Visual navigation in orchard based on multiple images at different shooting angles

The orchards usually have rough terrain,dense tree canopy and weeds.It is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency interference.To achieve autonomous navigation in orchard,a visual navigation method based on multiple images at different shooting angles is proposed in this paper.A dynamic image capturing device is designed for camera installation and multiple images can be shot at different angles.Firstly,the obtained orchard images are classified into sky and soil detection stage.Each image is transformed to HSV space and initially segmented into sky,canopy and soil regions by median filtering and morphological processing.Secondly,the sky and soil regions are extracted by the maximum connected region algorithm,and the region edges are detected and filtered by the Canny operator.Thirdly,the navigation line in the current frame is extracted by fitting the region coordinate points.Then the dynamic weighted filtering algorithm is used to extract the navigation line for the soil and sky detection stage,respectively,and the navigation line for the sky detection stage is mirrored to the soil region.Finally,the Kalman filter algorithm is used to fuse and extract the final navigation path.The test results on 200 images show that the accuracy of visual navigation path fitting is 95.5%,and single frame image processing costs 60 ms,which meets the real-time and robustness requirements of navigation.The visual navigation experiments in Camellia oleifera orchard show that when the driving speed is 0.6 m/s,the maximum tracking offset of visual navigation in weed-free and weedy environments is 0.14 m and 0.24 m,respectively,and the RMSE is 30 mm and 55 mm,respectively.

The Study of Relationships between the Damage of Visual Function and Hemorrheology, Ocular Rheography, as well as Other Related Factors in Patients with Primary Open Angle Glaucoma (POAG)

Researches of glaucoma visual function damage, hemorrheololgy, ocular rheography and other related multiplex factors, with computed multifactorial stepwise regresion analysis, indicate that the elevation of intraocular pressure (IOP) is not the only factor to induce visual impairment. POAG patients are shown to have markedly reduced diastolic purfussion pressure in ophthalmic artery, besides prolonged filling time of the retinal artery and vein, diminished erythrocyte deformability and increased platele...

Bifurcation analysis of visual angle model with anticipated time and stabilizing driving behavior

In the light of the visual angle model(VAM),an improved car-following model considering driver's visual angle,anticipated time and stabilizing driving behavior is proposed so as to investigate how the driver's behavior factors affect the stability of the traffic flow.Based on the model,linear stability analysis is performed together with bifurcation analysis,whose corresponding stability condition is highly fit to the results of the linear analysis.Furthermore,the time-dependent Ginzburg–Landau(TDGL)equation and the modified Korteweg–de Vries(m Kd V)equation are derived by nonlinear analysis,and we obtain the relationship of the two equations through the comparison.Finally,parameter calibration and numerical simulation are conducted to verify the validity of the theoretical analysis,whose results are highly consistent with the theoretical analysis.

Research on the Novel Mode of Plane Graphic Design from the Angle of Visual Language Transmitting

In this paper, we conduct research on the novel mode of plane graphic design from the core angle of the primary visual language transmitting. Relationship between nationality and cosmopolitan processing in graphic design in the design of image symbol expression and significance of the symbol on the one hand require symbolic form must have enough openness and the cognitive function on the other hand with semiotics method can let the designer to extract the most representative and symbolic notation style to carry on the design expression. As a non- verbal symbols, from the perspective of the view, the design image is no national boundaries, but the human form to beauty and should express the symbolism of cognition is the same. In the form of the ethnic groups of the cosmopolitan codes are for identification of Chinese contemporary design possible effective methods. Our research proposes novel perspective of the design which is meaningful.

On China＇s Economy： A Tentative Research from a Dual Visual Angle

Most economists approach the economy of China from a single visual angle considering it as a special economic modality of transition economy. Based on the analysis from the single visual angle, the paper puts forward a dual visual angle treating China＇s economy as one of both transition and transformation features, and attempts to research it from this dual visual angle.

