of flux surfaces as well as of the magnetic axis are important. For plasma transport and stability codes, the estimation of uncertainties of current and q-profiles is presented. For plasma edge codes the position of the separatrix contour and its uncertainty at various poloidal positions is of primary interest especially if steep profile gradients are present. Examples of uncertainties and their sources in magnetic scalar quantities, profiles, and separatrix contours are shown.

Active contours driven by modified LoG energy term and optimised penalty term for image segmentation

An active contour model to segment the images is proposed by combining local binary fitting (LBF) energy function and modified Laplacian of Gaussian (MLoG) energy function. A MLoG energy function based on a new boundary indicator function or edge stop function (ESF) is introduced to smoothen the homogeneous regions and enhance the edge information of objects. Also, MLoG energy term with LBF energy term is incorporated to drive the initial contour towards the object boundary. Finally, the penalty term is replaced with a new optimized potential function, which can improve the corresponding speed function. By adding the optimized area energy term, contour position is accelerated towards the object boundary. Further, the addition of MLoG based on new ESF, makes the proposed model insensitive to the initial contour. Experiments are performed on various real images, MS-COCO 2014 train data set images and Segmentation Evaluation Database images shared in Weizmann Institute of Science website. The proposed model provides better segmentation results compared to the other state of the art models in terms of segmentation accuracy, F-score and CPU execution time. Further, experimental results also prove the robustness of the proposed model in terms of contour initialization, intensity inhomogeneity and noise.

A Novel Global Energy and Local Energy-Based Legendre Polynomial Approximation for Image Segmentation

Active contour model (ACM) is a powerful segmentation method based on differential equation. This paper proposes a novel adaptive ACM to segment those intensity inhomogeneity images. Firstly, a novel signed pressure force function is presented with Legendre polynomials to control curve contraction. Legendre polynomials can approximate regional intensities corresponding to evolving curve. Secondly, global term of our model characterizes difference of Legendre coefficients, and local energy term characterizes fitting evolution curve of interested region. Final contour evolution will minimize the energy function. Thirdly, a correction term is employed to improve the performance of curve evolution according to the initial contour position, so wherever the initial contour being in the image, the object boundaries can be detected. Fourthly, our model combines the advantages of two classical models such as good topological changes and computational simplicity. The new model can classify regions with similar intensity values. Compared with traditional models, experimental results show effectiveness and efficiently of the new model.

The Impact and Importance of Fabric Image Preprocessing for the New Method of Individual Inter-Thread Pores Detection

Abstract The paper describes the impact and importance of preprocessing methods of fabric image for detection of inter-thread pores (ITP), which is a new method of individual ITP identification. The aim of this experiment is to identify precisely every individual ITP of fabric structure by using optimal preprocessing algorithm for further quantitative, morphometric structural analysis of specialized fabrics (barriers, industrial filters, composites, others) in context of air permeability, flow resistance, UV radiation, viruses penetration, thermal comfort by estimation fabric porosity, especially macroporosity parameters and cover factor. The correct identification of individual ITP depends on the acquisition method and the preprocessing algorithm. It was conducted by analyzing the adaptation of digital image preprocessing methods for two structures of plain weave fabric in two magnification zooms, 1.25 and 0.8. Preprocessing operations were performed in the area of spatial operations of the image. The optimal preprocessing algorithm includes low-pass filtering, histogram equalization, nonlinear filtering, thresholding, and morphological operation. This algorithm was selected based on the factors developed by the author (ITP detection, RID factor—a difference between the real and model ITP areas) which rely on the ITP size, shape, and location. The graphic view of the ITP contour position on the fabric image is a verification element in the optimal preprocessing algorithm. The presented results of the air permeability of two different plain weave structures confirm the need to optimize the algorithm of pre-image processing methods to precisely detect each individual ITP in the fabric image.

