中国科学院光电技术研究所机构知识库
Advanced  
IOE OpenIR  > 光电技术研究所博硕士论文  > 学位论文
题名:
高空CCD数字航空相机高分辨率成像关键技术研究
作者: 钱义先
学位类别: 博士
答辩日期: 2009-06-05
授予单位: 中国科学院光电技术研究所
授予地点: 光电技术研究所
导师: 高晓东
关键词: 航空CCD相机 ; 调制传递函数 ; 振动 ; 无角位移 ; 消热差 ; 变焦系统
其他题名: Critical Technique on High Resolution Imaging for CCD Digital Aerial Camera in High Altitude
学位专业: 测试计量技术及仪器
中文摘要: 航空摄影是获得地面信息的重要手段之一,广泛应用于航空遥感、测量和观测等领域,在地形测绘、土地和森林资源调查、铁路和公路建设、水利和农业规划以及航空摄影领域得到了广泛的应用。 成像质量是航空相机最关键的性能指标,其性能受光学系统形式制约的同时,还受温度、压力、像移、振动、飞行姿态和CCD器件等多种复杂因素的影响。如何消除各种因素对像质的影响,获得高分辨力的图像,就需要深入研究这些因素对航空相机成像质量的影响机理,揭示内在规律。本文基于高空CCD数字航空相机系统,就高空环境下的温度、压力、振动等几个方面对成像质量的影响进行了分析、合理设计,对开发更高品质的航空相机,获取高分辨率的图像具有非常重要的意义。 本文利用了“运动的概率密度函数相当于光学系统的点/线扩散函数”这一概念,采用光学传递函数的理论,得到了动态调制传递函数的一般表达式。采用调制传递函数(MTF)作为评价航空相机光学系统的有效手段,分析振动造成的像移量的大小,研究在CCD航空相机中各振动参数与像移的大小关系。提出图像稳定参数概念,分析了可允许的MTF下降,以及将可允许的MTF下降值转化为有意义、可测量的稳像参数,获得了在曝光时间内可允许的最大的振幅和角振动量的大小,指导稳像设计。 振动是影响动态高分辨率航空成像质量的主要因素,因此航空相机一般都通过隔振系统连接到飞机上以减小振动。建立了高分辨率航空相机的精确三维模型,在此基础上利用有限元分析软件建立了相机及其隔振系统的有限元模型,获得了系统模态和固有频率,合理设计了隔振系统的相关参数,避免共振的出现,用功率谱密度分析方法模拟了复杂的航空振动;分析了不同参数条件下系统的响应频率特性曲线,通过输出曲线和仿真数据检验设计的正确性。 利用空间机构学及平行四边形平动原理,研制了一种新的可抑制角位移的旋转约束机构的减振稳像装置,该装置既能有效抑制因振动产生的角位移,又能有效的隔离高频成分。满足既减小角位移又达到减振要求。根据设计理论给出了设计实例,并利用动力学软件进行测试仿真,仿真曲线验证减振和抑制角位移正确性。 详细地分析了温度、压力对光学结构参数和像质的影响,研究了多种光学系统无热化技术,结合CCD数字航空相机成像系统,提出采用广义变焦系统设计概念来实现可见光折射系统无热化设计,先设计常温下满足成像质量要求的消色差的良好光学系统,然后在工作温度范围内建立多个变焦位置,最后通过合理改变部分材料,满足宽工作温度范围内像质均良好的要求,结果系统在-40℃~+60℃之间成像均保持良好,能满足航空CCD相机高分辨率成像要求。最后对航空相机系统进行了室外分辨率测试实验,结果满足设计指标。
英文摘要: Aerial photography is a key method to acquire ground information, and is widely used in remote sensing, aerial survey and observation, it plays more and more important role in topographical mapping, resource survey, railroad construction, agriculture planning and aerial photograph field. Imaging quality is the most important performance of arial camera.besides the restrict of optical system, image quality are constrainted by many factors such as temperature, pressure, image motion, vibration, flight altitude and CCD device.It is necessary to diminish the impact for requiring high resolution image.Based on the CCD digital aerial camera system, the paper presents the effect of vibration, temperature and pressur on imaging quality, by designed properly, and it is meaningful for developing high quality aerial camera. Base on the theory of optical transfer function, dynamic modulation transfer function was obtained applying the conception of “probability density function of motion is equal to point/line spread function of optical system”.Considering MTF as effective tool for evaluating optical system, image motion was analysed, the relationship between vibration parameters and image motion was studied in some CCD aerial camera. Image stabilization specifications were put forward, allowable MTF degradation was discussed, and converting allowable MTF degradation into those meaningful design parameters for stabilization system was determined, the maximum allowable motion amplitude and angular displacement of camera system during the exposure time was achieved to guide perfect design for stabilization system. Aerial vibration is a key factor effecting image quality of high resolution aviation camera,aerial camera is generally intergrated to aircraft with isolation system. Structural design software solidworks was applied to established accurate 3D model, and based on the 3D model, FEA of camera and its isolation system were built by software Ansys, modal and natural frequency were obtained. Related parameters of isolation system were properly designed to avoid resonance vibration. Complex vibration environment was simulated by power spectral density; response frequency characteristic curves were analyzed with different parameter, the output curve and simulated data shows that the camera and its isolation system were properly designed and can satisfy the demand of high resolution imaging system. Based on the spatial mechanism and translational principle of parallelogram, an irrotational displacement isolator was developed. It can convert angular rotation into linear motion, and can meet the requirements of irrotational displacement and damp. An instance was given based on design requirement. With the help of MSC.ADAMS simulation software, simulated curve proves correct for isolator, and the irrotational displacement mechanism was tested. The effect of temperature and pressure on image quality was represented detailedly, many athermal technique were researched.The conception of general zoom system was proposed to realize athermal design for refractive system in visible range, a good optical system was firstly designed to satisfy image quality in normal temperature, and then multiple zooming positions were established in actual temperature range, the excellent imaging quality was obtained by replacing partial materials properly. The results showed the image quality had a reliable performance with -40℃~+60℃ temperature range, the athermal design can meet high resolution requirement of aerial CCD camera. In the end, resolution test for aerial camera was preceded outdoor, the results satisfied the requirement.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.ioe.ac.cn/handle/181551/346
Appears in Collections:光电技术研究所博硕士论文_学位论文

Files in This Item:
File Name/ File Size Content Type Version Access License
10001_200618015121021钱义先_paper.doc(19389KB)----限制开放View 联系获取全文

Recommended Citation:
钱义先. 高空CCD数字航空相机高分辨率成像关键技术研究[D]. 光电技术研究所. 中国科学院光电技术研究所. 2009.
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[钱义先]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[钱义先]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
Add to CiteULike Add to Connotea Add to Del.icio.us Add to Digg Add to Reddit
文件名: 10001_200618015121021钱义先_paper.doc
格式: Microsoft Word
此文件暂不支持浏览
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Copyright © 2007-2016  中国科学院光电技术研究所 - Feedback
Powered by CSpace