CNC加工动态基准视觉检测新工艺研究

由于CNC加工过程中工序间误差累积,严重影响数控加工精度。为此提出一种CCD视觉检测新工艺来实现加工动态基准的在线检测和误差补偿。研究动态基准的视觉特征提取方法,获取加工基准位置和误差;采用嵌入式控制技术,实现视觉图像的在线采集和处理;视诊测头像普通刀具一样通过标准锥柄安装在加工中心刀库中,通过CNC程序代码实现一体化控制功能。针对汽车关键件的验证,得出视诊测头检测精度达到0.03 mm,与基于触发式测头的CNC在线检测方法相比,检测效率提高近3倍,证明了该检测工艺在检测精度及效率上均能够满足生产线自动化检测需求。

校园乐乐透测视表

高考体检临近，高度近视的学生小李很着急。老师说：“不用急，把视力表背下来不就行了吗？”于是小李把视力表背得滚瓜烂熟。

雷视融合智能测流系统在河边(二)站的运用分析

本文介绍雷达视频融合智能测流技术,通过雷达测单点流速,与视频测量的流速场融合分析断面流速,然后与流速仪法进行比测分析流量系数0.76,分析结果表明:断面流量标准差为3.0%,随机不确定度为6.0%,系统误差-0.28%,符号检验、适线检验、偏离数值检验均为合格,精度达到相关规范要求,可以运用于类似水文站或河道断面的流量测验;雷视融合测流系统安装简单,利用系统自带电源板和华为5G技术,能实现自动测量和远程传输,可有效解决光纤、市电不宜接入的难题,可有效解决山洪灾害易发区大洪水测验不安全等问题,对建设现代化水文站及智慧水利数字孪生系统具有很好的支撑作用。

利用井下不通视测点的测量方法

主要介绍的是如何利用井下不通视测点,进行井巷测量,标定中腰线,该方法方便快捷,减少工作量,同时也适用地面控制测量,实用性强。

三维OBS探测实验中炮点和OBS位置校正新方法

炮点和海底地震仪(ocean bottom seismometer,OBS)位置校正是三维地震数据处理的基本环节,也是获取高精度三维速度结构的关键所在.本文基于南海洋陆转换带(Continental-Oceanic-Transition zone,COT)IODP367/368钻探区开展的三维OBS深地震探测数据,开展了炮点及OBS位置校正研究,新的校正方法主要体现在三个方面:(1)利用连续三个炮点的平均航向对中间炮点进行位置校正,更真实地反映气枪枪阵与船体之间的软连接状态;(2)根据"滑动窗口"思想将海水声学速度阈值划分成N等份,通过循环测试获得全局最优的OBS位置校正结果,改进了前人方法只能获得局部最优解的问题;(3)针对单条测线穿过的OBS,通过加入其临近测线的直达水波走时,构成视双测线OBS位置校正法,提高了校正精度.49台OBS位置校正结果表明,除3台单测线法校正的OBS在垂直测线方向存在较大不确定性外,其余误差范围均为35m左右.本文改进的OBS位置校正方法,不仅提高了单条测线穿过的OBS位置校正精度,保证后续三维地震结构研究的可靠性,而且为今后类似的OBS位置校正提供了经验和借鉴.

前方交会在矿山测量中的应用

井下条件复杂经常无法通视,贯通时需要提前得出待测点坐标,前方交会公式复杂不易记忆,利用二元一次方程组可使用计算器直接求出交会点坐标,提高了工作效率,是矿山测量中求前方交会的简便方法。

Development status and prospect of cold chain logistics of fruits,vegetables,and agricultural products based on intelligent technology