A novel curvature circle iterative algorithm for contour error control of multi-axis CNC machine tools

High-precision real-time estimation of contouring errors is a prerequisite for contouring errors control of multi-axis CNC machine tools. This paper focuses on developing a nearest point projection curvature circle iterative (NPP–CCI) algorithm to achieve real-time estimation of multi-axis contouring errors. It is found that the traditional curvature circle iterative (CCI) method has two major shortcomings. The first is that the iterative process may terminate incorrectly at the local contour position, and the other is that the actual tool position and local curvature circle are not necessarily coplanar in three-dimensional space, which would lead to inaccurate calculation of the delay time parameter and eventually affect the estimation accuracy. In order to address the problem of false termination, an index method is used to find the closest reference position with respect to the actual position. At the same time, the projection technology is proposed to overcome the problem met in extending the planar curvature circle iterative method to the spatial applications. The proposed NPP-CCI algorithm is more suitable for spatial contouring errors estimation in tracking complex trajectories and has higher estimation accuracy than the traditional CCI algorithm. Various experiments with different tool paths are conducted on an in-house developed multi-axis experimental platform to verify the effectiveness of the proposed algorithm. The experimental results show that the NPP-CCI algorithm can estimate the contouring errors with higher accuracy than the traditional CCI algorithm, and with the help of real-time computation and compensation, the contouring errors are reduced by more than 44% in terms of the MAX and RMS values.

Heat diffusion embedded level set evolution for infrared image segmentation

In this study, the authors present a novel level set method for infrared image segmentation. Local region-based models can fit intensity inhomogeneity partly but they are sensitive to local window scale. To deal with it, they embed an heat diffusion process in conventional level set evolution and convert heat to a part of data term in level set energy function. Besides, bias field model can extract the local intensity clustering property of the image. Therefore, the proposed method can deal with the interference of intensity inhomogeneity and complex background if appropriate seeded pixels are selected. Finally, the energy functional is minimised by a combinatorial optimal algorithm in a graph model to get a global optimal solution and accelerate the level set evolution implementation. The experiments show that the proposed method is robust to parameter setting, noise, and initial contour position. The comparisons on a large quantity of infrared image datasets with standard level set methods also demonstrate the efficiency of the proposed method.

Comparative Study between Reconstruction of Grade III Gynecomastia in Single Stage versus Two Stage Reconstruction

Background: The difficulty of treating severe grades ofgynecomastia lies in the resection of excess skin. This resectioncan result in extensive scars located in conspicuous sites. Toreach the optimum results, excess skin should be excised andthe excess fat and gland should be managed too. Managingthe excess fat, enlarged mammary gland, together with excisionof excess periareolar skin with nipple-areola transposition insingle-stage is associated with higher risk of injuring thevascular pedicle of nipple-areola, and also associated withexcessive pleating of periareolar skin due to the suddenreduction in the size of areola which don't allow for skinretraction to occur. Staged-reconstruction will allow for gradualreduction in the size of areola allowing for skin adaptationleading to minimal pleating of periareolar skin, and alsopreserve the nipple-areola vascularity.Aim of Work: Is to compare between reconstruction ofgrade III gynecomastia in single-stage versus two-stage, asregard the complications rate.Patients and Methods: Twelve patients with severe (gradeIII) gynecomastia with enlarged ptotic nipple-areola, underwentsurgery over a 2-year period. All patients were marked preoperatively.Under general-anesthesia, traditional liposuctionof the pei-glandular area was performed, followed by deepithelializationof excess peri-areolar skin to elevate thenipple-areola. The glandular tissue was delivered by “pullthrough”technique, through a lateral trans-dermal peri-areolarincision. Study performed on two groups, group I, surgerywas performed in single-stage, while in group II, surgery wasperformed in two-stages, with liposuction of excess fat andresection of excess peri-areolar skin with elevation of nippleareolain the first stage then, three months later, patientsunderwent minimal liposuction just to facilitate delivery ofthe gland, with its delivery using the “pull-through” technique.Results: Fellow-up period was 6 months. No hematoma,seroma, breast skin necrosis, breast asymmetry, or nippleareolamalposition were detected post-operative in both groups.Results were reported as “uniformly good to excellent” on apatient satisfaction scale, as all patients were satisfied withtheir breasts contour and nipple-areola position postoperative.Transient hyposthesia of nipple-areola occurred and improvedspontaneously at 6 months post-operative. By comparing thecomplications rate between both groups, results showed thatsingle-stage reconstruction in group I was associated withhigher complications rate as regard the nipple-areola vascularity,and as regard the presence of excessive pleating of69periareolar skin than in group II. One case in group I showcomplete loss of nipple-areola. Another case of nipple-areolavascular compromise and partial necrosis were also detectedin group I. While, no cases showed compromised vascularityof nipple-areola in group II patients with two-stage reconstruction.Conclusions: Two-stage reconstruction is considered assafe procedure for correction of severe (grade III) gynecomastia,which preserve nipple-areola vascularity, and permitsbroad resection of excess skin and mammary tissue, whileavoiding unattractive scars on the patient's chest, with minimalpleating of periareolar skin.