Researchers developed improved method of imaging objects through fog

Researchers from Raman Research Institute (RRI), Space Applications Centre, Shiv Nadar University in Gautam Buddha Nagar and Université Rennes & Université Paris-Saclay of France have modulated light source and demodulated them at observer’s end to achieve sharper images.

Key Points

  • With this technique, imaging of objects during foggy weather may now be clearer, as this method can improve images captured on foggy days.
  • This technique involves modulation of light source and demodulation at observer’s end.


Researchers have long attempted to use physics of scattering and computer algorithms to process resulting data and improve quality of images. But computer algorithms require processing of large volumes of data increasing storage and processing time.

About the technique

Researchers selected ten red LED lights as source of light. They modulated this source of light by varying current flowing through LEDs at a rate of about 15 cycles per second. A camera was installed at a distance of 150 metres from the LEDs, which captured image and transmitted it to desktop computer. Then, computer algorithms used knowledge of modulation frequency to extract characteristics of the source. This process is dubbed as ‘demodulation’.

Significance of technique

This technique is cost effective as it requires only a few LEDs and an ordinary desktop computer. It can improve landing techniques of aeroplanes by providing pilot with a good view of beacons across the runway. It is better than relying only on reflected radio waves. This method can also reveal obstacles in path which are otherwise hidden by fog in rail, sea, and road transportation. It can help in identifying lighthouse beacons.




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