帘幕式快门曝光精度数学建模及计算

Mathematical modeling and calculation on exposure time of curtain-type shutter

为了确定帘幕式快门各尺寸参数与曝光精度的关系，结合帘幕式快门的工作原理及快门的曝光时间表达式建立了曝光精度的数学模型。讨论了影响快门曝光时间精度的主要因素，对曝光时间表达式中的各个参数误差进行了分析，应用误差合成法计算了各个参数误差对曝光时间的影响程度。最后，对现有航空相机中应用的快门进行了精度分析和计算。实验表明：快门的曝光时间精度随着帘缝宽度的增加而提高，现有航空相机快门的曝光时间最低精度为曝光时间的6．4％，高于理论计算精度8．59％。在1／10001／100S，快门的有效曝光时间与帘缝宽度成正比，帘缝宽度对曝光精度的影响是帘缝速度对曝光精度影响的3．6倍。

To determine the relationship between the size parameters and the exposure accuracy of a curtain-type shutter, the expression of exposure time is calculated, and the mathematical model of exposure accuracy is established according to the principle of the curtain-type shutter and its exposure time. Then, the main factors impacting the exposure time accuracy are analysed, and the error for every parameter is calculated with an error synthesized method. Finally, by taking an aerocamera as an example, the exposure accuracy is worked out. The experiment results indicate that the slit width on the curtain-type shutter is proportional to exposure time between 1/1 000-1/100 s, and the exposure