青少年特发性脊柱侧弯治疗的可视化分析

背景:目前脊柱侧弯发病率正在逐年上升,尤以青少年特发性脊柱侧弯最为常见。因此加强对青少年脊柱侧弯治疗的研究就显得越来越重要。目的:旨在总结全球关于青少年特发性脊柱侧弯治疗研究的现状、热点、新兴趋势以及前沿,为今后相关的研究提供参考及指导。方法:从Web of Science核心集数据库中检索2013-2023年有关青少年特发性脊柱侧弯治疗的文献。运用CiteSpace 6.2.R1软件对国家、机构、作者和关键词进行可视化分析。结果与结论:①共纳入561篇英文文献,在国家、机构及作者分析中,美国的贡献最为突出,南京大学及Qiu Yong(南京大学医学院附属鼓楼医院)是发文量最多的机构及作者,发文量最多的学术期刊是《European Spine Journal》。②在被引用文献分析中,引用量前10位的文章主要描述了手术治疗与保守治疗对于改善青少年特发性脊柱侧弯的效果,尤以改善患者曲度为著,③通过对高被引文章进行归纳总结以及对关键词聚类、关键词突现进行深入挖掘发现,目前的研究热点是Cobb角与治疗方法选择的关系、运动疗法的治疗效果与椎体后路融合术的治疗效果。④对于不同曲度的患者,预后情况是否一致未有深入研究,以及青少年特发性脊柱侧弯的病因尚未明确,因此曲率与预后的关系以及青少年特发性脊柱侧弯的病因可能是未来新的研究趋势。

The Exact Estimation of Visual Acuity by VEP Technology:A Report of 726 Cases of Eye Injury

This study explored the accuracy of using visual evoked potentials(VEP)technology for visual acuity estimation.The enrolled 726 patients with post-traumatic unilateral decrease in visual acuity included the injured eyes served as the experimental group,and the healthy eyes as the control group.The least signal visual angle(LSVA),and amplitude and latency of P100 were chosen as test indexes.The results under different experimental conditions were recorded by PRVEP technology.All data collected were processed...

Visualizing experimental investigation on gas-liquid replacements in a microcleat model using the reconstruction method

Cleats are the main channels for fluid transport in coal reservoirs.However,the microscale flow characteristics of both gas and water phases in primary cleats have not been fully studied as yet.Accordingly,the local morphological features of the cleat were determined using image processing technology and a transparent cleat structure model was constructed by microfluidic lithography using the multiphase fluid visualization test system.Besides,the effect of microchannel tortuosity characteristics on two‐phase flow was analyzed in this study.The results are as follows:(1)The local width of the original cleat structure of coal was strongly nonhomogeneous.The cleats showed contraction and expansion in the horizontal direction and undulating characteristics in the vertical direction.(2)The transient flow velocity fluctuated due to the structural characteristics of the primary cleat.The water‐driven gas interface showed concave and convex instability during flow,whereas the gas‐driven water interface presented a relatively stable concave surface.(3)The meniscus advanced in a symmetrical pattern in the flat channel,and the flow stagnated due to the influence of undulation points in a partially curved channel.The flow would continue only when the meniscus surface bypassed the stagnation point and reached a new equilibrium position.(4)Enhanced shearing at the gas-liquid interface increased the gas‐injection pressure,which in turn increased residual liquids in wall grooves and liquid films on the wall surface.

Head Position of Patients with Right Hemisphere Damage during a Visual Search Task in a Large Field

Spatial neglect syndrome with cerebral lesions is characterized by the ina-bility to orient, report, or respond to relevant visual stimuli contralateral to the lesions. In this study, we investigated the pattern of horizontal visual search in a large space;this search was performed by patients with right hemisphere damage caused by cerebrovascular disease. The neck rotation angle and search time in each increment were continuously recorded during the task, and quantitative data of the measurements were collected. Head position during the visual search task in a large space (%) was then calculated. We set angular bands in increments of 5 degrees from the midline on the left and right sides, and calculated the total search time in each angular band. In patients with unilateral spatial neglect (USN), the search time in the angular band of 5 - 9 on the right side was significantly longer (with USN 16.7%, without USN 4.5%, t = 2.52, df = 16, p < 0.05). Furthermore, in patients with neglect in the leftmost end area in a large space, the search time was significantly shorter in the angular band of 1 - 4 degrees to the left (with neglect 13.1%, without neglect 23.7%, t = 2.13, df = 16, p < 0.05), and tended to be long in the angular band of 5 - 9 to the right. The neck rotation angle and pattern during the search task in a large field deviated slightly to the right, and the search time slightly to the left was short. We believe that these results support the rightward deviation of the search pattern and frame of USN patients.

