数字光处理投影系统成像质量测量方法

Imaging quality measurement of digital light processing projection system

介绍了数字光处理(DLP)投影系统的工作原理,提出了基于光学调制传递函数(MTF)的成像质量测量方法.利用绿场传感信号探测数字微镜器件(DMD)的快速翻转,并实现数字微镜器件翻转、电荷耦合器件(CCD)曝光时间和图像采集三者之间的严格同步.对数字微镜器件图像在x、y两个方向上进行快速傅里叶频谱分析,根据其二阶调制传递函数幅值提出了3个评价指标,分别反映数字光处理投影系统中像质的最差值、平均值以及离散度.实验结果表明,该方法的设计思路合理可行,成像质量测试系统具有良好的精度和稳定度,可以为数字光处理投影机的质量控制提供有效的评估手段.

A method was proposed to evaluate the imaging quality of digital light processing （DLP） projection system based on optical modulation transfer function （MTF）. The proposed method detected the fast switching timing of digital micromirror device （DMD） from green-field signal, and achieved the synchronization of DMD switching, exposure times of 9 charge coupled device （CCD） cameras, and image capturing. The quality of the captured DMD image was evaluated using fast Fourier transforms along x and y directions. Three objective indexes were proposed based on the amplitudes of second-order MTFs to measure the minimum, average and deviation of imaging quality, respectively. Experimental results indicate that the proposed method is accurate and stable, and can be applied for imaging quality measurement in DLP quality control.