标准椭圆形封头外表面曲边高度的计算程序

标准椭圆形封头外表面曲边高度的计算程序黄水龙（甘肃省石油化工设计院）关键词椭圆形封头曲边高度计算程序在计算椭圆形封头上接管长度或计算裙座筒体与椭圆形封头对接处的标高时，需要计算椭圆形封头的曲边高度，但椭圆形外表面曲线方程没有表达式，大多数人将椭圆形...     

Shape from Shading Using Probability Functions and Belief Propagation

Shape-from-shading (SFS) aims to reconstruct the three-dimensional shape of an object from a single shaded image. This article proposes an improved framework based on belief propagation for computing SFS. The implementation of the well-known brightness, integrability and smoothness constraints inside this framework is shown. We implement the constraints as probability density functions. For example, the brightness constraint is a two-dimensional probability density function that relates all possible surface gradients at a pixel to their probability given the pixel intensity. A straightforward extension of the framework to photometric stereo is presented, where multiple images of the same scene taken under different lighting conditions are available. The results are promising, especially since the solution is obtained by iteratively applying simple operations on a regular grid of points. The presented framework therefore can be implemented in parallel and is a reasonably likely biological scheme.     

电位器式传感器细分技术在煤气贮罐检测中的应用

煤气贮罐贮气量的检测是一个困扰煤气行业的技术难题。目前用机械式码盘指示贮气量的测量装置仍应用广泛，操作人员用目测法读取指针示值，常会出现漏报和误报数据的情况，将两只电位器式传感器用变速结构连接起来，构成了一种具有细分功能的电位器式传感器。通过建立电位器传感器的数学模型和编制单片机的应用软件，能精确计算煤气的体积。本装置成功地用于干式煤气贮罐贮气量的自动检测系统中，现场运行几年来，工作稳定、性能可靠。     

Extracting Building Height Information based on the Same-name Feature from High-resolution Satellite Image

Based on the idea of the same-name feature,the distance of the same-name straight edge and the main direction parameters of the building are introduced,and the altimetry model of the flat-top straight-edged building is constructed.The feature information extraction technology combining object-oriented and expert knowledge is used to realize the height extraction of the building.Firstly,using the spectral and shape features of the shadow,the detection and localization of the same-name straight edge of the building is carried out from high spatial resolution image.Secondly,based on the detected same-name straight edge vector and the parameter calculation model,the distance of the same-name straight edge parameter is extracted.Finally,based on Building imaging conditions and a new altimetry model to extract building height.The experiment of using the IKONOS and GF-2 image in Beijing area show that the scheme solves the problem that the shadow length of the conventional method is not easy to measure,and the precision is high,reaching the level of the meter,with good human-computer interaction and strong practicality in business operation.     

LiDAR点云支持下地物精细分类的实现方法

在遥感数据分类中,获取精细的地物类别无疑能够传递更加丰富的信息量,进一步加深对遥感数据的理解和解译。在机载LiDAR点云高程数据的支持下,提出并实现了遥感影像上地物精细分类的方法。为保证高精度地同种地物再划分,综合考虑配准、辅助数据源、首次回波、点云密度及影像空间分辨率4种因素,并重点解决了点云密度与影像空间分辨率不匹配的问题,利用决策树显著地提高了影像上建筑物、植被的分类数量,使点云与影像联合分类的优势得到体现,达到了分类精度与地物类别数量相统一的目的。     

一种新的坡位定量描述方法及其与滑坡发生的关系

滑坡发生与地形因子的关系是区域滑坡静态规律研究的重点,但以往的研究多注重考虑其与反映几何形态的基本地形属性因子(几何形态属性因子)之间的关系,如坡度和坡向等。首先提出一种新的基于子流域内相对位置定量描述坡位(相对位置因子)的方法,并以温州地区瓯江流域1990~2001年发生的滑坡为研究对象,使用证据权法对比滑坡发生与两种不同类型地形因子之间的关系。结果表明,相对位置因子与滑坡发生的相关性大于滑坡危险性评价经常使用的几何形态属性因子;并且滑坡大多发生在定量坡位值较低的区域,这些地区处在下游,遭受流水侵蚀的强度更大、频率更高。     

