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738 result(s) for "angle of extraction"
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Design and Experimental Study of an Extraction Force Measurement System for Densely Planted Cotton Stalks
The study of cotton stalk extraction resistance provides important parameters for the design of cotton stalk harvesting machinery. To investigate the effects of soil moisture content, cotton stalk diameter, and extraction angle on the extraction force of densely planted cotton stalks, this paper designs a real-time measurement system based on virtual instrument technology and conducts field tests. The tests were carried out in cotton fields at the First Farm in Aral City, Xinjiang, using the cotton variety “Xiulu Zhong 70”. Single-factor experiments were conducted with extraction angle and stalk diameter as influencing factors. A combined three-factor experiment was performed under the following conditions: soil moisture contents of 21.87% and 26.32%; extraction angles of 25°, 30°, and 35°; and cotton stalk diameters of 8.50–9.00 mm, 10.00–10.50 mm, and 11.50–12.00 mm. The results show that the minimum extraction force is required when the extraction angle is 30°. Soil moisture content significantly affects the extraction force, which increases with stalk diameter. The combined test results indicate that the order of significance of the three factors is as follows: cotton stalk diameter (A), extraction angle (B), and soil moisture content (C). The optimal combination is A1B1C2, corresponding to a diameter of 8.50–9.00 mm, an extraction angle of 35°, and a soil moisture content of 26.32%. Based on comprehensive analysis, the recommended extraction angle range is 30–35°. The proposed system can efficiently complete cotton stalk extraction force tests, and the collected data provide valuable references for the design of cotton stalk harvesting machinery. By appropriately selecting the extraction angle and conducting harvesting under suitable soil moisture conditions, it is possible to reduce power consumption and improve production efficiency.
Single-Stage Pose Estimation and Joint Angle Extraction Method for Moving Human Body
Detecting posture changes of athletes in sports is an important task in teaching and training competitions, but its detection remains challenging due to the diversity and complexity of sports postures. This paper introduces a single-stage pose estimation algorithm named yolov8-sp. This algorithm enhances the original yolov8 architecture by incorporating the concept of multi-dimensional feature fusion and the attention mechanism for automatically capturing feature importance. Furthermore, in this paper, angle extraction is conducted for three crucial motion joints in the motion scene, with polynomial corrections applied across successive frames. In comparison with the baseline yolov8, the improved model significantly outperforms it in AP50 (average precision) aspects. Specifically, the model’s performance improves from 84.5 AP to 87.1 AP, and the performance of AP50–95, APM, and APL aspects also shows varying degrees of improvement; the joint angle detection accuracy under different sports scenarios is tested, and the overall accuracy is improved from 73.2% to 89.0%, which proves the feasibility of the method for posture estimation of the human body in sports and provides a reliable tool for the analysis of athletes’ joint angles.
A review of methods for mapping 3D rotations to one-dimensional planar rotations: analysis, comparison, and a novel efficient Quaternion-based approach
In numerous applications, extracting a single rotation component (termed “planar rotation”) from a 3D rotation is of significant interest. In biomechanics, for example, the analysis of joint angles within anatomical planes offers better clinical interpretability than spatial rotations. Moreover, in parallel kinematics robotic machines, unwished rotations about an axis – termed “parasitic motions” – need to be excluded. However, due to the non-Abelian nature of spatial rotations, these components cannot be extracted by simple projections as in a vector space. Despite extensive discussion in the literature about the non-uniqueness and distortion of the results due to the nonlinearity of the SO(3) group, they continue to be used due to the absence of alternatives. This paper reviews the existing methods for planar-rotation extraction from 3D rotations, showing their similarities and differences as well as inconsistencies by mathematical analysis as well as two application cases, one of them from biomechanics (flexural knee angle in the sagittal plane). Moreover, a novel, simple, and efficient method based on a pseudo-projection of the Quaternion rotation vector is introduced, which circumvents the ambiguity and distortion problems of existing approaches. In this respect, a novel method for determining the orientation of a box from camera recordings based on a two-plane projection is also proposed, which yields more precise results than the existing Perspective 3-Point Problem from the literature. This paper focuses exclusively on the case of finite rotations, as infinitesimal rotations within a single plane are non-holonomic and, through integration, produce rotation components orthogonal to the plane.
