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平场校正对获得高质量的遥感图像起着非常关键的作用。针对利用商业相机开发的传感器需要进行平场校正的问题,提出对Agriculture Camera(AgCam)传感器的平场校正方法。应用AgCam的定标实验数据分别得到传感器CCD阵列的暗电流(Dark Current),渐晕效应(Vegnitting Effect)和光电响应(Quantum Efficiency)的校正系数。AgCam的定标实验数据和实际拍摄图像处理结果表明,该方法能够有效地对AgCam的平场效应进行校正。 相似文献
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简述了循环水槽的结构和技术指标,论述了循环水槽的技术指标能满足检定RCM4安德第流计流速传感器的技术要求。检定资料的采集和检定数据的处理方法,最后对使用中的RCM4海流计流速传感器检定和循环水槽的性能改造提出了几点建议。 相似文献
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我国“海洋1”号卫星(HY-1)CCD图像数据定量化条带消除研究 总被引:5,自引:0,他引:5
条带(striping)对于大量的航天和航空传感器来说是一种普遍存在的现象,任何使用多个探测器进行数据获取的遥感器图像数据中均存在条带.目前消除条带的算法主要是针对光机扫描仪,对于CCD相机工作做得比较少.针对HY-1CCD线阵推扫式多光谱相机的特点,以及发射前辐射定标的结果,对遥感器图像数据中的条带问题进行了预研,提出了一种定量化的消条带算法.该方法根据卫星数据特性求出各探测器间的均衡化曲线以反映探测器之间的差异,并据此来消除条带.实验结果表明该方法能够有效解决CCD相机的条带问题,而且可以保持数据原有的物理意义,并可与在轨辐射校正衔接,保证发射前后定标算法的一致性. 相似文献
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应用一种基于遗传算法的二类水体水色反演算法,评估了HY-1A CCD反演水体组分浓度的能力.算法采用了三组分(叶绿素、悬浮物质和黄色物质)海水光学模型作为前向模型,以二进制编码遗传算法作为优化方法.通过多次反演试验,讨论了遗传算法参数对反演结果的影响;通过构造不同目标函数,讨论了目标函数对反演结果的影响;通过波段平均前后的数据模拟反演,分析了HY-1A CCD的波段平均对水色反演的影响;分析了该水色优化反演算法的浓度范围适用性;最后分析了该算法对输入数据误差的敏感性.模拟反演表明,HY-1A CCD可以用于进行二类水体水色反演,特别是在悬浮物质反演方面,该传感器优势明显. 相似文献
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基于交叉非对称的czerny-Turner结构, 研制了一种微型光纤光谱仪, 采用光栅分光、线阵CCD探测光, 基于复杂可编程逻辑器件及PC104设计CCD数据采集电路, 采样结果通过PC104总线上传至PC104工控机, 光谱仪及数据采集电路集成为一光谱仪模块, 约为96mm(宽)×104mm(长)×18mm(高), 该模块与PC104工控机之间通过PC104总线以“针”和“孔”形式层叠连接, 在具有体积小、功耗低、采样速度快等优点的同时还具有极好的抗震性, 非常适合于野外恶劣工作环境下的在线使用。将其应用于海水中铁等痕量元素及营养盐在线检测仪, 试验结果良好。 相似文献
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利用纵振换能器的纵向振动与换能器前盖板的弯曲振动相耦合原理,采用纵振换能器与声反射器配合,研制出一种适应在复杂海洋声信道进行高速率传输,具有低频,宽带,大功率等优点的水声换能器。 相似文献
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Satoshi Someya Shigeru Bando Yongchen Song Baixin Chen Masahiro Nishio 《Journal of Oceanography》2004,60(4):789-795
We established a precise DeLIF (Dual Emission Laser Light Fluorescence) system for the instant measurement of the pH field
in laboratory experiments. This method is very important in studies of the biological impacts of CO2 sequestration, i.e., effects of pH on organisms. The technique is demonstrated by applying it to the pH measurement around
a liquid CO2 droplet, which has a large gradient of CO2 concentration near its interface, the concentration value on the boundary being known as the solubility of CO2. In the Laser Induced Fluorescence (LIF) method using quinine and an ultraviolet laser light source, the relatively unstable
pulse of the laser source decreased the measurement reliability. We therefore investigated many kinds of fluorescent dye and
demonstrated the DeLIF measurement, identifying a process for cancelling fluctuations of laser light intensity. Quinine and
sulforhodamine were used as fluorescence dyes. The molar absorption coefficient and emission intensity of quinine depend on
the pH of aqueous solutions, while those of sulforhodamine are not as much affected by pH. The ratio of these fluorescence
intensities represents pH at each point of the image. As a result, the pH field was successfully measured with an uncertainty