Human responses to augmented virtual scaffolding models

This study investigated the effect of adding real planks, in virtual scaffolding models of elevation, on human performance in a surround-screen virtual reality (SSVR) system. Twenty-four construction workers and 24 inexperienced controls performed walking tasks on real and virtual planks at three virtual heights (0, 6 m, 12 m) and two scaffolding-platform-width conditions (30, 60 cm). Gait patterns, walking instability measurements and cardiovascular reactivity were assessed. The results showed differences in human responses to real vs. virtual planks in walking patterns, instability score and heart-rate inter-beat intervals; it appeared that adding real planks in the SSVR virtual scaffolding model enhanced the quality of SSVR as a human – environment interface research tool. In addition, there were significant differences in performance between construction workers and the control group. The inexperienced participants were more unstable as compared to construction workers. Both groups increased their stride length with repetitions of the task, indicating a possibly confidence- or habit-related learning effect. The practical implications of this study are in the adoption of augmented virtual models of elevated construction environments for injury prevention research, and the development of programme for balance-control training to reduce the risk of falls at elevation before workers enter a construction job.     

Improve the Height Measurement Accuracy in Three-dimensional Imaging Altimeter Using Nadir Interferometric Phase

Roll angle is an important parameter for three-dimensional imaging altimeter to measure Sea Surface Height.The height error due to the roll angle error grows linearly across the swath and a slight error of roll angle will results in a large height error within observation range.So a very accurate knowledge of the roll angle error is required.Nadir interferometric phase has a strong correlation with the roll angle,so using the nadir interferometric phase from the interference image can get roll angle more accurately than instrument measurements.It’s possible to meet the centimeter-level accuracy after correcting the roll angle error.Simulation measurement and elevation reconstruction based on the geometric relationship were performed,and the research of correction the roll angle error by nadir interferometric phase was carried out.Both theoretical calculation and numerical simulation show that the measurement accuracy of roll angle can be as high as 0.03 arcsecond when the accuracy of nadir interferometric phase is 10-3rad.In this case,the height measurement accuracy have been averaged across a swath between 10 and 60 km of nadir will decrease to 0.48 cm which is 6.02 cm when the roll accuracy is 0.36 arcsecond.It means that the nadir interferometric phase method can effectively correct the roll error of three-dimensional imaging altimeter.     

基于某低空飞艇压力高度及载荷能力的研究

由于大气压力、温度随着海拔高度的变化而变化.在飞艇升降过程中,艇囊中的浮升气体(氦气)随着外界大气压力、温度的变化产生压缩或膨胀,使飞艇净静升力发生变化,从而影响了飞艇的载荷能力和能够达到的海拔高度.为了在标准大气(International Standard Atmosphere)和非标准大气(Off-Standard Atmosphere)条件下,研究了飞艇压力高度随充氦体积变化规律和载荷能力随高度变化的规律,给出了充氦体积占飞艇总气囊体积比例、压力高度、净静升力和有效载荷之间的变化关系,并结合某低空试验飞艇进行了仿真计算和分析,为飞艇的总体设计和实际使用提供了理论基础.     

红外云图晴空区导风风矢高度指定方案与检验

在静止卫星红外云图上,用实际大气廓线的响应权重取代标准大气的响应权重,对利用时间序列差分法反演出的晴空区风矢,进行高度重新指定。然后对台风个例高度重新指定前、后的晴空区风矢进行了误差统计检验和分析,最后利用三维中尺度同化系统WRF\|3DVAR进行了敏感性试验。结果表明:利用实际大气廓线的权重响应进行高度指定优于标准热带大气廓线,晴空风矢高度主要分布在600~900 hPa之间;经高度重新指定后各高度层上的晴空区风矢的均方根差和标准差明显减小,风速偏差集中。同化经过高度重新指定的晴空区风矢能够减小台风路径预报误差。因此,对晴空区风矢进行高度重新指定能够改善晴空风矢产品的质量。