激光周边虹膜切除术在原发性急性闭角型青光眼患者中的应用效果及对眼压和视力的影响

目的探讨激光周边虹膜切除术在原发性急性闭角型青光眼患者中的应用效果及对眼压和视力的影响。方法以随机法选取2020年10月至2022年10月的80例(86眼)原发性急性闭角型青光眼患者作为研究对象,所有患者给予激光周边虹膜切除术治疗。观察患者术前、术后的眼压、视力水平、房角关闭情况及角膜内皮细胞指标。结果术后,患者的眼压低于术前,视力水平高于术前(P<0.05)。术后,患者的前房角角度(ACA)、前房容积(ACV)和周边前房深度(PACD)均显著大于术前(P<0.05);术后,患者的中央前房深度(CACD)与术前比较,差异无统计学意义(P>0.05)。术后,患者的平均内皮细胞面积(AVE)、最大细胞面积(MAX)、最小细胞面积(MIN)、细胞密度(CD)、变异系数(CV)及细胞面积标准差(SD)与术前比较,差异无统计学意义(P>0.05)。结论原发性急性闭角型青光眼患者早期给予激光周边虹膜切除术治疗对降低眼压有明显效果,且还能提升视力水平,改善房角关闭情况,对患者角膜内皮细胞的损伤较小,安全性较高。

超声波干涉及可视化实验装置研制

为了丰富大学物理声学实验内容,研制了一种多功能超声波干涉实验装置。基于空气介质设计了双振子干涉声速测量实验和半波损失验证实验。分别采用干涉声场测量法和干涉条纹移动法进行声速测量实验,并利用示波器实现了干涉声场声压分布的可视化。分别以有机玻璃、橡胶和玻璃为反射面材料,利用干涉法验证掠入射条件下的半波损失现象,并估算出掠入射角的范围。该实验装置实验现象明显、可操作性强,获评北京市第十六届大学生物理实验竞赛一等奖。

一种广角相机视频小卫星姿态跟踪方法

针对传统目标跟踪方法需要目标的先验位置信息、不适用于非合作目标跟踪的问题,提出了一种基于广角相机图像误差的视频小卫星目标跟踪方法。该方法首先建立了广角相机成像模型,然后计算目标在相机图像平面中的投影位置和期望位置之差,通过图像误差确定目标与视频小卫星的相对误差角速度和姿态误差,将其作为反馈项设计非线性控制器,最后利用Barbalat引理证明了系统的稳定性。仿真结果表明,在广角相机大范围视场下,该方法可以有效地将目标控制到图像平面中期望的位置,并且利用天拓二号卫星在轨验证了该方法的有效性。

原发性开角型青光眼发病机制的文献计量学研究

目的:通过对近30 a原发性开角型青光眼(POAG)发病机制的相关文献进行计量学分析,了解该领域的发文情况、研究趋势及研究前沿和热点。方法:检索1993-09-01/2023-09-01在中国知网(CNKI)和Web of Science(WOS)核心数据库已发表的关于POAG发病机制的相关文献986篇,运用CiteSpace(6.2.R.4)和VOSviewer(1.6.18)软件对检索到的文献进行知识图谱分析,分析内容包括发文量、作者、研究机构、国家/地区及关键词。结果:美国发文量最多(243篇),其次是中国(121篇)。发文量最多的国外研究机构是哈佛大学(37篇),国内研究机构中山医科大学中山眼科中心、首都医科大学宣武医院眼科、北京医科大学第一医院眼科发文量并列第一。Louis R. Pasquale(21篇)是最高产的英文作者,王宁利是该领域最活跃的中国研究者。该领域研究的关键词包括小梁网、眼压、房水、糖皮质激素、血液流变学等。结论:POAG发病机制的研究正处于蓬勃发展期,美国在该领域发文量最大,哈佛大学为该领域的领先研究机构。POAG研究领域的研究重点已经从结构方面转移到了基因层面,基因研究与中医治疗在该领域具有广泛的应用前景。

晶状体超声乳化术治疗早期闭角型青光眼的效果观察

目的观察在早期闭角型青光眼治疗中使用晶状体超声乳化术所取得的治疗效果。方法选取2022年3月—2023年3月在本院接受治疗的早期闭角型青光眼患者80例为研究样本,采用随机法分两组,每组40例。采用晶状体超声乳化术治疗的作为观察组,采用周边虹膜切除治疗法的作为对照组,对比术前、后视力水平,并发症发生率,术前、后中央前房深度及眼压。结果术前,两组的视力水平对比,差异无统计学意义(P>0.05);术后,观察组的视力水平低于对照组,并发症发生率低于对照组,组间差异有统计学意义(P<0.05)。术前,两组中央前房深度及眼压对比,差异无统计学意义(P>0.05);术后,观察组中央前房深度及眼压低于对照组,组间差异有统计学意义(P<0.05)。结论在早期闭角型青光眼治疗中使用晶状体超声乳化术治疗方法,有助于改善患者视力水平,降低并发症发生率,改善中央前房深度及眼压,疾病临床治疗效果显著。

