Introduction: Asian soybean rust is a highly aggressive leaf-based disease triggered by the obligate biotrophic fungus Phakopsora pachyrhizi which can cause up to 80% yield loss in soybean. The precise image segmentation of fungus can characterize fungal phenotype transitions during growth and help to discover new medicines and agricultural biocides using large-scale phenotypic screens.Methods: The improved Mask R-CNN method is proposed to accomplish the segmentation of densely distributed, overlapping and intersecting microimages. First, Res2net is utilized to layer the residual connections in a single residual block to replace the backbone of the original Mask R-CNN, which is then combined with FPG to enhance the feature extraction capability of the network model. Secondly, the loss function is optimized and the CIoU loss function is adopted as the loss function for boundary box regression prediction, which accelerates the convergence speed of the model and meets the accurate classification of high-density spore images.Results: The experimental results show that the mAP for detection and segmentation, accuracy of the improved algorithm is improved by 6.4%, 12.3% and 2.2% respectively over the original Mask R-CNN algorithm.Discussion: This method is more suitable for the segmentation of fungi images and provide an effective tool for large-scale phenotypic screens of plant fungal pathogens.
The purpose of this study is to obtain the digital twin parameters of the thyroid gland and to build a constitutional model of the thyroid gland based on continuum mechanics, which will lay the foundation for the establishment of a surgical training system for the thyroid surgery robot and the development of the digital twin of the thyroid gland. First, thyroid parenchyma was obtained from fresh porcine thyroid tissue and subjected to quasi-static unconfined uniaxial compression tests using a biomechanical test platform with two strain rates (0.005 s−1 and 0.05 s−1) and two loading orientations (perpendicular to the thyroid surface and parallel to the thyroid surface). Based on this, a tensile thyroid model was established to simulate the stretching process by using the finite element method. The thyroid stretching test was carried out under the same parameters to verify the validity of the hyperelastic constitutive model. The quasi-static mechanical property parameters of the thyroid tissue were obtained by a quasi-static unconstrained uniaxial compression test, and a constitutional model that can describe the quasi-static mechanical properties of thyroid tissue was proposed based on the principle of continuum media mechanics, which is of great value for the establishment of a surgical training system for the head and neck surgery robot and for the development of the thyroid digital twin.
20 January 2025 in Journal of Mechanisms and Robotics
Ultrasound-guided percutaneous puncture technology has advantages such as intra-operative real-time imaging, noninvasive operation, high targeting accuracy, nonionizing radiation, and low cost. However, traditional percutaneous puncture surgery requires doctors to hold ultrasound probes or puncture needles, which causes complex operations. In this article, by integrating ultrasound and needle insertion mechanisms, an ultrasound-guided miniature puncture robot is proposed. This robot can work without an external navigation or industrial or cooperative manipulator after hand-eye calibration and acknowledge the coordinate relationship between the ultrasound image and the robot tip. A three degrees-of-freedom (DoFs) of in-plane mechanism using linear actuators is designed so that the puncture needle can always be scanned by ultrasound during the operation, ensuring real-time monitoring. The method of planning puncture path, modeling the robot kinematics, and ultrasound hand-eye calibration are proposed. To track a needle in an ultrasound image, the image recognition and filter algorithm for the needle tip are presented. The accuracy of the robot puncture operation is verified by point targeting and path tracking experiments in the water tank and phantom, and the puncture error of the robot is 1.5 ± 0.5 mm in the water tank, 1.98 mm in the abdominal phantom, and 1.41 mm in the breast phantom. Finally, the work of this article effectively improves the availability and effectiveness of the ultrasound-guided puncture robot.
To address the challenges of confined workspaces and high-precision requirements in thyroid surgery, this paper proposes a modular cable-driven robotic system with a hybrid rigid–continuum structure. By integrating rigid mechanisms and continuum joints within a closed-loop cable-driven framework, the system achieves a balance between flexibility in narrow spaces and operational stiffness. To tackle kinematic model inaccuracies caused by manufacturing errors, an innovative joint decoupling strategy combined with the Particle Swarm Optimization (PSO) algorithm is developed to dynamically identify and correct 19 critical parameters. Experimental results demonstrate a 37.74% average improvement in repetitive positioning accuracy and a 52% reduction in maximum absolute error. However, residual positioning errors (up to 4.53 mm) at motion boundaries highlight the need for integrating nonlinear friction compensation. The feasibility of a safety-zone-based force feedback master–slave control strategy is validated through Gazebo simulations, and a ring-grasping experiment on a surgical training platform confirms its clinical applicability.