基于相位匹配的大视场视觉检测系统

针对三维测量大量程和高精度测量问题,提出一种新型双目视觉检测系统.该系统通过向被测物投射间距可变的光栅条纹,将不同曲率的被测表面进行相位编码,由相位匹配得到被测物稠密的立体匹配点云;再由标定出的摄像机内外参数计算出被测物的精确三维坐标.为了解决传感器单元测量区域较小的问题,系统通过步进电机控制传感器移动,获取大型物体的全场三维数据点云;最后利用四元素法,实现大型物体的三维数据拼接.该系统长度测量标准差为36 μm,角度测量与坐标测量机(CMM)测量结果的相对误差0.2％.给出了某V型面三维实测的数据重建结果.对某大型特件(360 mm×300 mm)经过三维拼接正确复现了其三维形貌.该系统对于解决大型构件三维形貌的在线高精度检测问题具有较高工程应用价值.      

宽带雷达信号源自动功率定标与功率控制

介绍一种利用功率检波电平实现对宽带微波雷达信号源的输出功率进行功率定标的方法,以及在不同工作环境下(主要指微波机箱的工作温度)精确实现功率衰减控制的方法。     

自适应卡尔曼滤波在平台射前自标定中的应用

研究了自适应卡尔曼滤波技术在平台射前自标定数据处理中的应用 ,标定采用四位置标定方法 ,对角度传感器输出建立常速度模型。在噪声统计未知或时变的情况下 ,每个位置采用自适应卡尔曼滤波解算出平台各轴的漂移角速率 ,并在此基础上辨识出漂移参数。仿真表明 ,自适应卡尔曼滤波能较好地满足标定精度要求     

傅里叶变换成像光谱仪CCD像元响应非均匀性校正

根据一般成像系统CCD像元响应非均匀性校正的原理与算法,通过对星载可见光干涉成像光谱仪CCD像元响应非均匀性校正的相对辐射定标原理及所获定标数据的深入分析,研究出了一种适于对可见光及红外干涉成像光谱仪系统CCD像元响应非均匀性进行校正的方法,有效解决了干涉成像光谱仪系统探测器阵列非均匀性校正这一工程技术难题,它对今后该方面的科研和技术工作具有积极的指导意义。     

中波红外面阵遥感相机相对辐射定标方法研究

为了促进中波红外面阵遥感相机遥感数据的应用,提出了一种在轨相对辐射定标方法。该方法根据两点定标原理,以中波红外面阵遥感图像数据为基础,利用在轨其他卫星数据获得相机入瞳处辐亮度,计算出非均匀性系数,从而实现在轨相对辐射定标。它为同类红外面阵遥感相机在轨相对辐射定标提供了一种新的思路,同时也可作为星上黑体标的一种校验手段。     

CBERS-O2热红外波段绝对辐射定标及其不确定性分析

文章介绍了2004年CBERS-O2星热红外波段绝对定标工作，结合野外试验情况和数据处理过程深入进行了不确定性因素分析（包括误差分析），并从亮温反演的角度分析定标精度，进而针对如何提高在轨卫星热红外波段绝对辐射定标的精度，进行了探讨。     

Investigation of the Mars Express HRSC color channel calibration

The High Resolution Stereo Camera (HRSC) onboard the Mars Express spacecraft in orbit about Mars has four detector channels dedicated to produce images in four spectral channels. Utilizing these spectrophotometric data requires understanding the instrument radiometric calibration and other photometric properties of the data. We present here some results of our investigation into the HRSC color data characteristics. This covers comparison of HRSC measurements with those of telescopes and the Observatoire pour la Minéralogie, l’Eau, les Glaces et l’Activité (OMEGA) instrument, also on Mars Express. We also investigate the dependence of HRSC Color measurements on solar phase angle and altitude of the Mars surface. These results confirm and extend our earlier findings [McCord, T.B., Adams, J.B., Bellucci, G., Combe, J.-Ph., Hansen, G., Hoffman, H., Jaumann, R., Lumme, K., Neukum, G., Pinet, P., Poulet, F., the HRSC Co-I Team, The Mars Express high Resolution Stereo Camera spectrophotometric data: characteristics and science analysis. J. Geophys. Res. 112, E6, 2007.]. A basic finding from our study is that there are nearly constant offsets between the I/F value derived from the HRSC data and those determined from OMEGA and groundbased telescope measurements, especially in the HRSC red bandpass. These offsets are nearly independent of solar phase angle and Mars surface altitude but are considerably larger for the one comparison at Phobos we were able to make. Several hypotheses could explain these effects: atmospheric scattering, surface photometric effects, shift of the spatial registration or calibration. All these possibilities were investigated.     