Occlusion-Robust Facial Expression Recognition Based on Multi-Angle Feature Extraction
Facial occlusion represents a significant challenge in the domain of facial expression recognition (FER). The absence of feature information due to occlusion has been demonstrated to result in a reduction in recognition accuracy and model robustness. To address this challenge, a multi-angle feature extraction (MAFE) method is proposed in this paper, aiming to enhance the recognition accuracy under occlusion conditions by employing multi-scale global features, local fine-grained features, and important regional features. The MAFE approach involves three core modules: multi-feature extraction, regional detail feature fusion, and consistent feature recognition. In the multi-feature extraction module, PTIR-50 and Swin Transformer are used to extract global features and fine-grained features, and at the same time, the five key points of the face are combined to crop out the important regions from the global features. The Regional Bias Loss (RB-Loss) is then utilized to guide the model to focus on the key information regions. The subsequent Regional Detail Feature Fusion module combines fine-grained features with those from the important regions. This process enhances the expressiveness of the features. The Consistent Feature Recognition module proposes consistent feature loss (con-feature Loss) to ensure that global features and fused features guide each other, forcing the model to focus on more discriminative expression features. The experimental results demonstrate that MAFE attains 89.42% and 86.94% accuracies on the Occlusion-RAFDB and Occlusion-FERPlus datasets, thereby surpassing the existing methods. Accuracies of 92.11% and 90.15% are also obtained on the original RAF-DB and FERPlus datasets.
Evaluation of double-lumen endotracheal tube extubation force by extraction angle: a prospective randomized clinical trial
Gentle and noninvasive double-lumen tracheal tube (DLT) extubation is important for both airway and circulatory management, especially after lung resection. We performed a prospective randomized clinical trial comparing DLT extubation force based on 2 different extraction angles. Randomized clinical trial. Operating room. Sixty adult patients scheduled for elective surgery under general anesthesia using DLT with ASA physical status 1 to 3. Sixty patients who underwent lung resection with a DLT were randomly assigned to extraction angles of 60° (30 patients) and 90° (30 patients) relative to the ground. Extubation forces and changes in vital signs were compared between groups. Results were analysed with the Mann-Whitney U test, non-paired t test, and χ2 test. P<.05 was considered significant. Less extraction force was needed at 60° compared to 90° (90°, 13.9±2.3 N; 60°; 7.1±2.1 N; P<.001). The rate of increase in systolic and diastolic blood pressure (post-extubation/pre-extubation) was significantly smaller at 60° than at 90° (systolic blood pressure, P<.001; diastolic blood pressure, P=.002). Our findings suggest that DLT extubation at 60° requires less force than at 90° and was accompanied by a smaller increase in blood pressure. Thus, extraction at 60° may be less invasive and beneficial for patients undergoing DLT extubation. •Gentle and noninvasive double-lumen tracheal tube (DLT) extubation is important for both pulmonary and circulatory management.•We compared extubation force at 2 extraction angles (60° or 90°) in a prospective randomized clinical trial.•DLT extubation at 60° requires less force than at 90° and was accompanied by a smaller increase in blood pressure.•Extraction at 60° may be less invasive and beneficial for patients undergoing DLT extubation.
Three-dimensional laser scanning under the pinhole camera with lens distortion
This paper proposes a 3D laser scanning technology for the pinhole camera with lens distortion. On the basis of the pinhole camera mathematical model, we improve the extraction algorithm of Harris corner points, and introduce the professional 2D RAC calibration, 3D reconstruction, and 3D volume calculation. With the help of stepper motor, and the camera, we can capture a series of images and obtain the object 3D surface information. Furthermore, we use the line laser with Gaussian distribution as the measurement illuminant, and select the samples at the peak of intensity distribution. This brings both high accuracy and speed of measurement.
UNSUPERVISED ZONING OF CULTIVATION AREAS WITH SIMILAR CULTIVATION PATTERN IN GOLESTAN PROVINCE BASED ON THE VEGETATION PRODUCTS OF MODIS SENSOR
The estimation of cultivation area and categorizing the agricultural product types is one of the prerequisites for achieving sustainable development in the agricultural studies. In this study, an unsupervised zoning the cultivation areas with the same cultivation pattern in Golestan province is on the agenda. Therefore, due to wide spatial range, high temporal resolution and easy access of 16-day products of the vegetation of the MODIS sensor which acquired in a year (From November 2017 to October 2018), these images are used in this research. In the proposed method, after the generating of NDVI vegetation time series as a hyper-cube and separating farmlands’ boundaries in Golestan province using the land-use map; the Sequential Maximum Angle Convex Cone (SMACC) endmember extraction algorithm and the maximum number of product variation using the statistical information of the region (Obtained from the statistics centre of Iran) are used to extract endmembers of the hyper-cube. In the following, the timing responses of the NDVI, identified as endmembers, will be refined in the second phase. In this process, identifying and eliminating noise signals (unrelated to cultivating patterns) and integrating the same cultivating patterns will be on the agenda. At the last stage of the proposed method and after refinement of the endmembers, the hyper-cube is clustered by Spectral Angle Mapper (SAM) algorithm and the mapping of regions with the same cultivation pattern is produced. In the proposed method, the zoning of agricultural land is based solely on the statistical knowledge of the variety of cultivation and the results have led to the production of interconnected spatial parts. This is consistent with the reality of the spatial occurrence of similar cultivating patterns in a geographic area. On the other hand, the visual comparison of results with large scale satellite images illustrates that there is a significant relationship between clustering results and ground truth in terms of cultivating pattern. Obviously, such products can be used as initial layers of information to produce the results of a supervised classification with the aim of applying the cultivation area of a variety of agricultural products.
Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial
Primary angle-closure glaucoma is a leading cause of irreversible blindness worldwide. In early-stage disease, intraocular pressure is raised without visual loss. Because the crystalline lens has a major mechanistic role, lens extraction might be a useful initial treatment. From Jan 8, 2009, to Dec 28, 2011, we enrolled patients from 30 hospital eye services in five countries. Randomisation was done by a web-based application. Patients were assigned to undergo clear-lens extraction or receive standard care with laser peripheral iridotomy and topical medical treatment. Eligible patients were aged 50 years or older, did not have cataracts, and had newly diagnosed primary angle closure with intraocular pressure 30 mm Hg or greater or primary angle-closure glaucoma. The co-primary endpoints were patient-reported health status, intraocular pressure, and incremental cost-effectiveness ratio per quality-adjusted life-year gained 36 months after treatment. Analysis was by intention to treat. This study is registered, number ISRCTN44464607. Of 419 participants enrolled, 155 had primary angle closure and 263 primary angle-closure glaucoma. 208 were assigned to clear-lens extraction and 211 to standard care, of whom 351 (84%) had complete data on health status and 366 (87%) on intraocular pressure. The mean health status score (0·87 [SD 0·12]), assessed with the European Quality of Life-5 Dimensions questionnaire, was 0·052 higher (95% CI 0·015–0·088, p=0·005) and mean intraocular pressure (16·6 [SD 3·5] mm Hg) 1·18 mm Hg lower (95% CI –1·99 to –0·38, p=0·004) after clear-lens extraction than after standard care. The incremental cost-effectiveness ratio was £14 284 for initial lens extraction versus standard care. Irreversible loss of vision occurred in one participant who underwent clear-lens extraction and three who received standard care. No patients had serious adverse events. Clear-lens extraction showed greater efficacy and was more cost-effective than laser peripheral iridotomy, and should be considered as an option for first-line treatment. Medical Research Council.
Three dimensional palatal morphology and dentoalveolar differences after extraction and non extraction treatment in class II malocclusion
Digital technologies have transformed orthodontics by enabling precise three-dimensional (3D) assessment of treatment outcomes; however, the effects of extraction versus non-extraction strategies on palatal morphology in Class II malocclusions remain underexplored. This study quantified segmental palatal volume and surface changes, along with skeletal–dentoalveolar outcomes, using digital model analysis integrated with cephalometrics. Records of 69 post-pubertal patients treated with fixed appliances (Class II, n = 34; Class I controls, n = 35) were retrospectively analyzed, each subdivided into extraction and non-extraction protocols. Maxillary casts were scanned with Sirona inEos X5 and segmented in Materialise 3-Matic to compute palatal volume and surface area, while cephalometric variables were derived from lateral radiographs (Dolphin Imaging). Group comparisons were performed using non-parametric tests ( p  < 0.05). Multivariable regression analyses were conducted to identify dentoalveolar predictors of palatal remodeling. Intra-examiner repeatability was excellent, as indicated by a high intraclass correlation coefficient (ICC ≥ 0.90). Skeletal changes were minimal and comparable across groups. Dentoalveolar findings demonstrated significant maxillary incisor protrusion in non-extraction protocols and retrusion in extraction protocols ( p  < 0.05). Anterior palatal volume and surface area increased across all groups. Overall, measurable differences in total palatal volume and surface area were observed between extraction and non-extraction treatment strategies. Regression analyses indicated that sagittal dentoalveolar displacement was associated with palatal remodeling, whereas angular and vertical dental variables showed limited independent influence. Extraction and non-extraction treatment protocols were associated with measurable differences in three-dimensional palatal volume and surface area, reflecting distinct dentoalveolar and palatal remodeling patterns between treatment strategies.