New camera may capture distant images without long lens

April 17, 2017

Houston, Apr 17: Scientists, including one of Indian origin, have developed a unique camera that can capture detailed images of distant objects without using a long lens, an advance that could lead to telescopes that are less bulky. The system known as SAVI – for “Synthetic Apertures for long-range, subdiffraction-limited Visible Imaging” – does not need a long lens to take a picture of a faraway object, researchers said.The prototype built by researchers reads a spot illuminated by a laser and captures the “speckle” pattern with a camera sensor.

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The prototype built by researchers reads a spot illuminated by a laser and captures the “speckle” pattern with a camera sensor.

Raw data from dozens of camera positions is fed to a computer programme that interprets it and constructs a high-resolution image.Researchers including those from Rice University in the US, built and tested the device that compares interference pat terns between multiple speckled images. Like the technique used to achieve the “Matrix” special effect, the images are taken from slightly different angles, but with one camera that is moved between shots instead of many fired in sequence. The prototype only works with coherent illumination sources such as lasers.

However, it is a step toward a SAVI camera array for use in visible light, researchers said. The speckles serve as reference beams and essentially replace one of the two beams used to create holograms, researchers said. When a laser illuminates a rough surface, the viewer sees grain-like speckles in the dot, as some of the returning light scattered from points on the surface has to go farther and throws the collective wave out of phase. The texture of a piece of paper – or even a fingerprint -is enough to cause the effect.

“Today, the technology can be applied only to coherent (laser) light,” said Ashok Veeraraghavan of Rice University.”That means you cannot apply these techniques to take pictures outdoors and improve resolution for sunlit images -as yet,” Veeraraghavan said.”With a traditional camera, the larger the physical size of the aperture, the better the resolution,” he said.

“If you want an aperture that is half a foot, you may need 30 glass surfaces to remove aberrations and create a focused spot.
This makes your lens very big and bulky,” he added. SAVI"s “synthetic aperture” sidesteps the problem by replacing a long lens with a computer programme the resolves the speckle data into an image, researchers said.

“You can capture interference patterns from a fair distance,” Veeraraghavan said. The research was published in the journal Science Advances.

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Agencies
July 25,2020

In a study conducted in 117 countries, researchers have found that the world is experiencing the most dramatic reduction in the seismic noise (the hum of vibrations in the planet's crust) in recorded history due to global COVID-19 lockdowns.

Measured by instruments called seismometers, seismic noise is caused by vibrations within the Earth, which travel like waves and the waves can be triggered by earthquakes, volcanoes, and bombs - but also by daily human activity like travel and industry.

This quiet period was likely caused by the total global effect of social distancing measures, closure of services and industry, and drops in tourism and travel, the study published in the journal Science, reported.

The new research, led by the Royal Observatory of Belgium and five other institutions around the world including Imperial College London (ICL), showed that the dampening of 'seismic noise' caused by humans was more pronounced in more densely populated areas.

"Our study uniquely highlights just how much human activities impact the solid Earth, and could let us see more clearly than ever what differentiates human and natural noise," said study co-author Stephen Hicks from ICL in the UK.

For the findings, the research team looked at seismic data from a global network of 268 seismic stations in 117 countries and found significant noise reductions compared to before any lockdown at 185 of those stations.

Researchers tracked the 'wave' of quietening between March and May as worldwide lockdown measures took hold.

The largest drops in vibrations were seen in the most densely populated areas, like Singapore and New York City, but drops were also seen in remote areas like Germany's the Black Forest and Rundu in Namibia.

Citizen-owned seismometers, which tend to measure more localised noise, noted large drops around universities and schools around Cornwall, UK and Boston, US - a drop in noise 20 per cent larger than seen during school holidays.

The findings showed that countries like Barbados, where lockdown coincided with the tourist season, saw a 50 per cent decrease in noise.

"The changes have also given us the opportunity to listen in to the Earth's natural vibrations without the distortions of human input," the study authors wrote.

Earlier in April, a study published in the journal Nature, reported at least a 30 per cent reduction in that amount of ambient human noise since lockdown began in Belgium.

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Agencies
June 8,2020

Washington DC, Jun 8: Astronomers acting on a hunch have likely resolved a mystery about young, still-forming stars and regions rich in organic molecules closely surrounding some of them.

They used the National Science Foundation's Karl G Jansky Very Large Array (VLA) to reveal one such region that previously had eluded detection and that revelation answered a longstanding question.

The regions around the young protostars contain complex organic molecules which can further combine into prebiotic molecules that are the first steps on the road to life.

The regions, dubbed "hot corinos" by astronomers, are typically about the size of our solar system and are much warmer than their surroundings, though still quite cold by terrestrial standards.

The first hot corino was discovered in 2003 and only about a dozen have been found so far. Most of these are in binary systems, with two protostars forming simultaneously.

Astronomers have been puzzled by the fact that, in some of these binary systems, they found evidence for a hot corino around one of the protostars but not the other.

"Since the two stars are forming from the same molecular cloud and at the same time, it seemed strange that one would be surrounded by a dense region of complex organic molecules and the other wouldn't," said Cecilia Ceccarelli, of the Institute for Planetary Sciences and Astrophysics at the University of Grenoble (IPAG) in France.

