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Indo-French team technique improves image capture through fog | India News

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BENGALURU: A team of Indo-French researchers has developed a new imaging technique that can potentially help reveal roadblocks that would otherwise be hidden by fog in rail, sea and road transport and would also help detect beacons. of headlights.
The method can also improve aircraft landing techniques by providing pilots with a good view of airport runway beacons, significantly better than relying solely on reflected radio waves as is the case today.
Researchers from multiple Indian institutions, including the Raman Research Institute (RRI) in Bengaluru and the Isro Space Applications Center (SAC) in Ahmedabad, and Paris-Saclay University, CNRS, France, have developed a new imaging technique that makes images of objects in foggy conditions clearer.
The technique involves modulating the light source and demodulating it at the observer’s end, and further research can demonstrate effectiveness in such real-life conditions. The team is investigating whether you can apply it to mobile sources.
The work was partially funded by the Department of Science and Technology (DST) and the Indo-French Center for the Promotion of Advanced Research.
“While scientists have long tried to use scattering physics and computer algorithms to process the resulting data and improve quality of images, the improvements are not marked in some cases. Computer algorithms require the processing of large volumes of data, which implies extensive storage and significant processing time. The research team has offered a solution to improve image quality without heavy calculations, ”said the DST.
The team modulated the light source and demodulated it at the observer’s end to achieve sharper images. The research has been published in the journal ‘OSA Continuum’, based on demonstrations of the technique by conducting extensive experiments on foggy winter mornings at Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh.
Ten red LED lights were chosen as the light source by varying the current flowing through the LEDs at a rate of approximately 15 cycles per second. The researchers held a camera at a distance of 150 meters from the LEDs that captured images and transmitted them to a computer. The computer algorithms used the knowledge of the modulation frequency to extract the characteristics of the source: “demodulation”.
Image demodulation had to be done at a speed equal to the modulation speed of the light source to obtain a clear image. “We saw a remarkable improvement in image quality. The time it takes for the computer to run the process depends on the size of the image. For a 2160 × 2160 image, the computation time is about 20 milliseconds, ”said BapanDebnath, a PhD researcher at RRI and a co-author of the study.
The team repeated the experiment several times and observed the improvement each time. However, the DST said that one time, when the fog varied in intensity during the observation, they did not register a noticeable improvement in image quality. In this case, there was a strong wind and they observed traces of fog across the scene.
“… The density of the water droplets in the air changed over time, which made this technique less effective. Next, the researchers changed the experimental setup. They made an external material, a piece of cardboard held at a distance of 20 centimeters from the LEDs, to reflect the light towards the camera. The distance between the cardboard and the camera was 75 meters. Modulated light reflected from the cardboard traveled through the fog and was then captured by the camera. They demonstrated how their technique still significantly improved the quality of the resulting image, ”added the DST.



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