针对传统的激光测距仪测量速度慢、抗干扰能力低以及实时性差等问题，提出了基于并行数字信号处理器 (DSP)的多通道发射和接收的测距系统。在系统中实现了多个调制频率激光的同时发射和同时接收，压缩了测量时间，避免了因目标运动造成的测量数据无法正确融合的问题；根据全相位快速傅里叶变换(FFT)获得的频谱信息，提出了一种将信号幅度谱按泰勒级数展开以求取频率泄露值进行频谱校正的方法。蒙特卡罗(Monte-Carlo)仿真实验证明，该方法较双谱线(Rife)法和能量重心法有较高的精度和良好的稳定性。系统中，AD转换器采样频率为937.5 kHz、进行全相位FFT变换的点数1024时，相位测量精度为0.003°，频率测量精度为0.033 Hz。实验证明，该系统能满足相位法测距系统对实时动态目标测距的需要。

考虑到contourlet变换的多尺度多方向性以及对二维图像具有比小波变换更好的稀疏表示特性,提出了一种基于contourlet变换的图像复原算法。算法采用边界优化的方法,通过类期望最大化算法在contourlet域进行迭代计算,并最终获得惩罚似然函数的最优解。实验结果表明,与传统的基于小波变换的同类图像复原算法相比,基于contourlet变换的复原算法在保持了较低的运算代价的同时,更好地保护了图像的边缘和细节信息,峰值信噪比有0.6 dB-0.8 dB左右的提高。

A new screen-spot imaging method based on optical measurement is proposed, which is applicable to the close-range measurement of aircraft's three-dimensional (3D) attitude parameters. Laser tracker is used to finish the global calibrations of the high-speed cameras and the fixed screens on test site, as well as to establish media-coordinate-frames among various coordinate systems. The laser cooperation object mounted on the aircraft surface projects laser beams on the screens and the high-speed cameras synchronously record the light-spots' position changing with aircraft attitude. The recorded image sequences are used to compute the aircraft attitude parameters. Based on the matrix analysis, the error sources of the measurement accuracy are analyzed, and the maximum relative error of this mathematical model is estimated. The experimental result shows that this method effectively makes the change of aircraft position distinguishable, and the error of this method is no more than 3' while the rotation angles of three axes are within a certain range.

It is difficult to realize real-time measurement of exterior attitude by the traditional systems based on the area image sensor which have conflict between speed and accuracy. The subsystem for three-dimensional (3D) coordinate reconstruction of point target (S3DCRPT) which is composed of three one-dimensional (1D) cameras based on linear charge-coupled device (CCD) can determine the distant light spots’ spatial position. The attitude angle of the measured object is determined by the spatial solution while the coordinate reconstruction is separately carried on by the S3DCRPT with some point cooperation targets (PCTs) on the measured object. A new optical system is designed to solve the interference problem with one-to-one relationship between the PCTs and the S3DCRPT optical subsystems, which improves the measurement accuracy and saves space. The mathematical model of the attitude measurement is established, and partial and global calibrations are realized for the multi-camera attitude measurement system. The test results show the feasibility of the exterior attitude measurement based on linear CCD.

提出了一种估计质心检测不确定度的新方法,首先由像素强度和像素所在位置的图像梯度估计像素强度的不确定度,然后由像素强度不确定度的估计值和像素之间的相关性确定质心检测的不确定度。给出了估计像素强度不确定度的数学模型和估计质心检测不确定度的解析表达式。实验结果表明,用该方法能准确地估计质心检测结果的不确定度。