房角分离手术联合超声乳化人工晶状体植入术对白内障合并闭角型青光眼患者的临床疗效分析

目的:探讨房角分离手术联合超声乳化人工晶状体植入术对白内障合并闭角型青光眼患者的临床疗效。方法:选取2022年1月至2023年1月间于北京康复医院就诊的198例白内障合并闭角型青光眼患者,根据治疗方法的不同将其分为对照组和观察组,每组99例。对照组行白内障超声乳化人工晶状体植入术联合小梁切除术;观察组行超声乳化人工晶状体植入术联合房角分离术。比较两组手术前后的临床相关指标与角膜内皮完整性、手术后3个月临床疗效,以及并发症发生情况。结果:观察组术后3个月临床疗效总有效率为95.96%,较对照组更佳,差异有统计学意义(x^(2)=4.352,P<0.05)。两组治疗后3个月视力水平均有所提高,但组间比较差异无统计学意义(P>0.05);前房深度和前房角度均有所增大,且观察组更大;眼压均有所降低,且观察组低于对照组,差异有统计学意义(t=7.654,P<0.05)。两组治疗后3个月角膜内皮细胞密度均有所减小,而观察组明显大于对照组;角膜内皮细胞平均面积与角膜中心厚度均有所增大,而观察组明显小于对照组,差异有统计学意义(t=25.233、16.608、6.698,P<0.05)。手术治疗后观察组并发症总检率为8.08%,低于对照组的19.19%,差异有统计学意义(x^(2)=5.189,P<0.05)。结论:白内障合并闭角型青光眼患者实施房角分离手术联合超声乳化人工晶体植入术疗效确切,可有效提高患者视力水平,同时也改善了前房深度、前房角度和眼压,更利于维持患者角膜内皮细胞的完整性,且安全性较好。

视觉诱发电位分离格栅模式对原发性开角型青光眼的诊断效能分析

目的评价视觉诱发电位分离格栅模式(Ic-VEP)在原发性开角型青光眼(POAG)诊断中的准确度、灵敏度及特异度。方法选取自2014年11月至2023年2月就诊于中国医科大学附属第四医院眼科的POAG患者52例(104眼)作为POAG组,按照单纯随机抽样原则抽取同时段非青光眼患者40例(80眼)作为对照组。采用柯谛亚视觉电生理检测仪及Humphery自动视野计检测Ic-VEP信噪比和平均偏差等指标。通过绘制受试者操作特征(ROC)曲线,计算曲线下面积(AUC),评估Ic-VEP在POAG中的诊断效能。结果Ic-VEP定性检查的灵敏度为92.3%,特异度为80.0%,准确度为88.0%,AUC为0.873(95%CI:0.793~0.953);IcVEP定量检查的灵敏度为91.3%,特异度为81.3%,准确度为87.0%,AUC为0.863(95%CI:0.804~0.922);Ic-VEP定性、定量检查结果分析显示,早期POAG灵敏度(81.3%,88.4%)均略低于中晚期(82.0%,93.4%),但差异无统计学意义(χ^(2)=0.001,P=0.981;χ^(2)=0.037,P=0.847)。结论Ic-VEP对POAG具有良好的诊断效能,不仅对中晚期POAG具有诊断意义,还可早期发现POAG。

不同分支角度鱼骨井油水运动规律

相对于直井和水平井,鱼骨井具有单井控制储量高、油藏接触面积大等优势,但开发过程中往往需注水来即时补充地层能量。分支井井身结构复杂,现场常采用直井或水平井作为注水井构建不规则的注采井网,而实际生产过程中存在分支井含水上升快、产油量下降快和注水量调配难等问题,亟需开展不同注采方式和不同井型下的油水运动特征研究。利用二维可视化模型、红色染色煤油和黑墨水,通过物理模拟实验研究不同分支角度(30°~90°)鱼骨井一注一采井组在不同注采井型下的油水运动特征,并用数值模拟结果进行验证。结果表明,水平井注水时,油水前缘向分支处偏移更大,油水前缘的推进效果更为均匀;直井注水时,油水前缘推进较为缓慢,但水淹状态时的波及面积更大。直井注水时,分支角度为45°的鱼骨井采出程度(61.10%)最高;水平井注水时,分支角度为30°的鱼骨井采出程度(57.97%)最高,水淹状态时剩余油分布最少。当分支角度小于30°时,水平井的注水效果好;当分支角度大于45°时,直井的注水效果好。对比物理模拟实验和数值模拟实验的油水运动场图和采出程度,结果较为吻合,实验结果与适用油藏特征的匹配性较高。研究结果对实际的油田鱼骨井注采井网部署和参数优化等提供了一定的理论指导和参考依据。

