Estimation of Fractional Vegetation Cover Based on Digital Camera Survey Data and a Remote Sensing Model

The objective of this paper is to improve the monitoring speed and precision of fractional vegetation cover (fc). It mainly focuses on fc estimation when fcmax and fcmin are not approximately equal to 100% and 0%, respectively due to using remote sensing image with medium or low spatial resolution. Meanwhile, we present a new method of fc estimation based on a random set of fc maximum and minimum values from digital camera (DC) survey data and a di- midiate pixel model. The results show that this is a convenient, efficient and accurate method for fc monitoring, with the maximum error -0.172 and correlation coefficient of 0.974 between DC survey data and the estimated value of the remote sensing model. The remaining DC survey data can be used as verification data for the precision of the fc estimation. In general, the estimation of fc based on DC survey data and a remote sensing model is a brand-new development trend and deserves further extensive utilization.

Evaluation of the Anterior Chamber Angle Structures in Perinatal Infants Using a Wide-Field Digital Fundus Camera

Objective This study aimed to evaluate the ability of a digital fundus camera to observe the development of the anterior chamber angle(ACA)in premature infants.Methods Forty-eight eyes of preterm infants(n=48)were examined by a digital fundus camera to observe the development of the ACA.ACA grading was performed based on the visualization of the anterior chamber structures according to the Scheie Angle Depth Evaluating System.Results ACA images from all 48 infants were successfully acquired using RetCam3.The corrected gestational age ranged from 30 weeks to 49 weeks,which covered the period from 2 months preterm to>2 months post-term.As the corrected gestational age increased,the corrected gestational age grading was significantly decreased.The mean corrected gestational ages of the infants corresponding to the ACA classification from grade IV to grade 0 were 32.75±1.89,37.20±1.30,39.75±2.38,40.56±2.24,and 44.23±2.14 weeks,respectively,which were all significantly different(P<0.05).The regression analysis showed a linear correlation between the grading of the ACA and the corrected gestational age(R2=0.724,P=0.0001).Conclusion The ACA of a full-term newborn can be fully detected and evaluated by a digital fundus camera.For premature infants,part of the ACA is not visible physiologically;however,it should not be misdiagnosed as angle closure or a narrow angle.

Spectral Measurement of Atmospheric Pressure Plasma by Means of Digital Camera

A digital camera measuring system has been used successfully to measure the space fluctuation behaviors of Induced Dielectric Barrier Discharge (IDBD) plasma at atmospheric pres- sure. The experimental results showed that: (1) The uniformity of electron temperature in space depends on discharge condition and structure of web electrode. For a certain web electrode the higher the discharge voltage is, the more uniform distribution of electron temperature in space will be. For a certain discharge the finer and denser the holes on web electrode are, the more uniform distribution of electron temperature in space will be (2). Digital camera is an available equipment to measure some behaviors of the plasma working at atmospheric pressure.

Multi-digital Still Cameras with CCD

Digital still camera is a completely typical tool for capturing the digital images. With the development of IC technology and optimization-algorithm, the performance of digital still cameras(DSCs) will be more and more powerful in the world. But can we obtain the more and better info using the combined information from the multi-digital still camera? The answer is yes by some experiments. By using multi-DSC at different angles, the various 3-D informations of the object are obtained.

Enhancement of Frame-rate Using Digital Camera

Frame rate is corresponding to the temporal resolution and the number of the pixels of the picture is corresponding to the spatial resolution. They are both very important for the researchers. The ideal image analysis and processing system should have high spatiotemporal characteristics, which is much expensive in practical use. A new method to enhance dynamic frame rate using multi-digital camera(DC) is proposed and the result shows that it could increase the frame rate effectively and decreases the cost in practical use.

Positioning of Screw Holes Group Based on Digital Camera and Digital Control Drilling

Positioning of screw holes is an important production procedure for steel construction connecting with bolts. In this paper, a new production method is presented, in which the digital camera is used for taking pictures of screw holes and other techniques are advanced. This paper also indicates that the pixels of CCD chip in photogrammetry should be chosen as all geometric units in an image, such as interior elements and all kinds of distortions. The measure can also simplify the camera calibration for determining the size of non-square pixel.

