This paper investigates a method for the multi-threshold segmentation of grayscale imaging using the local minimum points of a histogram curve as the segmentation threshold. By smoothing the histogram curve and judging the conditions, the expected peaks and valleys are identified, and the corresponding minimum points are used as segmentation thresholds to achieve fast multi-threshold image segmentation. Compared to the OTSU method (maximum between-class variance) for multi-threshold segmentation and the region growing method, this method has less computational complexity. In the recognition and segmentation process of solder pads with adhesion of underfill in LED Chips, the segmentation time is less than one percent of that of the OTSU method and the region growing method. The segmentation effect is better than the OTSU method and the region growing method, and it can achieve fast multi-threshold segmentation of images. Moreover, it has strong adaptability to the differences in the overall grayscale of images, meeting the requirements for high UPH (Units Per Hour) in industrial production lines.

The mechanism of the combined process of ion beam sputtering (IBS) and HF acid etching on the chemical structure defects of fused silica and its laser damage resistance performance were investigated in this paper. During the removal process of surface material, the sputtering effect causes lattice atoms to flee their native space locations, and a large amount of unsaturated chemical structures are produced on the silica surface, which improves the chemical activity of Si and O atoms, accelerates the chemical reaction process between surface atoms and water molecules, increases the content of hydroxyl groups (OH-) in the shallow layer, and enhances the photothermal weak absorption intensity. However, the increase in hydroxyl content weakens the binding strength of silicon–oxygen bonds, destroys the spatial network structure of silica bulk, and reduces its mechanical strength, resulting in a decrease in its laser damage resistance performance. The paper reveals for the first time the mechanism by which IBS changes the structure characteristics of silica material, accelerates the surface hydroxylation process, and thereby reduces the laser damage resistance performance. This work provides technical guidance for effectively suppressing chemical structure defects on silica surfaces and improving the laser damage resistance performance of optical components under high-flux laser irradiation.

In this paper, the mechanism of combined process of ion beam sputtering (IBS) and HF acid etching on the chemical structure defects of fused silica and its laser damage resistance perfor-mance were investigated. During the removal process of surface material, the sputtering effect causes lattice atoms to detach from their original positions, forming a large number of unsaturated structures on silica surface, which improves the chemical activity of Si and O atoms, accelerates the chemical reaction process between surface atoms and water molecules, increases the content of hydroxyl (OH-) groups in the shallow layer, and enhances the photothermal weak absorption intensity. However, the presence of OH- groups reduces the bonding strength of Si-O, destroys the spatial network structure of silica bulk, and reduces the mechanical strength of silica surface, resulting in a decrease in its laser damage resistance performance. The paper reveals for the first time the mechanism of IBS to change the structure characteristics of silica material, accelerate the surface hydroxylation process, and thereby reduces the laser damage resistance performance. This work provides technical guidance for effectively suppressing chemical structure defects on silica surface and improving laser damage resistance performance of optical components under high-flux laser irradiation.

In multi-AUV collaborative underwater coverage operations, the fundamental principle of load balancing is temporally rather than spatially defined. Traditional partition schemes that equalize area or grid counts suffer from a critical fallacy: they assume a linear mapping from geometry to working time, which collapses in the presence of irregular obstacles. This paper demonstrates that temporal load imbalance causes some AUVs to finish prematurely and remain idle—consuming power and fighting currents while their counterparts struggle with topologically complex sub-regions. To address this, we propose a dual-layer nested Particle Swarm Optimization (PSO) framework for Voronoi partitioning, where the outer layer coarsely initializes grid counts, while the inner layer directly minimizes the makespan and time variance derived from actual BINN-simulated coverage paths. This two-stage PSO architecture effectively resolves the nonlinear mismatch between geometric partitioning and real operation time, redefining load balancing from a geometrical abstraction to a temporally grounded, operationally relevant metric. Furthermore, we rigorously distinguish the intrinsic nature of coverage path planning (CPP) from Traveling Salesman Problem (TSP)-based point routing—the latter generates discontinuous, sharp-turning trajectories that violate the kinematic constraints of side-scan sonar payloads and cause critical data gaps. The proposed architecture yields a standard deviation of mission times that is an order of magnitude lower than area-based heuristics, while maintaining kinematically feasible continuous sweeps. Crucially, we explicitly delineate the operational boundary of this framework: it is purpose-built for static, pre-surveyed environments where offline computational overhead (approximately 8 min) is a justifiable investment against a 3 h optimal field execution.