Posted on 05/04/2019 12:20:44 AM PDT by LibWhacker
Developed in China, the lidar-based system can cut through city smog to resolve human-sized features at vast distances.
Long-distance photography on Earth is a tricky challenge. Capturing enough light from a subject at great distances is not easy. And even then, the atmosphere introduces distortions that can ruin the image; so does pollution, which is a particular problem in cities. That makes it hard to get any kind of image beyond a distance of a few kilometers or so (assuming the camera is mounted high enough off the ground to cope with Earth’s curvature).
But in recent years, researchers have begun to exploit sensitive photodetectors to do much better. These detectors are so sensitive they can pick up single photons and use them to piece together images of subjects up to 10 kilometers (six miles) away.
Nevertheless, physicists would love to improve even more. And today, Zheng-Ping Li and colleagues from the University of Science and Technology of China in Shanghai show how to photograph subjects up to 45 km (28 miles) away in a smog-plagued urban environment. Their technique uses single-photon detectors combined with a unique computational imaging algorithm that achieves super-high-resolution images by knitting together the sparsest of data points.
The new technique is relatively straightforward in principle. It is based on laser ranging and detection, or lidar—illuminating the subject with laser light and then creating an image from reflected light.
The big advantage of this kind of active imaging is that the photons reflected from the subject return to the detector within a specific time window that depends on the distance. So any photons that arrive outside this window can be ignored.
This “gating” dramatically reduces the noise created by unwanted photons from elsewhere in the environment. And it allows lidar systems to be highly sensitive and distance specific.
To make the new system even better in urban environments, Zheng-Ping and co use an infrared laser with a wavelength of 1550 nanometers, a repetition rate of 100 kilohertz, and a modest power of 120 milliwatts. This wavelength makes the system eye-safe and allows the team to filter out solar photons that would otherwise overwhelm the detector.
The researchers send and receive these photons through the same optical apparatus—an ordinary astronomical telescope with an aperture of 280 mm. The reflected photons are then detected by a commercial single-photon detector. To create an image, the researchers scan the field of view using a piezo-controlled mirror that can tilt up, down, and side to side.
In this way, they can create two-dimensional images. But by changing the gating timings, they can pick up photons reflected from different distances to build a 3D image.
The final advance the team has made is to develop an algorithm that knits an image together using the single-photon data. This kind of computational imaging has advanced in leaps and bounds in recent years, allowing researchers to create images from relatively small sets of data.
The results speak for themselves. The team set up the new camera on the 20th floor of a building on Chongming Island in Shanghai and pointed it at the Pudong Civil Aviation Building across the river, some 45 km away. single pixel resolution imaging
Conventional images taken through the telescope show nothing other than noise. But the new technique produces images with a spatial resolution of about 60 cm, which resolves building windows. “This result demonstrates the superior capability of the near-infrared single-photon LiDAR system to resolve targets through smog,” say the team.
That’s also significantly better than the conventional diffraction limit of 1 meter at 45 km, and certainly better than other recently developed algorithms. The image here shows the potential of the technique in images taken in daylight from a distance of 21 km. ”Our results open a new venue for high-resolution, fast, low-power 3D optical imaging over ultralong ranges,” say Zheng-Ping and co.
That’s interesting work that has a wide range of applications. The team mention remote sensing, airborne surveillance, and target recognition and identification. Indeed, the entire device is about the size of a large shoebox and so is relatively portable.
And Zheng-Ping and co say it can be significantly improved. “Our system is feasible for imaging at a few hundreds of kilometers by refining the setup, and thus represents a significant milestone towards rapid, low-power, and high-resolution LiDAR over extra-long ranges,” they say.
So keep smiling—they may be watching.
We have lots of Asians in our area. I get a kick out of them when they wear the surgical masks around town. (Other than the few days/weeks in summer with the fires coming in from Canada - our air is always very clean.) They do NOTHING to keep from breathing in particulates.
They are for keeping one’s own germs from spreading.
But - whatever.
From what I understand, in London, UK, you cannot walk anywhere on the streets without being picked up on multiple CCTV cameras yet, the crime rate continues to grow.
Of course, under ECHELON, the ‘Five Eyes’,(NSA, GCHQ, CSE, ASD, and GCSB), monitor ALL communications, telephone, internet, etc. The depth of the gubmint to monitor their citizens in the West would make a former ‘Staatssicherheitsdienst’ general weep with jealously.