The cold chain in the production area of fruits and vegetables is the primary link to reduce product loss and improve product quality,but it is also a weak link.With the application of big data technology in cold chain logistics,intelligent devices,and technologies have become important carriers for improving the efficiency of cold chain logistics in fruit and vegetable production areas,extending the shelf life of fruits and vegetables,and reducing fruit and vegetable losses.They have many advantages in fruit and vegetable pre-cooling,sorting and packaging,testing,warehousing,transportation,and other aspects.This article summarizes the rapidly developing and widely used intelligent technologies at home and abroad in recent years,including automated guided vehicle intelligent handling based on electromagnetic or optical technology,intelligent sorting based on sensors,electronic optics,and other technologies,intelligent detection based on computer vision technology,intelligent transportation based on perspective imaging technology,etc.It analyses and studies the innovative research and achievements of various scholars in applying intelligent technology in fruit and vegetable cold chain storage,sorting,detection,transportation,and other links,and improves the efficiency of fruit and vegetable cold chain logistics.However,applying intelligent technology in fruit and vegetable cold chain logistics also faces many problems.The challenges of high cost,difficulty in technological integration,and talent shortages have limited the development of intelligent technology in the field of fruit and vegetable cold chains.To solve the current problems,it is proposed that costs be controlled through independent research and development,technological innovation,and other means to lower the entry threshold for small enterprises.Strengthen integrating intelligent technology and cold chain logistics systems to improve data security and system compatibility.At the same time,the government should introduce relevant policies,provide necessary financial support,and establish talent training mechanisms.Accelerate the development and improvement of intelligent technology standards in the field of cold chain logistics.Through technological innovation,cost control,talent cultivation,and policy guidance,we aim to promote the upgrading of the agricultural industry and provide ideas for improving the quality and efficiency of fruit and vegetable cold chain logistics.

DEMAND-PULLED AIRCRAFT SPARE PART PROGNOSTICATION AND CONTROL STRATEGY

This paper presents a control strategy of demand pulled spare parts inventory. It establishes a spare part demand prognosticating model based on reliability analysis. Through parts reliability data the model gets the reliable life function of spare parts and determines parts demand time, depending on part life at given reliabilities. Moreover, a case study is taken to illuminate the demand prognostication and inventory control of on condition maintenance rotables.

Embedded Remote Monitoring System of Agricultural Environment Based on DSP

Agricultural environmental remote monitoring,data collection and network transmission are the development directions of modern agriculture.The embedded video remote monitoring system is designed with DSP processor DM642,which can collect the video signal of agricultural environment and biological information,as well as complete the extraction of video signal and network transmission.This system can be applied to the agro-ecological and environmental resources monitoring,agricultural disaster monitoring and warning and other digital agricultures.

Feature-based sequential partial vision measurement method for large scale machine parts

To realize the high-precision vision measurement for large scale machine parts, a new vision measurement method based on dimension features of sequential partial images is proposed. Instead of mosaicking the partial images, extracting the dimension features of the sequential partial images and deriving the part size according to the relationships between the sequential images is a novel method to realize the high- precision and fast measurement of machine parts. To overcome the corresponding problems arising from the relative rotation between two sequential partial images, a rectifying method based on texture features is put forward to effectively improve the processing speed. Finally, a case study is provided to demonstrate the analysis procedure and the effectiveness of the proposed method. The experiments show that the relative error is less than 0. 012% using the sequential image measurement method to gauge large scale straight-edge parts. The measurement precision meets the needs of precise measurement for sheet metal parts.

Design of a road vehicle detection system based on monocular vision

In order to decrease vehicle crashes, a new rear view vehicle detection system based on monocular vision is designed. First, a small and flexible hardware platform based on a DM642 digtal signal processor （DSP） micro-controller is built. Then, a two-step vehicle detection algorithm is proposed. In the first step, a fast vehicle edge and symmetry fusion algorithm is used and a low threshold is set so that all the possible vehicles have a nearly 100% detection rate （TP） and the non-vehicles have a high false detection rate （FP）, i. e., all the possible vehicles can be obtained. In the second step, a classifier using a probabilistic neural network （PNN） which is based on multiple scales and an orientation Gabor feature is trained to classify the possible vehicles and eliminate the false detected vehicles from the candidate vehicles generated in the first step. Experimental results demonstrate that the proposed system maintains a high detection rate and a low false detection rate under different road, weather and lighting conditions.

Computer vision technology in log volume inspection

Log volume inspection is very important in forestry research and paper making engineering. This paper proposed a novel approach based on computer vision technology to cope with log volume inspection. The needed hardware system was analyzed and the details of the inspection algorithms were given. A fuzzy entropy based on image enhancement algorithm was presented for enhancing the image of the cross-section of log. In many practical applications the cross-section is often partially invisible, and this is the major obstacle for correct inspection. To solve this problem, a robust Hausdorff distance method was proposed to recover the whole cross-section. Experiment results showed that this method was efficient.

Visual Identification Method and Implementation of Impurities in Food Grain

A method to check impurities in food grain based on digital image processing is proposed in this study. According to the feature of the impurity, one image with twice processing is put forward based on blob analysis, which eliminates impurities that were brighter or darker than normal particles. With the image processing system developed by Matrox Imaging Library, black and white blobs are extracted for twice with one function, and then the size and the position of impurities are calculated quickly through mathematical morphologic and blob analysis. The method can be extended and applied in other fields due to its advantages of quick speed and high accuracy.

