ISO/CD 9358

Optics and Photonics – Stray light

Scope

This International Standard adopts the veiling glare index (VGI), the glare spread function (GSF), and Point Source Transmission (PST) as measures of the stray light characteristics of optical and electro-optical systems. Laboratory measurement techniques are described in general terms and recommendations are made regarding the performance of the main sub-units of the equipment.
The measurement techniques described in this International Standard are chiefly valid for the visual spectral range. For adjacent spectral ranges, modifications of these techniques will possibly be necessary.
Standard methods of specifying conditions of test and of expressing the results are given and standard test conditions are specified.
This International Standard also gives guidelines for the operation of measuring equipment such that accurate results can be achieved.
Results of measurements made using equipment that does not conform in detail to the configurations described in this International Standard are accepted as valid. The method of measurement shall be substantially similar, i.e. it shall measure the ratio of the irradiance in the image of the black area to the irradiance in a surrounding bright field. In addition, the test results shall be correlated, to the required accuracy, with results obtained using equipment that conforms strictly to this International Standard.