The complex organic molecules were found by detecting specific radio frequencies, called spectral lines, emitted by the molecules. Those characteristic radio frequencies serve as "fingerprints" to identify the chemicals.

The astronomers noted that all the chemicals found in hot corinos had been found by detecting these "fingerprints" at radio frequencies corresponding to wavelengths of only a few millimetres.

"We know that dust blocks those wavelengths, so we decided to look for evidence of these chemicals at longer wavelengths that can easily pass through dust," said Claire Chandler of the National Radio Astronomy Observatory, and principal investigator on the project.

"It struck us that dust might be what was preventing us from detecting the molecules in one of the twin protostars," added Chandler.

The astronomers used the VLA to observe a pair of protostars called IRAS 4A, in a star-forming region about 1,000 light-years from Earth. They observed the pair at wavelengths of centimetres.

At those wavelengths, they sought radio emissions from methanol, CH3OH (wood alcohol, not for drinking). This was a pair in which one protostar clearly had a hot corino and the other did not, as seen using the much shorter wavelengths.

The result confirmed their hunch. "With the VLA, both protostars showed strong evidence of methanol surrounding them. This means that both protostars have hot corinos. The reason we did not see the one at shorter wavelengths was because of dust," said Marta de Simone, a graduate student at IPAG who led the data analysis for this object.

The astronomers cautioned that while both hot corinos now are known to contain methanol, there still may be some chemical differences between them. That, they said, can be settled by looking for other molecules at wavelengths not obscured by dust.

"This result tells us that using centimetre radio wavelengths is necessary to properly study hot corinos," Claudio Codella of Arcetri Astrophysical Observatory in Florence, Italy, said.

"In the future, planned new telescopes such as the next-generation VLA and SKA, will be very important to understanding these objects," added Codella.

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Agencies
June 22,2020

New delhi, Jun 22: As consumer sentiment runs high amid growing chorus for boycotting Chinese goods in the country, the fluid market situation offers new opportunities for various smartphone makers, especially the non-Chinese ones like Samsung, Apple, Nokia, Asus and others, to realign their strategies and regain the lost market share in the face of fierce Chinese competition.

The challenge here would be not to look "opportunistic" and leverage the current explosive situation on just riding on the anti-Chinese sentiment but to offer real challenges in the form of top-end devices with solid internals at affordable price points, feel industry experts.

"The current market conditions in India are fluid and open up new opportunities for smartphone original equipment manufacturers (OEMs) to focus and leverage," Prabhu Ram, Head-Industry Intelligence Group, CyberMedia Research (CMR), told IANS.

In the first quarter (January-March) this year, Samsung's shipments were driven by its upgraded A and M series (A51, A20s, A30s, and M30s).

According to Counterpoint Research, Samsung managed to hold third position in Q1 2020 due to launches across several price tiers, especially in the affordable premium segment (S10 Lite, Note 10 Lite).

The South Korean smartphone maker last week announced a Rs 4,000 price drop on its popular Galaxy Note10 Lite smartphone that will now cost Rs 37,999 (6GB variant).

Earlier this month, Samsung launched two new smartphones, Galaxy M11 and Galaxy M01, with powerful batteries under Rs 15,000 in India.

Galaxy M11 comes in two variants. The 3GB+32GB will be priced at Rs 10,999 while the higher 4GB+64GB variant will be available for Rs 12,999.

Samsung has also launched an affordable Galaxy A21s smartphone with quad-camera system and 5,000mAh battery at a starting price of Rs 16,499.

Also read: Boycott China? OnePlus 8 Pro sold out within minutes of going on sale

On the other hand, Apple grew a strong 78 per cent YoY driven by strong shipments of iPhone 11 and multiple discounts on platforms like Flipkart and Amazon in Q1, according to Counterpoint.

Apple has also brought its cheapest yet powerful new iPhone SE that costs Rs 38,900 (64GB) in India with a special offer from HDFC Bank. The new iPhone SE is powered by the Apple-designed A13 Bionic, the fastest chip in a smartphone and features the best single-camera system ever in an iPhone.

According to Tarun Pathak, Associate Director, Counterpoint Research, consumer sentiments are running high and a section of users will look for alternatives, benefitting global and Indian brands.

"However, we do not think non-Chinese brands will run aggressive campaigns based on the situation as it might look like being opportunistic," Pathak told media.

It may actually let brands of Chinese origin try to run aggressive campaigns on their presence and scale.

"Some of these Chinese brands have been active in scaling up local value addition, creating jobs and investing in research and development," Pathak noted.

On Saturday, market leader Xiaomi said that it is "more Indian" than any other smartphone brand.

The company's India head Manu Kumar Jain said that the company's mobile phone R&D centre and product team is in India, it employs 50,000 people in the country, the entire leadership team is Indian and that the company pays its taxes in India.

Earlier, Realme India CEO Madhav Sheth who is also very active on social media said that Realme is an Indian startup.

In his latest episode of Ask Madhav' series on YouTube, Sheth said: "I can proudly say Realme is an Indian startup, which is now a global MNC (multinational corporation)".

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