Experimental investigation on static/dynamic characteristics of a fast-response pressure sensitive paint

An optical-based technique using Pressure-Sensitive Paint(PSP) is a promising method to measure the distribution of surface pressure on an aerodynamic model. The static and dynamic characteristics of a fast-response PSP that is developed in the Chinese Academy of Sciences(CAS)are analyzed and tested to serve as the basis for experiments on unsteady surface measurement using a fast-response PSP. Two calibration systems used for this study are set up to investigate the temperature dependency, response time, and resolution. A data processing method, used for dynamic data, is analyzed and selected carefully to determine the optimum signal. Results show that the fastresponse PSP can be used normally at temperatures from 25 ℃ to 80 ℃. The effect of temperature on the accuracy of the measurement must be considered when temperatures are beyond the temperature range of 30–40 ℃. The dynamic calibration device with a solenoid valve can achieve a pressure jump within a millisecond order. The resolution is determined by the signal-to-noise ratio of the photo-multiplier tube. Results of the measurement show that the response time of the PSP decreases with a large pressure variation, and the response time is below 0.016 s when the pressure variation is under 40 kPa.     

静基座捷联惯性组合加速度计高阶误差项显著性分析

在标定捷联惯组加速度计时,一般采用多位置试验,但是目前并未对多位置试验所能标定出的误差系数数量和标定结果的有效性进行分析,本文针对这一问题展开了研究.首先,阐述了带有高次误差项的捷联惯组加速度计误差模型.然后,针对一般6位置标定方法无法完成这一模型标定的缺陷,提出了一种18位置标定方法.进行标定后,运用显著性分析方法,对误差模型本身和其中的参数的有效性进行了分析.最后,通过重复进行去除最不显著项、再标定、显著性检验等步骤,获得了试验室条件下所能标定的捷联惯组加速度计组合误差模型.     

GPS-based sea level measurements to help the characterization of land contamination in coastal areas

The Corsica site has been established in 1996 to perform altimeter calibration on TOPEX/Poseidon and then on its successors Jason-1 and Jason-2. The first chosen location was under the #85 ground track that overflight the Senetosa Cape. In 2005, it was decided to develop another location close to Ajaccio, to be able to perform the calibration of Envisat and in a next future of SARAL/AltiKa that will flight over the same ground tracks. Equipped with various instruments (tide gauges, permanent GPS, GPS buoy, weather station…) the Corsica calibration site is able to quantify the altimeter Sea Surface Height bias but also to give an input on the origin of this bias (range, corrections, orbits, …). Due to the size of Corsica (not a tiny island), the altimeter measurement system (range and corrections) can be contaminated by land. The aim of this paper is to evaluate this land contamination by using GPS measurements from a fixed receiver on land and from another receiver onboard a life buoy. Concerning the altimeter land contamination, we have quantify that this effect can reach 8 mm/km and then affects the Sea Surface Height bias values already published in the framework of the Corsica calibration site by 5–8 mm for TOPEX and Jason missions. On the other hand, the radiometer measurements (wet troposphere correction) are also sensitive to land and we have been able to quantify the level of improvement of a dedicated coastal algorithm that reconciles our results with those coming from other calibration sites. Finally, we have also shown that the standard deviation of the GPS buoy sea level measurements is highly correlated (∼87%) with the Significant Wave Height derived from the altimeters and can be used to validate such parameter.