Effect of pedogenesis on the stable isotopic composition of calcretes and n‐alkanes: Implications for palaeoenvironmental reconstruction

In a fluvial system, depending on sub‐aerial exposure, non‐pedogenic pond calcretes can be modified into pedogenic calcretes. The present study attempts to understand the effect of sub‐aerial exposure and pedogenesis on calcretes using carbon and oxygen isotopic composition. For this purpose, two profiles (profile‐A and profile‐B) from the same stratigraphic level in Rayka from the western part of India were selected. The profiles are separated by a distance of 500 m and showed differences in calcrete characteristics. In profile‐A, the calcretes showed pedogenic features (root traces and void filling spar) whereas calcretes in profile‐B showed non‐pedogenic characteristics (fine laminations). However, some of the calcretes in profile‐A exhibited remnants of fine laminations suggesting that initially the calcretes had a non‐pedogenic origin but were modified due to pedogenesis. In profile‐A, the carbon and oxygen isotope values of pedogenic calcrete (δ¹³C_PC and δ¹⁸O_PC) showed more variation compared with non‐pedogenic pond calcretes (δ¹³C_SPC and δ¹⁸O_SPC) in profile‐B. The δ¹³C_PC and δ¹³C_SPC values exhibited a spread of 3·0‰ and 1·3‰, respectively, and δ¹⁸O_PC and δ¹⁸O_SPC values showed a spread of 2·3‰ and 1·3‰, respectively. The differences in the isotopic composition between the two profiles suggest that pedogenesis controlled the isotopic inheritance in calcretes. In addition, the carbon isotopic composition of organic matter (δ¹³C_OM) and n‐alkanes (δ¹³C_n‐alk) that forms the basis of palaeovegetational reconstruction have also been measured to understand the effect of pedogenesis on organic matter in both of the profiles. The average δ¹³C_OM values in profile‐A and profile‐B are ?23·4‰ and ?21·1‰, respectively. The disparity in δ¹³C_OM values is a result of the difference in the sources and preservation of organic matter. However, the δ¹³C_n‐alk values show a similar trend in profile‐A and profile‐B, indicating that sources of n‐alkanes are the same in both of the profiles and δ¹³C_n‐alk values are unaffected by the pedogenic modifications.     

内点最大化与冗余点控制的无人机遥感图像配准

利用小型无人机进行遥感图像配准在自然灾害损害评估、环境监测和目标检测与追踪等领域发挥着至关重要的作用,但小型无人机的图像采集过程容易受风速/风向、复杂地形、电池容量、飞行姿态、飞行高度等自然或人为因素的影响。这些问题通常会导致捕捉到的场景重叠率低与图像非刚性畸变,在特征点提取过程中产生大量冗余点,增加了图像配准的难度。本文提出一种基于特征点的小型无人机图像配准方法,该方法的核心思想是在配准过程中识别冗余点,同时最大化可用内点数量。所识别的冗余点当作控制点,用于控制网格代图像的运动。最后通过最大化内点和合理移动控制点来恢复图像变换。本文使用50对小型无人机图像进行特征匹配和图像配准的实验,其中平均配准精度可达80.38%,并且本文方法在所有的情况下都优于5种当前流行算法。     

重复航空摄影测量方法在乌鲁木齐河流域冰川变化监测中的应用

介绍重复航空摄影测量对比成图方法在监测乌鲁木齐河流域冰川规模和形态要素变化中的应用，以及成图过程中对控制加密和精度等问题的处理。检验表明，航空摄影测量对比成图方法能较准确地量测冰川长度、面积和储量等全形态要素的变化量，可以用于区域冰川变化的监测研究。测量资料表明，１９６４～１９９２年间，乌鲁木齐河流域１５５条冰川的规模均在缩小，冰川末端平均后退率为１２．４％，面积平均缩小率为１３．８％，冰储量减少１５．５％。     

VirtuoZo全数字摄影测量工作站处理数码影像的生产应用

全数字摄影测量主要应用于生产数字地形图及数字地面高程模型（DEM）和数字正射影像图（DOM）。某市及周边地区1：l000地形图航测项目,利用DMC一110摄影仪进行摄影获取的影像数据,使用VirtuoZo数字摄影测量工作站,阐述进行航测内业绘制地形图的全面流程。DMC技术将发挥更大的优势,在数字摄影测量中得到越来越广泛的应用。     