Jim Morrison of the Doors saw it coming”
“Is everybody in? Is everybody in? Is everybody in? The ceremony is about to begin. The entertainment for this evening is not new, you’ve seen this entertainment through and through you have seen your birth, your life, your death....you may recall all the rest. Did you have a good world when you died? -enough to base a movie on??”
From the album “An American Prayer”
“The Movie”
https://www.youtube.com/watch?v=Ul5HTPES-yU
This album is pretty cool. Poetry of Morrison on tape, and then after he died, put to music by the original members. Note - some rough language. Great song though imho.
Korean porn ping?
My darling wife is from China and I have been there with her visiting her family, you are always being watched.
And what are the odds nothing is in the way? Like a tree trunk or a crowd of people or a truck or an antifa mask etc. Can it see around large objects?
How do you know they didn’t have this?
You’re assuming that it will be deployed on the ground, rather than on a stabilized mount on an aircraft.
The US military has had stuff like this on aircraft for a long time.
That's just an average. It is that value plus or minus about 6 miles. That has consequences.
Not true. I lived — and jogged — in polluted Kabul air for over 5 years. After some days I noticed black stuff when clearing my throat. Not good. It was mostly from soot from the wood burned to cook naan (flat bread). But it likely contained airborne feces from the open “sewers” down the middle of the dirt streets.
On my next trip to the USA I got a large box of masks from Home Depot. I began to wear them when jogging. The masks got black and my sputum remained clear. So yeah, they do something.
Obviously they don’t do EVERYTHING as they are like furnace air filters and particles below a certain size still get through.
It already is. But not by/in 4th dimensional means and constraints.
I do have a bunch of N95 filters (I like the ones with the easy breathing thingy in the filter). Those DO help. I’m talking about the square cloth that go over the nose and mouth - but no seal.
Although I suppose even a loose surgeon’s mask is better than nothing?
Or they could of just not gone at all as Osama was already dead.
Obama needed his big distraction though
Photograph some UFOs now.
Thanks. That was my first question.
I live in Asia. We commonly wear masks to work when we have a cold so we don’t spread it. Nice gesture. Not sure if effective.
Another issue: at a resolution of 60cm, the resulting “image” of an individual is going to be 3 or 4 pixels - NOT a lot of information detail to be had.
A two story building has 10 or 15 pixels high if you can move beyond earth curvature type issues
The technical barriers prevent this from any potential usefulness - now and for a very long time...
There are no secrets.
You are a criminal. I am a criminal. EVERYONE is a criminal.
Everything you fear about government surveillance is true. Passive surveillance is everywhere. I have seen satellite photos that could tell what book someone is reading. Every device that could listen to you, does listen to you. Going off the grid? Believe it or not you are still tracked by your heat signature.
Paranoid? I wish. I first saw these technological wonders back in the 1970’s at the National Intelligence Academy in Fort Lauderdale. It has gotten much, much worse since.
Basically, if someone in the government wants “dirt” on you, they not only can get it, they already have it. And if you think you are some kind of saint, your loved ones probably aren’t and will be used against you.
I wish I had a solution...but any way around observation has already been thought of by someone smarter than you and addressed.
What is sad is that people have given up privacy willingly. Any mobile phone can be a tracker and listening device. Ditto smart watches. Voice control on your TV? Always listening. Voice commands in your car? Recording every conversation you have and storing it on NSA servers for future reference.
We are living in Orwell’s future, and most don’t know or care. Sad.
if the Seals had this available when they were after Osama Ben Laden...
A jet blast from the past, 1956 U-2 camera specs... compare and contrast...
https://airandspace.si.edu/collection-objects/camera-aerial-hycon-73b-lockheed-u-2c
.The B camera had a 36-inch focal length and resolved features as small as .75 meters (2.5 feet) from an altitude of 19.3 kilometers (65,000 feet). Designed by Dr. James Baker, the panoramic B camera had revolutionary image-movement compensation that allowed for the motion of the aircraft and the vibration of the engine, as well as the movement of the highly sensitive, fast, and ultra thin Kodak film also especially designed for the project. Shooting through seven glass encased windows in the belly of the U-2, the B camera recorded everything along a 3,500 km (2,700 mile) course, up to 200 km (125 miles) wide, and it could provide up to 4000 pairs of stereoscopic photographs.
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