AERIAL SURVEY CAMERA TRIALS

During 1985, the opportunity arose to make some test flights with the Wild RC10A and the Zeiss (Oberkochen) RMK A 15/23 with forward motion compensation. This paper outlines the changes incorporated in modern cameras, summarises the Ordnance Survey's photogrammetric tasks, describes the test flights which were achieved and illustrates the results obtained.     

滤光片对航摄仪内方位元素、畸变差的影响

本文论述了滤光片的不平整度和光谱透射特性对航摄仪内方位元素、畸变差的影响,并对航摄仪不戴滤光片与戴滤光片做了对照检定实验,理论分析及实验结果都表明:滤光片对内方位元素、畸变差有较大影响,尤其对色像差较大的航摄仪,其影响更大。文章建议,航摄仪在检定时应加戴航摄时使用的滤光片。     

数字航摄仪在架空送电线路上的应用研究

随着航空摄影的发展,传统航摄仪已明显表现出其局限性,数字航摄仪在影像质量及效率等多方面的优势已愈见明显,其中DMC数字航摄仪已得到广泛应用。文章结合实际生产项目,利用DMC数字航摄仪进行摄影,对摄影比例尺、控制点布控、作业流程、作业方法及加密成图等情况进行了分析和比较。     

ADS 40/80数字航摄仪特点及应用研究

结合目前常见的几种数字航摄仪,以对比的方法简要介绍了ADS 40/80相机的特点,并从ADS航摄影像的用户角度,对ADS相机在应用中涉及的几点关键技术,特别是成图的几何精度问题,进行了阐述和研究.     

EDINBURGH CASTLE ROCK:

Edinburgh Castle is an ancient monument situated on a basalt crag which has steep cliffs falling away on three of its sides. Periodically, remedial measures have to be carried out on these cliffs by engineering geologists in order to stabilise loosened parts of the surface and thus prevent rock falls occurring. The rock structure on the sheer north-facing cliff is currently being studied to determine the extent of work required to ensure its stability. Before such a study could proceed satisfactorily it was necessary to obtain a large scale, contoured survey of the face and this has been achieved by terrestrial photogrammetric methods. Stereoscopic photography was taken with a Wild RC5A wide angle camera pointing horizontally, being specially mounted on its side in the elevated bucket of a Simon hydraulic platform, positioned 17 metres above ground level at a distance of 100 metres from the rock face and at eight successive locations in West Princes Street Gardens. The elevation was plotted with a Zeiss Stereoplanigraph C8 at a scale of 1 : 50 with contours (with respect to a vertical datum) at horizontal intervals of 250 mm.     

轻小型组合宽角低空相机检校技术研究

轻小型组合宽角低空相机由四个非量测的CCD面阵相机组合而成,其内方位元素未知,并且相机畸变差较大.而无人机航空摄影测量作业对CCD相机的光学畸变参数有较高的要求,因为参数的一个像素的误差常常会导致地面几米甚至数十米的误差,因此对组合相机进行高精度检校是无人机航空摄影测量作业的关键步骤.本文采用多片空间后方交会方法在室外...     

由小面阵CCD组合构成宽角航空相机

本文研究由多台小面阵CCD相机构建组合式宽角航空相机的新方法———包括由3台或4台相机组合构建的多相机系统结构,由其分离的各影像转换成等效大影像的数学表达;利用室外和室内近景相机检校场对组合相机系统进行高精度检校的内容、解算方法和检校结果;最后给出了以3相机组合系统装备无人驾驶飞行器(UAV II)进行低空摄影的影像成果。     

倾斜航空影像的城市建筑物三维模型构建研究

针对当前城市建筑物三维模型构建的需要,本文提出一套利用无人飞艇载四组合特宽角相机同时实现高精度空中三角测量和建筑物景观三维建模的技术路线。一方面通过基于四相机重叠影像自动匹配的自检校,达到设备轻小型化条件下的精密等效中心投影构像,用以支持高精度空中三角测量;另一方面,通过自检校的4个方向倾斜的相机,达到一次飞行同时获得四方向建筑物侧面影像的目的,为城市景观的三维表达、精细建模和可视化提供一种新的、快捷的技术方案。     

Analytical methods Of assessing the image quality associated with digital and photographic imaging systems

The introduction of digital cameras for aerial survey photography and use of scanners with processed aerial film present a number of technical questions concerning the way photography is to be acquired in the future. Among the questions to be addressed are the comparative metric properties of images acquired by each system and the associated image quality characteristics. The new digital camera systems will require very careful appraisal, using well-established methods of assessing metric quality already available to survey organisations. The questions concerning image quality are more difficult to answer, as they require very specialised instrumentation if measurements are to be made directly in practice. Over the course of the past several decades a more analytical approach to assessing image quality has emerged, and one that may be used by individuals. The method is particularly effective where information on the micro-image characteristics of products is made available by the manufacturers concerned. An outline is given of some considerations that need to be taken into account when using an analytical approach, with references given for further reading.     

