大幅提高视觉密度国家基准测量水平的方法研究

Greatly enhanced visual density measurement level of the national standard densitometer

随着生物医学影像和航天军事测量的发展,对用于光学成像底片和视觉校正的视觉密度的测量范围和不确定度的要求越来越高.以自行设计的光纤半球发射器形成的复合漫射器为特征的新方案将视觉漫透射密度国家基准的光源漫射系数提高到0.945,比欧美国家基准高0.02—0.03.实验得到新基准的测量范围为0—6.0,合成不确定度为0.0015(0<D<4.5)和0.0054(5.0≤D<6.0),相比国际先进水平大幅提高.同时整体结构化的设计可以实现光源组件和探测组件的对调安装,用实验的方法在国际上首次验证了透射测量亥姆霍兹倒易律的有效性.

The national standard densitometer can be used for calibrating photographic film and visual photo. The development of biomedical image and space technology need large measurement range and high uncertainty of visual density. A newly designed equipment using hemispherical emitter with optic fiber can enhance the diffuse coefficient of the light to 0.945 which is higher than the other national standards （0.02-0.03）. Thus the measurement range can be increased to 0-6.0 and the combined uncertainties are 0.0015 （0 〈 D 〈 4.5） and 0.0054 （5.0 ≤〈 D 〈 6.0）. On the other hand, the structure design for the whole equipment can realize the reciprocal fixing between the light module and the detect module. So the validity of Helrnholtz reciprocity for transmittance measurement can be examined and proved on this new equipment.