SWDC－4数字航空摄影的质量检查内容及实现手段

针对SWDC－4（ Si wei Digital Camera ）框幅式数字航空摄影的成果质量检查内容,设计了相应的航摄质量、影像质量、文档资料等成果质量检查方法。此方法在日常生产中可快速检查航摄成果质量,对外业航摄进度和内业后期数据处理具有指导意义。     

Practical Experiences with Films, Cameras and Navigation Systems

The first author commenced his experiences with aerial photography in 1945, when he joined the Royal Air Force (RAF). The aerial cameras used at that time were the Williamson F24 and F52, with Ilford HP3 and FP3 panchromatic films. Subsequently the Williamson F95 camera was tested against the USAF Sonne 11 camera. During his final years in the RAF, a variety of film types was employed: colour, monochrome infra-red and false colour infra-red. Additional experience was gained when the author was employed by the International Training Centre (ITC), The Netherlands and he saw the further development of the air camera from the Wild RC8 and Zeiss (Oberkochen) RMK 15/23 to the Wild RC20, Zeiss (Jena) LMK and Zeiss (Oberkochen) RMK TOP. He predicts that the future lies with digital cameras.
The second author started working with aerial photography in the 1950s. Details are given of cameras, visual navigation sights and survey aircraft dating from that period. Overseas operations, carried out mainly by Hunting Surveys and Fairey Surveys, posed particular problems because the majority of the work there was undertaken without the aid of existing maps. The introduction of external navigation systems is described, from the Decca ship navigation system, through the GNS-200 VLF/Omega low frequency radio system to INS, the Inertial Navigation System. The author later joined the ITC, which enabled him to participate in trials of the Computer-controlled Photo Navigation System. Eventually practical experience was gained with differential GPS, particularly in countries in southeast Asia. Aerial photography currently appears to benefit less from financial investment than the photographic, aviation and survey industries. However, the satisfaction of making a significant contribution to major overseas development projects outweighs the frustration of lack of acceptance of plans for the future of the air survey industry.     

虚拟航空摄影测量实验系统的设计与实现

随着网络教学的兴起,虚拟现实技术用于实验教学,成为强化实验室建设、改革实验教学手段的一个重要发展方向。介绍虚拟建模和开发软件,并以我院仿真模拟摄影测量与遥感实验室为原型,采用VRML软件为主,三维建模软件SkecthUP和3Ds Max为辅,阐述系统设计与实现的具体过程,构建虚拟航空摄影测量实验系统。该系统主要包括虚拟地形地貌沙盘(虚拟校园模型和虚拟栅格地形)、虚拟全数字摄影测量工作站模型、虚拟无人机和控制轨道动态模型,以及虚拟实验室场景。具有数字摄影测量工作站动态操作演示、无人飞机航空摄影测量操作演示,以及实验室参观展示等功能。研究成果无实体实验室的时空限制,有利于学生开展自主学习,有效地提高摄影测量实验教学质量,其对于虚拟实验系统的研发具有一定的借鉴意义。     

基于PixelGrid系统的无人机影像空三加密及影像图制作

探讨了基于PixelGrid系统下的无人机影像空三加密方法、工艺流程及正射影像图制作。     

AN ILLUSTRATIVE STUDY ON LOCAL LANDSCAPEAND ITS LONG-TERM CHANGES BASED ON IKONOS AND HISTORICAL AERIAL PHOTO

Nowadays, the research works on landscape at fine scales using high-resolution images are uncommon.This research is based on the analysis of the combination of remote sensing data (1KONOS imagery acquired in 2002 and historical aerial photo taken in 1942). In the paper, the ecotopes in Qiujiadou and Xishao villages in Yixing City of Jiangsu Province in 1942 and 2002 were compared and landscape changes as well as the causes of the considerable changes were analyzed. It was found that the ecotope changes were at greater level in some aspects such as water surface and perennial vegetation coverage etc. This study at fine scale is globally significant for the rural areas, especially for the subsistence agricultural land, which occupies larger percentage in the earth. And it analyzes the structure of landscape based on a new landscape classification system--stratifications method.     

一种手工进行航线设计的算法

航线设计是每次飞行的基础,在航空摄影测量中,它占有重要的地位和作用。航线设计的好坏将直接影响航拍成果的质量,所以在进行每次航拍飞行之前都要对测区内的航线进行设计,以保证航飞的顺利进行。