Video-based urban expressway traffic measurement and performance monitoring

This paper presents an urban expressway video surveillance and monitoring system for traffic flow measurement and abnormal performance detection. The proposed flow detection module collects traffic flow statistics in real time by leveraging multi-vehicle tracking information. Based on these online statistics, road operating situations can be easily obtained. Using spatiotemporal trajectories, vehicle motion paths are encoded by hidden Markov models. With path division and parameter matching, abnormal performances containing extra low or high speed driving, illegal stopping and turning are detected in real scenes. The traffic surveillance approach is implemented and evaluated on a DM642 DSP-based embedded platform. Experimental results demonstrate that the proposed system is feasible for the detection of vehicle speed, vehicle counts and road efficiency, and it is effective for the monitoring of the aforementioned anomalies with low computational costs.

RESEARCH ON 3 D RANGE SENSOR SYSTEM

The structure of 3 D range sensor system for unmanned vehicle is introduced.Several key technologies are described in detail.The ultrasonic signal is processed from different angles.Image edges are extracted by the multiple scale method.Image noises are recognized and cleared by using multilayer forward neural network with fuzzy logic.The method of information fusion for multiple sensors is discussed.This paper also gives some ultrasonic signal curves and image results.

NEW CORNER DETECTION ALGORITHM BASED ON MULTI-FEATURE SYNTHESIS

Corner detection is a chief step in computer vision. A new corner detection algorithm in planar curves is proposed. Firstly, from the human perception, two key characteristics are given as an amendment of the traditional corner properties. Based on the two properties, the concept of the fuzzy set is introduced into a detection. Secondly, the extracted-formulae of three groups including the features of the corner subject degree are derived. Through synthesizing the features of three groups, the judgments of the corner detection, location, and optimization are obtained. Finally, by using the algorithm the detection results of several examples and feature curves for some interested parts, as well as the detection results for the test images history in references are given. Results show that the algorithm is easily realized after adopting the fuzzy set, and the detection effect is very ideal.

Contrast Detection Learning Improves Visual Contrast Sensitivity of Cat

Psychological studies on human subjects show that contrast detection learning promote learner＇s sensitivity to visual stimulus contrast. The underlying neural mechanisms remain unknown. In this study, three cats （Felis catus） were trained to perform monocularly a contrast detection task by two-altemative forced choice method. The perceptual ability of each cat improved remarkably with learning as indicated by a significantly increased contrast sensitivity to visual stimuli. The learning effect displayed an evident specificity to the eye employed for learning but could partially transfer to the naive eye, prompting the possibility that contrast detection learning might cause neural plasticity before and after the information from both eyes are merged in the visual pathway. Further, the contrast sensitivity improvement was evident basically around the spatial frequency （SF） used for learning, which suggested that contrast detection learning effect showed, to some extent, a SF specificity. This study indicates that cat exhibits a property of contrast detection learning similar to human subjects and can be used as an animal model for subsequent investigations on the neural correlates that mediate learning-induced contrast sensitivity improvement in humans.

METHODS OF VISUAL RECOGNITION,POSITIONING AND ORIENTATING OF 3 D SIMPLE GEOMETRIC WORKPIECE

The methods of visual recognition,positioning and orienting with simple 3 D geometric workpieces are presented in this paper.The principle and operating process of multiple orientation run length coding based on general orientation run length coding and visual recognition method are described elaborately.The method of positioning and orientating based on the moment of inertia of the workpiece binary image is stated also.It has been applied in a research on flexible automatic coordinate measuring system formed by integrating computer aided design,computer vision and computer aided inspection planning,with a coordinate measuring machine.The results show that integrating computer vision with measurement system is a feasible and effective approach to improve their flexibility and automation.

A new method for specular curved surface defect inspection based on reflected pattern integrity

Defect inspection of specular curved surface is a challenging job. Taking steel balls for example, a new method based on reflected pattern integrity recognition is put forward. The specular steel ball surface will totally reflect the patterns when it is placed inside a dome-shaped light source, whose inner wall is modified by patterns with certain regular. Distortion or intermittence of reflected pattern will occur at the defective part, which indicates the pattern has lost its integrity. Based on the integrity analysis of reflected pattern images？ surface defects can be revealed. In this paper, a set of concentric circles are used as the pattern and an image processing algorithm is customized to extract the surface defects. Results show that the proposed method is effective for the specular curved surface defect inspection