摘要
介绍了航空侦察相机帘幕式快门的工作原理，分析了胶片感光特性曲线与分辨率的关系。从胶片感光特性曲线确定了使胶片获得高分辨率的最佳曝光量，并由感光材料的性能参数推导出最佳曝光量的表达式。最后，由快门有效曝光时间的表达式计算出能够获得最佳曝光量的快门帘缝宽度的表达式。对EK3412胶片进行了测绘，显影速度分别为10、15、20和25frames／min时的最佳曝光量分别为0．073、0．098、0．116和0．136lx·s。飞行实验验证，所获得的照片分辨率可以提高10％～20％，接近理论分辨率130lpm。将曝光量控制在感光特性曲线直线段的中点．可以显著提高照片的分辨率,满足图像判读要求。
The working principle of curtain type shutter in an aerial camera is introduced and the relationship between sensitive characteristics and resolution for a film is analyzed. Then, expression of the best exposure is deduced by the parameters of photosensitive material. Finally, expression of the slit width is worked out by calculated expression of the exposure time. According to mapping EK3412, the best exposure is 0. 073,0. 098,0. 116 and 0. 136 lx · s ,when the image speed is 10,15,20 and 25 frames/s. After flying experimental verification, the resolution of the film can be increased by 10%-20%,which is closed to the theoretical resolution of 130 lpm. By controlling exposure amount to the mid-point on straight line of the characteristic curve, the resolution of photo be can significantly improved to meet the requirements of image interpretation.
出处
《光学精密工程》
EI
CAS
CSCD
北大核心
2009年第1期196-201,共6页
Optics and Precision Engineering
基金
国家863高技术研究发展计划资助项目(No.2007AA701203)
关键词
航空相机
快门
最佳曝光量
感光特性曲线
帘缝宽度
aerial camera
shutter
most suitable exposure amount
characteristic curve
slit width