多基线-数字近景摄影测量

根据交会精度与影像匹配自动化的需要,与当今航空数码相机沿航线方向视场角偏小的事实,阐述了大重叠、多基线摄影测量的必要性及其现实意义;重点介绍了利用非量测相机进行多基线的正直、交向摄影方法与数据处理的特点,特别是“多基线交向摄影”,通过多次、多相机对三峡工程地下电站尾水边坡进行拍摄试验,获得了传统非量测相机难以比拟的、非常满意的结果。     

DETERMINATION OF THE WIND VECTOR IN THE LOWER ATMOSPHERE BY STEREOPHOTOGRAMMETRIC SURVEYS OF SMOKE MARKS

A method is described for determining wind vectors in the lower atmosphere from terrestrial stereophotography. The photographs were taken with specially adapted aerial cameras using the normal or parallel averted case with horizontal camera axes. The most favourable photographic registration was obtained on ORWO UT 16 colour reversal film. Photograph co-ordinates and horizontal parallaxes were measured and recorded on punched tape with the Zeiss (Jena) stecometer. Vector components, which were calculated from co-ordinate differences, and a statistical analysis were obtained by using an electronic computer.     

ANALYTICAL ORTHOPHOTOGRAPHY: INSTRUMENT DEVELOPMENT, DESIGN AND APPLICATION

The author reviews the historical background of the analytical orthoprojector and examines the design requirements for this instrument. The construction and performance of the Zeiss (Oberkochen)Z2 orthoprojector are described and an assessment is made of its practical advantages.     

CONSIDERATIONS OF SPECIFICATIONS FOR SMALL FORMAT AERIAL PHOTOGRAPHY

Following the success of the symposium held by the Photogrammetric Society on 31st March, 1987, a second one-day symposium was convened to give further support to the rapidly growing interest in the development of small format photography for aerial survey. This was held at Burlington House, London on 1st November, 1988. Over 70 people attended. Six of the papers are reproduced here, dealing with a range of topics including specifications for and navigation of small format aerial photography, the creation of digital terrain models from 35 mm photography, wildlife surveys in the Arctic and survey photography from model aircraft and tethered balloons.     

数字航空摄影有关技术的分析探讨

随着数字成像技术的发展,数字航空摄影仪必将逐步取代胶片航空摄影仪,在胶片航空摄影中取得的一些航摄设计的技术参数将不再适用于数字航空摄影。本文基于数字航摄的特点,从航摄任务出发,就数字航空摄影时如何较合理的选择相应的数字相机和进行航摄设计等问题进行了初步分析和探讨。     

中小比例尺数字航空摄影测图研究

依据长治DMC数字航空摄影和阜平试验区ADS40数字航空摄影的实验结果,研究分析了框幅式数字航摄仪和推扫式数字航摄仪应用于中小比例尺测图的方式和方法,研究重点侧重于当前数字摄影测量模式下不同外业控制方案对测图精度的影响,并对采用DMC和ADS40数字航摄仪的航空摄影和外业控制的技术设计提出了供参考的建议。     

倾斜影像重叠度计算模型及应用

本文根据倾斜航摄仪中多镜头相机间的位置结构,分析了倾斜影像航向、旁向重叠度与飞行速度、曝光间隔时间、航线间隔等参数之间的关系,在此基础上推导出一种适合任意数量、任意位置相机所拍影像重叠度的计算公式。试验结果表明,该方法提高了倾斜摄影参数设定的准确度,为后期质量保证提供了必要的基础。     

SWDC-4大面阵数码航空相机拼接模型与立体测图精度分析

SWDC-4是由四台非量测相机组成的具有较大幅面的数码航空相机,其主要特点是高程精度高,最高可达1/10000以上。本文介绍了虚拟影像的生成原理以及北京试验区航飞试验所进行的空中三角测量处理结果;从交向摄影的角度理论上详细分析了它的几何与立体测图的精度误差,为该类型相机以后的性能优化,误差分析和实际生产中解决相应问题提供了理论上的重要依据。     

Aerial Photography for Survey Purposes with a High Resolution, Small Format, Digital Camera

This paper discusses the work carried out to obtain stereoscopic "photography" from airborne platforms with a Kodak DCS200 digital camera, as part of an investigation into the suitability of current digital camera technology for use in air survey. Details of the work, from the initial test flight in a Cessna light aircraft through to tests utilizing a Thruster microlight platform, are documented. The paper concludes with a summary of the present shortcomings in obtaining aerial photography for survey purposes with still video technology and discusses the future prospects.     

无人直升机低空数字摄影与影像测量技术

研究和建立了一套无人直升机低空数字摄影与影像测量系统。该系统以无人直升机为飞行平台,以数字相机为传感器,直接获取高分辨率数字影像,具有垂直升降、低空作业、自主飞行等特点。详细介绍了该系统的工作原理,总结了航空摄影关键参数的设计方法,同时,提出了视距网格的飞行模式,增强了系统安全性;利用试验场相机检定的技术,实现了非量测数字相机在摄影测量中的应用。最后介绍了该系统在15 km2大比例尺测绘工程中的应用情况以及综合精度检测结果。     

Simulation of Photometric Conditions by Aerial and Space Photography of the Earth's Surface

A mathematical procedure is presented for simulating the results of aerial and space photography of the Earth's surface as a function of photometric survey conditions. The optical densities of the photographic film are computed with stipulated coefficients of reflection by the Earth's surface, atmospheric optical parameters, illumination conditions, and camera parameters. The described procedure makes it possible to draw conclusions concerning the choice of survey camera for given optical characteristics of the landscape and atmosphere.