一维相移剪切干涉仪的调制度函数分析

为了分析一维相移剪切干涉仪中调制度的变化规律和影响。研究了一维光栅相移剪切干涉仪的基本原理,推导了干涉光强公式和光强调制度函数。通过将泽尼克单项像差代入到调制度函数因子,分析了泽尼克像差、剪切比对调制度函数的影响,发现测量范围主要受到高级球差和大剪切比限制。设计了一维相移剪切干涉仪的可见光实验装置,在632.8 nm波长分别使用周期为9 mm、18 mm一维光栅测量了一个NA=0.25显微物镜的波像差,实验结果表明:光栅周期为18 mm时可以正确测量,光栅周期为9 mm时,调制度存在反转点,像差超出测量范围,并验证调制度函数分析结果的正确性。

测量调制度传递函数实验的改进系统

介绍了测量调制度传递函数实验的改进，包括光栅的设计制备、机械传动装置的加工改造、实验电路的设计制备、实验软件系统的开发以及微机实控的实现．

理想成像系统调制度传递函数的简要分析

运用简单干涉、衍射原理，辅以作图来分析透镜成像的调制度传递函数和截止频率，物理图象清晰，便于普及光学传递函数这一重要知识，同时很容易得到相干成像的截止频率与照明光入射角有关的这一重要结论。

光栅图像传输法测量海水光学传递函数

根据成像系统光学传递函数的相乘率,用刻有不同空间频率光栅的目标板,研究了在有水体和无水体情况下,光栅图像的传输情况。然后运用mathcad2001软件对采集到的光栅图像进行分析和计算,获得海水的光学传递函数。通过人为地改变水体长度、水中悬浮物质浓度和水体含盐量等,定性地研究了影响海水光学传递函数的因素。该测量方法在激光水下成像、水下目标探测以及对潜激光通信都将具有重要的推广应用价值。

摄影物镜MTF测量中的影响因素研究

从影响摄影物镜MTF测量的各种因素出发,分别以光源颜色、F数、视场角、方位角、以及光强为参数,测量出了不同参数下的MTF值,并绘出了相应的变化曲线。通过分析这些曲线的变化,不仅可以看出MTF随这些参数的变化规律,而且能够形象地得知各参数对MTF变化快慢的影响程度。

用MTF确定三维面形测量系统的投影光栅频率

在基于光栅投影的三维物体面形测量技术中,投影光栅的频率将直接影响着最终的测量精度,在系统参数允许的情况下,尽可能大地光栅频率将带来高的系统测量精度,因此,光栅频率选择是一个关键问题。提出了一种确定投影系统物面光栅频率上限的方法,采用基于图像分析的调制度传递函数测量原理,首先测得系统的调制度传递函数曲线,再由此确定满足系统限制的投影光栅截止频率。将调制度传递函数引入三维面形测量,全面考察系统低通滤波特性,有针对性地指导投影光栅频率的选择。并用实验证明了该方法的有效性。

Influence of Noise on Time Evolution of Intensity Correlation Function

Using the linear approximation method, we have studied how the correlation function C（t） of the laser intensity changes with time in the loss-noise model of the single-mode laser driven by the colored pump noise with signal modulation and the quantum noise with cross-correlation between the real and imaginary parts. We have found that when the pump noise self-correlation time T changes, （i） in the case of r 〈〈 1, the C（t） vs. t curve experiences a changing process from the monotonous descending to monotonous rise, and finally to the appearance of a maximum; （ii） in the case of r 〉〉 1, the curve only exhibits periodically surging with descending envelope. When r 〈〈 i and T does not change, with the increase of the pump noise intensity P, the curve experiences a repeated changing process, that is, from the monotonous descending to the appearance of a maximum, then to monotonous rise, and finally to the appearance of a maximum again. With the increase of the quantum noise intensity O,, the curve experiences a changing process from the monotonous rise to the appearance of a maximum, and finally to the monotonous descending. The increase of the quantum noise with cross-correlation between the real and imaginary parts will lead to the fall of the whole curve, but not affect the form of the time evolution of C（t）.

Stability analysis and stabilization of wireless networked control systems based on deadband control scheduling

The stability analysis and stabilization problems of the wireless networked control systems(WNCSs) with signal transmission deadbands were considered. The deadbands were respectively set up at the sensor to the controller and the controller to the actor sides in the WNCS, which were used to reduce data transmission, furthermore, to decrease the network collision and node energy consumption. Under the consideration of time-varying delays and signal transmission deadbands, the model for the WNCS was presented. A novel Lyapunov functional which took full advantages of the network factors was exploited. Meanwhile, new stability analysis and stabilization conditions for the WNCS were proposed, which described the relationship of the delay bounds, the transmission deadband bounds and the system stability. Two examples were used to demonstrate the effectiveness of the proposed methods. The results show that the proposed approach can guarantee asymptotical stability of the system and reduce the data transmission effectively.