当相干光在粗糙表面散射时,会产生散斑现象。散斑严重影响了图像质量,必须加以抑制。通过散射体振动产生一系列的散斑图样,并在传感器积分时间内加以平均,可以达到抑制散斑的效果。将此方法应用于基于硅基液晶(LCoS)芯片的激光投影系统,并通过一系列实验研究了散斑对比度和散射体运动之间的关系。散斑抑制后,传感器上的散斑对比度从0.49降低到了0.065。实验表明散射体更快更大的振动和更小的单元尺寸都可以降低散斑对比度。

When coherent light scattered from a rough surface,speckle is detected by an intensity detector. Speckle severely affects the image quality and therefore must be suppressed. Speckle suppression can be achieved by averaging a number of speckle configurations produced by vibrating a diffuser. The method is applied in a liquid crystal on silicon (LCoS) based laser projection system,and experiments are performed to study the relation between speckle contrast and diffuser movement. After suppression,speckle contrast on detector is reduced from 0.49 to 0.065. Experimental results indicate that larger amplitude and frequency of diffuser vibration,as well as smaller diffuse phase unit size,can reduce speckle contrast on the detector.