为了描述重复脉冲激光使扫描型CCD输出视频产生背景条纹的规律,基于这种背景条纹现象的产生机理对理想矩形脉冲激光产生的条纹建立了数学描述模型.通过该模型,可根据相机的时间延迟积分级数、单级积分时间和激光脉冲的脉宽、脉冲重复周期等参量之间的关系来判断背景条纹能否出现并计算背景条纹的尺寸参量,计算精确度为1 pixel.利用重复皮秒脉冲激光和日光灯分别辐照扫描型CCD进行了实验,验证了上述模型计算结果的正确性.在该模型的基础上,结合背景光强与脉冲散射光强的关系,给出了条纹可见度的表达式,并通过实验验证了该表达式所反映出的条纹可见度随着相关参量变化的规律.%In order to obtain the generating law of background fringes in the video of a scanning CCD camera induced by repetitive pulse lasers,a mathematic model describing fringes induced by repetitive square pulse lasers is established.In this model,the relation of camera parameters including stage number of time delay integrations,integration time of one stage as well as laser pulse width and laser repetitive period can be used to estimate whether the fringes appear or not and to calculate what is the dimensions of fringes,in which the precision of calculation is 1 pixel.An experiment is performed by using repetitive picosecond pulse lasers and a fluorescent lamp to irradiate the scanning CCD camera respectively,and the results validate the correction of estimation and calculation based on the model.Finally,combing the intensity relation of background light and scattered laser with the model,the visibility expression of fringes is given,which is also validated in the experiment.
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