1分钟,给你的相片做美容——Digital Camera Tools合家欢

用数码相机拍得的相片,在保存和网络传输方面有不容置疑的优越性,因此越来越多的人开始使用数码相机。但是我们不得不承认,它在成像质量方面还不能完全替代传统的相机。在你的数码像册里有没有一些太亮、太暗或者有杂点的问题照片呢?不要以为它们没救了哦,看了今天介绍的方法你就会知道,其实要给它们做美容一点都不难,只要一分钟就可以让你的相片白净又明亮! 咱们要用的这一系列美容工具叫做:Digital camera Tools(本文介绍的软件都可在http://www.mediachance.com/digicam/下载),这些简单又实用的小工具基本上可以解决数码相片中存在的大部分常见问题,比如:偏色、亮度不正常、有杂点等,对传统相片中的类似问题也有一定的作用。每一种工具都有它的适用范围,如果你的照片不在其适用范围之内,或者原本就拍得不错的话,那你可能就看不到太大的差别哦!

Digital Camera影像视觉牵手搜狐举办中国首届无人机摄影大赛获奖作品选登

ANDERS ANDERSSON_海外组一等奖我想一直想用无人机拍这样的自拍照片,于是邀请了我的邻居朋友Tobias在瑞典Ljungby的一个社区摆出这样的姿势。我们在泳池开放时间提前一个小时到达,大概半个小时后完成了拍摄。我也很想在泳池里人多的时候拍,但是考虑到会有一定的危险就没有实行。"

A Model for Estimating Total Forest Coverage with Ground-Based Digital Photography

Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.

Using UAVs for detection of trees from digital surface models

A difficult problem in forestry is tree inventory.In this study, a GoProHero attached to a small unmanned aerial vehicle was used to capture images of a small area covered by pinus pinea trees. Then, a digital surface model was generated with image matching. The elevation model representing the terrain surface, a ‘digital terrain model’,was extracted from the digital surface model using morphological filtering. Individual trees were extracted by analyzing elevation flow on the digital elevation model because the elevation reached the highest value on the tree peaks compared to the neighborhood elevation pixels. The quality of the results was assessed by comparison with reference data for correctness of the estimated number of trees. The tree heights were calculated and evaluated with ground truth dataset. The results showed 80% correctness and 90% completeness.

Diameter Measurements of the Upper Parts of Trees Using an Ultra-Telephoto Digital Photography System

We develop a new technique to measure the exact upper diameters of trees that is comparatively simple and inexpensive. We can measure the diameters of entire tree trunks efficiently and with high precision. The system uses a digital camera with a ~15 - 30× telephoto lens to take a photograph that can be used for measuring the diameter of the upper part of a comparatively slender tree trunk. Since this method requires a measuring distance and the height of the target point in the image, a range finder capable of measuring angles was combined with the main digiscoping system. A range finder sensor uses a laser and makes a 360 degree angle of observation possible. The diameter of a target position of the objective tree can be obtained by measuring the digital image using image editing software and calculations from spreadsheet software. We focus on the Japanese cedar species in the southwestern part of Japan. Photographic measurements were obtained prior to thinning. The estimates that we obtained largely agree with the true measurements of all trees. With regard to the estimated accuracy of all measured trees, the maximum error ratio was 7.0% (1.45 cm), with a ~2% - 4% error for most of the estimated results. Although the absolute value of the estimation error was 1.87 cm (5.3%) at the maximum (9.87 m in height and 35.5 cm in diameter), an estimation accuracy of <1 cm was reproduced in almost all measurements except for the extreme hypertrophy portion by butt swelling.

基于DIC的露天矿山微差爆破模型试验及数值模拟

随着电子雷管在露天矿山台阶爆破中的全面使用,微差爆破技术得到进一步发展,如何通过调整孔间延时提高炮孔之间相互作用力,成为矿山爆破技术的研究重点。基于混凝土模型模拟露天矿山微差爆破,建立高速摄影技术与数字图像相关(DIC)试验系统,基于全场微应变、高速摄影技术和数值模拟对不同孔间延时条件下的炮孔间裂纹发展过程进行了研究。结果表明:爆炸载荷下模型表面裂纹附近的应变持续时间约为3 ms,孔间延时为3 ms时下一个炮孔起爆能够提高炮孔之间的相互作用力;通过数值模拟展示了测点的压力分布特征,在孔间延时为3 ms时测点压力最大,验证了模型试验的准确性;利用MATLAB对数值模拟结果分析发现,孔间延时为3 ms时其破碎程度最佳,与模型试验结果具有较好的一致性;使用高速摄影技术结合DIC方法为研究炮孔之间的相互作用力及裂纹扩展提供了新思路。

