一种航摄快门曝光时间均匀性的测试方法

Measurement of exposure uniformity on aerial camera shutter

在航空摄影中,快门曝光时间均匀性对于获得高质量的航空相片十分重要。为评测卷帘式航摄快门曝光时间的均匀性,根据有效曝光时间的分析计算,提出了一种可变缝宽式快门有效曝光时间均匀性的测试方法。在不同帘缝宽度下,依据光电测试法,利用每个测试位置的多次测量结果,运用最小二乘法得到帘缝宽度与有效曝光时间的拟合曲线,与理论曲线比较可衡量出有效曝光时间的不均匀性程度。最后对某卷帘式航摄快门进行了实验测试,测试结果表明有效曝光时间不均匀性为2.8%,满足快门4%的精度要求。经过飞行实验验证,所获得的照片均匀性良好,满足图像判读要求。

Great uniformity of exposure is essential to get high quality aerial photograph.A measurement method of effective exposure time on curtain shutter is raised,which is based on analysis and calculation of effective exposure time on aerial camera shutter.Using multiple metering at each position of different aperture,and according to photoelectric method,a fitting curve of aperture and effective exposure time is obtained applying leas-squares techniques,comparing which to theoretical curve,non-uniformity degree of exposure could be judged.Finally,results of testing a curtain shutter is shown that non-uniformity of exposure is 2.8%,which could meet the required precision of 4%.The photogragh we get from aviation experiment can be satisfied for the aim distinguished.