多尺度光点图像中心的高精度定位

提出了一种可快速、高精度提取不规则光点图像中心的多尺度光点图像中心定位方法。首先,结合图像形态学处理和阈值分割确定光点图像区域,初步确定光点图像大小;然后,计算不同尺度空间下各光点图像区域的Hessain矩阵,由Hessain矩阵特征值确定的判决系数确定最佳尺度,并确定光点图像中心像素级坐标;最后,根据光点区域周边图像二阶泰勒展开式求解光点图像中心亚像素坐标。仿真和实物实验表明,本文算法抗噪声能力强、可实现不同大小光点图像中心的快速高精度定位。在实物试验中,该方法提取光点图像中心的精度优于0.1pixel。目前,该方法已在多套视觉测量系统中得到应用。

视觉测量红外光点图像中心精确提取

提出了一种视觉测量中的红外光点图像中心提取方法。首先,使用一组阈值平面与红外光点灰度能量分布相交确定光点能量等高线,得到各等高轮廓点和阈值平面截得的能量包络。然后,利用最小二乘椭圆拟合等高线上轮廓点的椭圆中心,并计算阈值平面所截得的能量包络的质心,以椭圆中心和包络质心的黄金分割点作为等高层面上的光点中心。最后,利用各等高层面光点的中心获得红外光点图像中心的精确位置。试验验证结果表明,算法对红外光点图像中心提取可取得较高精度。目前,方法已在面阵静态红外地球敏感器标定中得到应用。

Method for Detecting Weld Feature Size Based on Line Structured Light

With the rapid development of the machining and manufacturing industry,welding has been widely used in forming connections of structural parts.At present,manual methods are often used for welding and quality inspection,with low efficiency and unstable product quality.Due to the requirements of visual inspection of weld feature size,a visual inspection system for weld feature size based on line structured light(LSL)is designed and built in this paper.An adaptive light stripe sub-pixel center extraction algorithm and a feature point extraction algorithm for welding light stripe are proposed.The experiment results show that the detection error of the weld width is 0.216 mm,the detection error of the remaining height is 0.035 mm,the single measurement costs 109 ms,and the inspection stability and repeatability of the system is 1%.Our approach can meet the online detection requirements of practical applications.

Research on Visual Detection Algorithm for Groove Feature Sizes by Means of Structured Light Projection

The visual inspection is an economical and effective method for welding. For measuring the feature sizes of grooves,a method based on line structured light is presented. Firstly,an adaptive algorithm to extract the subpixel centerline of structured light stripes is introduced to deal with the uneven width and grayscale distributions of laser stripes,which is based on the quadratic weighted grayscale centroid. By means of region-of-interest(ROI)division and image difference,an image preprocessing algorithm is developed for filtering noise and improving image quality. Furthermore,to acquire geometrical dimensions of various grooves and groove types precisely,the subpixel feature point extraction algorithm of grooves is designed. Finally, experimental results of feature size measuring show that the absolute error of measurement is 0.031—0.176 mm,and the relative error of measurement is 0.2%—3.6%.

Progress in small-molecule luminescent materials for organic light-emitting diodes

Organic light-emitting diodes （OLEDs） have been extensively studied since the first efficient device based on small molecular luminescent materials was reported by Tang. Organic electroluminescent material, one of the centerpieces of OLEDs, has been the focus of studies by many material scientists. To obtain high luminosity and to keep material costs low, a few remarkable design concepts have been developed. Aggregation-induced emission （AIE） materials were invented to overcome the common fluorescence-quenching problem, and cross-dipole stacking of fluorescent molecules was shown to be an effective method to get high solid-state luminescence. To exceed the limit of internal quantum efficiency of conventional fluorescent materials, phosphorescent materials were successfully applied in highly efficient electroluminescent devices. Most recently, delayed flu- orescent materials via reverse-intersystem crossing （RISC） from triplet to singlet and the ＂hot exciton＂ materials based on hy- bridized local and charge-transfer （HLCT） states were developed to he a new generation of low-cost luminescent materials as efficient as phosphorescent materials. In terms of the device-fabrication process, solution-processible small molecular lumi- nescent materials possess the advantages of high purity （vs. polymers） and low procession cost （vs. vacuum deposition）, which are garnering them increasing attention. Herein, we review the progress of the development of small-molecule luminescent materials with different design concepts and features, and also briefly examine future development tendencies of luminescent materials.

新起点:PF98式120mm反坦克火箭(下)

本文上篇介绍了PF98式120mm火箭的发射筒及三脚架,下篇继续展示其各种瞄准装置及附件——技术起点高,开创新篇章(续)瞄准装置瞄准装置是PF98式120mm火箭的核心部件之一,主要用于装定射击诸元,对目标实施瞄准。营用型火箭的瞄准装置包括简易火控系统及微光瞄准镜,连用型火箭的瞄准装置包括白光瞄准镜及微光瞄准镜。