Researchers find an improved method of imaging objects through fog

Researchers find an improved method of imaging objects through fog

Imaging of objects in foggy weather conditions may now be more clearer. Researchers have discovered a method that may enhance the images captured on such days. The technique involves modulating the light source and demodulating them in the viewer's end.

Scientists have long attempted to utilize the physics of scattering and computer algorithms to process the resulting data and enhance the quality of images.  Whereas the improvements aren't stark sometimes, computer algorithms require processing large quantities of information, involving considerable storage and substantial processing period.

Research by a team has provided a solution for enhancing the image quality without significant computations. The team in the Raman Research Institute (RRI), Bengaluru, an autonomous institute of the Department of Science and Technology; Space Applications Centre, Indian Space Research Organisation, Ahmedabad; Shiv Nadar University, Gautam Buddha Nagar; and Université Rennes and Université Paris-Saclay, CNRS, France, modulated the lighting source and demodulated them in the viewer's end to Attain sharper images. The study was published in the journal 'OSA Continuum'. 

The researchers have shown that the technique by conducting comprehensive experiments on foggy winter evenings in Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh.  They picked ten red LED lights because the origin of lighting. Then, they modulated this origin of light by changing the current flowing through the LEDs in a rate of approximately 15 cycles per second.

The researchers maintained a camera in a distance of 150 metres in the LEDs. The camera recorded the image and sent into a desktop computer. Then, computer algorithms utilized the knowledge of the modulation frequency to extract the features of the origin. This procedure is known as 'demodulation'. The demodulation of this image had to be performed at a speed that was equivalent to the speed of modulation of the origin of lighting to have a very clear image.

The team found a noticeable improvement in the image quality utilizing the modulation-demodulation technique. The time that the computer takes to do the procedure is dependent upon the picture's size. "To get a 2160 × 2160 image, the computational time is about 20 milliseconds," shares Bapan Debnath, PhD scholar in RRI along with a co-author of this analysis. That's about the size of this image containing the LEDs. His coworkers had estimated the speed in 2016.

The team repeated the experiment several times and noticed that the progress every time. Once, when the fog diverse in strength throughout the monitoring, they didn't record a noticeable improvement in the image quality. In cases like this, there was a strong breeze, and they detected fog paths across the scene. The grade of the water droplets from the atmosphere changed as time passed, and that left the modulation-demodulation procedure less powerful.

Next, the researchers altered the experimental arrangement. They made an external substance, a bit of cardboard stored at a distance of 20 centimetres in the LEDs, to signify the light into the camera. The distance between the cardboard and the camera has been 75 metres. The modulated light reflected from the cardboard travelled through the fog and was subsequently captured from the camera.  They demonstrated how their technique still considerably enhanced the quality of the resulting image.

Assessing the experiment under bright conditions, they discovered that after performing the demodulation of this origin, the image quality was large enough to differentiate the LEDs in the strongly reflected sun.

The research was partly financed by the Department of Science and Technology, Ministry of Science and Technology, Government of India.

The expense of this technique is reduced, requiring just a couple LEDs and a normal desktop computer, which may execute the procedure within a second. The method may enhance the landing techniques of aeroplanes by supplying the pilot with a fantastic perspective of beacons on the runway, significantly better than relying solely on mirrored radio waves as is currently the case. The method can help show obstacles from the road that could otherwise be hidden by fog in rail, sea, and road transport and might likewise help spotting lighthouse beacons. More study can demonstrate the effectiveness in these real life ailments. The team is exploring if the procedure can apply to transferring sources.