高新技术格式数字电影摄影机性能测试及研究

为对高新技术电影格式进行创新探索和技术革新,中国电影行业提出自有数字电影高新技术格式标准,确保中国电影在画质清晰度、色彩表现力、视觉效果等方面能够达到甚至超越国际标准,为中国电影艺术的视觉表达开辟了新的维度,增强观众的沉浸感和情感共鸣。基于此,中影电影数字制作基地有限公司开展了高新技术格式数字摄影机选型测试工作,本次测试围绕不同画幅数字摄影机在拍摄高新技术格式时的画面分辨率、宽容度、亮暗部色彩还原与噪波表现,以及不同机型在完整拍摄流程上的表现进行了测试。本文为测试的前后期工作做了较为详尽的总结,同时也为中国自有数字电影高新技术格式标准在实拍器材部分标准的确定方面进行先期实践与科研。

基于DSP+FPGA的Camera Link接口相机的图像处理平台设计

以FPGA和DSP为中心,设计实现了Camera Link接口相机的数字图像数据的VGA和PAL双制显示,解决了数字图像数据由FPGA与DSP之间高速、大数据量的实时传输。DSP对数据进行实时处理后,经千兆网络向控制计算机终端传输图像数据,解决了相机数据传输距离的限制,拓展了高速网络相机的应用范围。

基于无人机航拍的苎麻倒伏信息解译研究

茎杆倒伏是苎麻三麻培育中最常见的灾害,传统的监测方法具有耗时耗力、不及时等局限性。提出了一种基于无人机航拍获取苎麻倒伏信息的方法,首先利用Pix4D Mapper软件生成苎麻的冠层正射影像和数字表面模型(digital surface model,DSM),基于正射影像提取苎麻光谱、纹理及形状特征,基于DSM提取苎麻株高指标,最后结合3种机器学习算法构建正常/倒伏苎麻分类模型。结果表明,基于DSM提取的株高信息可以有效代替大田实测株高,模型R2为0.899。倒伏和正常苎麻在光谱、纹理、形状及株高特征上具有差异。在3种机器学习算法中,支持向量机和决策树模型的性能最好,准确率达到99%,能够高效地识别苎麻倒伏地块。以上研究结果为准确、快速评估作物倒伏情况提供了技术支撑。

基于异步FIFO的Camera Link数字图像光纤传输技术

为满足数字图像的远距离传输需求,设计用于传输Camera Link接口数字图像的光纤通讯系统。系统分为发送和接收两个部分,分别负责Camera Link数字图像到光信号的转化以及相应的逆变换过程。采用Cyclone I EP1C12 FPGA作为发送和接收板卡的逻辑控制核心。在发送板卡的FPGA内设计逻辑控制模块,操纵两个异步FIFO(先入先出队列),将接收到的数字图像缓存,用本地时钟读取后再进行串行化转换。在不改变数字图像时序关系的前提下,用本地时钟替换原有的像素时钟,消除像素时钟不稳定性对后续传输影响。实验表明,利用该技术可以有效提升光纤传输系统的适应性、稳定性,改善、消除由像素时钟抖动造成的传输图像抖动现象。

基于单高速相机3D-DIC的涡轮叶片全场振动测量

采用成本较低、结构紧凑且使用便捷的单高速相机三维数字图像相关方法(single-camera high-speed three-dimensional digital image correlation,简称SCHS 3D-DIC)对涡轮叶片的振动特性进行试验研究。首先,介绍了测量装置和原理,以悬臂铝板为对象开展验证试验,结果证明了该测量系统的准确性与有效性;其次,开展了叶片的全场振动特性测量,得到了其三维形貌、模态特性、全场位移与应变分布,获得了叶片在振动载荷作用下的高应变区域位置及应变分布特点。研究表明,SCHS 3D-DIC方法相比常规双高速相机3D-DIC方法具有更高的视场利用率,适合于细长型的涡轮叶片的振动测量试验。

一种GNSS与相机集成的实时水边界测绘新方法

针对水边界测绘现有方法施测困难等问题,提出一种免像控、免惯导支持的实时水边界船基摄影测量方法。该方法通过GNSS罗经、数码相机、计算机组网与通信端口编程,实现数据的全自动采集;采用自检校光束法实现传感器的标定与数据配准;构建自由网光束法空三平差模型,引入水位和外方位线元素最小范数条件约束,实现三维水边线的高精度提取。长江实时水边界测绘典型实验结果表明,本文方法切实可行、精度可靠,中误差优于0.2m,可有效消除作业人员安全风险,降低劳动强度,实现水下地形与水边界一体化测绘,且具有成本低、续航持久等显著优势。