The Measurement of Contrast and Range in Air to Ground Viewing

In the previous paper of this series it has been shown that Photographic Detectors can be used very effectively to measure and study the atmospheric attenuation for air to ground viewing paths. The present paper considers the more general measurement of the contrast of objects on the ground against their immediate background. The problems of range measurement when studying range dependent brightness parameters in the air to ground viewing situation are also considered. It is shown that, whilst considerable errors must be accepted when using the simplest form of instrumentation, useful results can be obtained with no other equipment than a good quality kine camera mounted in an aircraft.