Photographic sensor
Also called: Camera · Topic: Remote Sensing, GIS and GNSS · NCERT: Class 11, Ch 6 "Introduction to Remote Sensing"
Meaning
A photographic sensor is a camera. It is an analogue sensor, so it records light directly on film rather than as numbers. It captures the whole scene in one instant of exposure on light-sensitive film. It works only in the optical region, about 0.3 to 0.9 micrometre, which covers visible light and a little near infrared. Its photos can be enlarged without losing detail, which makes them good bases for topographic maps.
Example
An aircraft flying over Delhi with a camera takes aerial photographs on black-and-white or colour infrared film. Mapmakers use such photographs to draw detailed topographic maps of the city's roads and buildings.
Don't confuse with
- Multispectral scanner: this is non-photographic. It builds the image line by line as digital numbers and can record beyond the optical region.
Related concepts
- Sensor
- Multispectral scanner
- Swath
- Whiskbroom scanner
- Instantaneous field of view
- Pushbroom scanner
- Passive and active remote sensing
- Radar
- Synthetic aperture radar
- LiDAR