普拉洛芬滴眼液对实施白内障超声乳化抽吸联合房角分离术的原发性闭角型青光眼合并白内障患者预后的影响

目的 观察普拉洛芬滴眼液对实施白内障超声乳化抽吸联合房角分离术的原发性闭角型青光眼合并白内障患者预后的影响。方法 选取2022年1月至2023年12月在合肥市第二人民医院眼科予以针对性治疗的原发性闭角型青光眼伴白内障患者共103例为此次试验的对象,通过随机数字表法分为两组,所有患者均予以白内障超声乳化抽吸联合房角分离术治疗,对照组52例患者术后予以重组牛碱性成纤维细胞生长因子眼用凝胶结合妥布霉素地塞米松滴眼液治疗,观察组51例患者术后加用普拉洛芬滴眼液治疗。比较两组并发症发生情况,手术后1个月的结膜充血和眼压、视功能相关生命质量量表(NEI-VFQ-25)评分和治疗满意度。结果 观察组术后并发症发生率[1.96%(1/51)]低于对照组[15.38%(8/52)],差异有统计学意义(χ^(2)=4.257,P=0.039);观察组术后NEI-VFQ-25得分、眼压和结膜充血评分[分别为(44.23±2.04)分、(15.22±1.89) mm Hg(1 mm Hg≈0.133 kPa)、(1.04±0.27)分]优于对照组[分别为(32.26±2.84)分、(18.45±2.00) mm Hg、(1.42±0.33)分],差异有统计学意义(t=24.526、8.421、6.389,均P<0.05)。在满意度方面,观察组(96.07%,49/51)相较于对照组(84.61%,44/52)更高(χ^(2)=3.859,P<0.05)。结论 原发性闭角型青光眼伴白内障患者实施白内障超声乳化抽吸联合房角分离术术后应用普拉洛芬滴眼液能够降低并发症出现概率,改善日常生活质量以及眼部压力。

原发性闭角型青光眼合并白内障术后视觉质量变化及影响因素

近年来,白内障超声乳化吸除加人工晶状体植入联合房角分离手术逐渐成为治疗原发性闭角型青光眼合并白内障的主要有效手段,然而随着医疗技术不断进步,术后眼压的控制不再是唯一的追求,患者对术后的视觉质量期望越来越高。为了使患者术后拥有更好的屈光状态和更高的视觉质量,需减少因原发性闭角型青光眼所带来的负面影响,个性化选择不同人工晶状体或计算公式等。视觉质量评价指标包括视力、对比敏感度、高阶像差、主观感受等。因此,本文就原发性闭角型青光眼合并白内障患者行白内障超声乳化吸除加人工晶状体植入联合房角分离手术术后屈光漂移、高阶像差、对比敏感度变化及其影响因素以及人工晶状体的选择做出综述。

眼科康复训练对斜视治疗的影响

目的评估眼科康复训练对斜视治疗的影响。方法120例斜视患者,根据治疗方法不同分为实验组和对照组,各60例。实验组在常规治疗的基础上实行眼科康复训练,而对照组则仅接受常规治疗。比较两组患者视觉功能、视轴偏移角度、生活质量。结果实验组患者视觉功能评分为(90.17±2.13)分,而对照组为(78.28±3.81)分,实验组视觉功能明显优于对照组(P<0.05)。实验组的视轴偏移角度为(12.2±3.2)°,对照组为(20.4±3.9)°,实验组视轴偏移角度小于对照组(P<0.05)。实验组的生活质量评分为(93.65±1.99)分,对照组为(84.56±3.17)分,实验组生活质量评分高于对照组(P<0.05)。结论眼科康复训练对斜视治疗具有积极的影响,可提高患者视觉功能,减小视轴偏移角度,改善生活质量,该训练方法可成为治疗斜视患者的有效手段。