of only approximately ±0.005, for 3.0 < pH.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Long-range underwater acoustic systems, such as those used in ocean acoustic tomography, require low-frequency signals covering a broad frequency band. To meet this requirement, a novel design based on a tunable narrow-band high-efficiency sound projector has been used. The projector transmits a frequency sweep signal by mechanically tuning a resonator tube (or organ pipe) to match the frequency and phase of a reference signal. The resonator tube projector consists of a symmetrical pressure-balanced Tonpilz driver placed between two coaxially mounted tubes. The Tonpilz acoustic driver is composed of two pistons separated by preloaded ceramic stacks. The resonant tube is a simple, efficient, narrow-band, medium-output projector that operates at any ocean depth. Both projector tubes have slots (or vents) which are progressively covered or uncovered by sliding coaxial tubular sleeves. The frequency varies with the sleeve position. A computer-controlled electromechanical actuator moves the cylindrical sleeves along the tubes, keeping the projector in resonance at the instantaneous frequency of a swept frequency signal. The actuator smoothly tunes the resonator tube frequency in a bandwidth of 200 to 300 Hz during a 135-s transmission. A computer synthesizes the linear frequency-modulated signal; compares the phase between transmitted and reference signals; and, using a phase-lock loop (PLL) system, keeps the resonator tube frequency in resonance with the driver frequency. The estimated PLL precision is better than 3/spl deg/ phase error. The system was analyzed by means of finite element analysis and electrical equivalent circuit simulation. The projector prototype was first tested at the Woods Hole Oceanographic Institution (WHOI) dock in Woods Hole, MA and later in the Pacific Ocean during a voyage of the R/V "Point Sur" in November 2001. 相似文献
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海洋浮游植物光合作用固碳在全球碳循环中扮演着极为重要的角色, 获取不同光衰减对应的海水深度, 对于采集水样用于海洋初级生产力的研究具有重要意义。本研究于国际上首次开发了无缆便携式海洋透光率仪, 特殊的光学结构设计和光谱滤光技术使得光谱响应在波段400~700nm范围内超过了同类海洋传感器, 特定光衰减下对应的深度误差小于0.5m。将本设备应用于南海中尺度涡旋初级生产力的研究中, 在采样率和自动化方面验证了仪器的便携性; 通过对涡旋中初级生产力的空间分布规律进行分析, 检验了仪器数据结果的可靠性。海洋透光率仪在价格、准确性、可靠度和操作的便携性上具有不可比拟的优势, 将在未来海洋生态环境的研究中发挥重要作用。 相似文献
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In this paper, we experimentally perform the measurement of the backscattered light intensity from the underwater targets with different size. We develop a simple system, which can easily measure the intensity of the backscattered light, after the laser is scattered at the target underwater. We find that, the signal period is related to the particle size, and the stability of the intensity (standard deviation) varies linearly with changing the particle size. After the calibration, our system can be used to precisely determine the particle size of arbitrary targets. Our method could open a new opportunity for the future underwater detection using femtosecond pulse laser. 相似文献
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叶绿素浓度是衡量海洋浮游植物丰度的重要指标,快速准确地测定海水中的叶绿素含量,对于业务化监测和科学研究都具有重要的现实意义。基于活体荧光法的叶绿素传感器操作简便,可长期原位在线监测,能轻易获取大量实测数据,是当前海水叶绿素高精度测量手段的主要发展趋势。由于在海上应用时受到多种环境因素的影响,叶绿素传感器数据与实验室萃取法数值之间存在较大偏差。作者综述了科学界在浊度、光照、温度、盐度等海洋环境因素及藻类生理因素对叶绿素传感器测量的影响规律、影响机理和数据校正方法的研究进展,并对活体荧光法叶绿素传感器海上应用数据质量控制方法的研究思路进行了展望。 相似文献
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研究海水温盐结构的反射地震方法 总被引:2,自引:1,他引:1
在物理海洋学的研究中,利用CTD(Conductivity, Temperature and Depth sensors)测量方法研究海水温盐结构存在着获取数据时间长、数据横向精度低的缺点,而利用反射地震记录可以获得剖面上连续的水体温盐结构,弥补了传统方法的不足.反射地震方法研究海水温盐结构是个新的交叉学科方法,称为"地震海洋学".由于海水水体的物性变化比地层物性变化小得多,造成海水水体的反射地震资料信噪比很低,各类干扰强烈,因而海水水体的反射地震资料处理也和常规地震资料处理方法有所不同.它处理的重点是振幅补偿,叠前去噪以及叠后处理.笔者通过对"十五"973项目在南海东北部采集的一条高分辨率多道反射地震测线的海水水体部分的地震数据进行处理,压制了强线性干扰波,获得了水体反射图像.地震叠加速度分析获取的3个CDP (Common Depth Point)的垂向速度从1540 m·s-1单调减小到1478 m·s-1,与CTD测量得到的速度变化趋势一致. 相似文献