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Satellites and Sensors

Table of Contents
1. Introduction
2. Sensors
3. Microwaves
4. Image Analysis
5. Applications

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Fundamentals of Remote Sensing

Chapter 2 - Satellites and Sensors
 

2.8 Did You Know?

"...backfield in motion..."

Diagram of a slit camera

There is a photographic parallel to the push-broom scanner. It is based on the "slit camera". This camera does not have a shutter per se, but a slit (A) running in the across-track direction, which exposes film (B) which is being moved continuously (C) past the slit. The speed of motion of the film has to be proportional to the ground speed (D) of the aircraft. Thus the film speed has to be adjusted for the flying circumstances of the moment. The slit width (E) in the along-track direction is also adjustable so as to control exposure time. There are no individual photo 'frames' produced, but a continuous strip of imagery. Stereo slit photography is also possible, using a twin-lens system aimed slightly apart from parallel and each exposing one half of the film width.

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