Algorithms exploiting light’s polarization boost resolution of commercial depth sensors 1,000-fold
MIT researchers have shown that by exploiting the polarization of light — the physical phenomenon behind polarized sunglasses and most 3-D movie systems — they can increase the resolution of conventional 3-D imaging devices as much as 1,000 times.
The technique could lead to high-quality 3-D cameras built into cellphones, and perhaps to the ability to snap a photo of an object and then use a 3-D printer to produce a replica.
Further out, the work could also abet the development of driverless cars.
“Today, they can miniaturize 3-D cameras to fit on cellphones,” says Achuta Kadambi, a PhD student in the MIT Media Lab and one of the system’s developers. “But they make compromises to the 3-D sensing, leading to very coarse recovery of geometry. That’s a natural application for polarization, because you can still use a low-quality sensor, and adding a polarizing filter gives you something that’s better than many machine-shop laser scanners.”
The researchers describe the new system, which they call Polarized 3D, in a paper they’re presenting at the International Conference on Computer Vision in December. Kadambi is the first author, and he’s joined by his thesis advisor, Ramesh Raskar, associate professor of media arts and sciences in the MIT Media Lab; Boxin Shi, who was a postdoc in Raskar’s group and is now a research fellow at the Rapid-Rich Object Search Lab; and Vage Taamazyan, a master’s student at the Skolkovo Institute of Science and Technology in Russia, which MIT helped found in 2011.
When polarized light gets the bounce
If an electromagnetic wave can be thought of as an undulating squiggle, polarization refers to the squiggle’s orientation. It could be undulating up and down, or side to side, or somewhere in-between.
Polarization also affects the way in which light bounces off of physical objects. If light strikes an object squarely, much of it will be absorbed, but whatever reflects back will have the same mix of polarizations that the incoming light did. At wider angles of reflection, however, light within a certain range of polarizations is more likely to be reflected.
This is why polarized sunglasses are good at cutting out glare: Light from the sun bouncing off asphalt or water at a low angle features an unusually heavy concentration of light with a particular polarization. So the polarization of reflected light carries information about the geometry of the objects it has struck.
This relationship has been known for centuries, but it’s been hard to do anything with it, because of a fundamental ambiguity about polarized light. Light with a particular polarization, reflecting off of a surface with a particular orientation and passing through a polarizing lens is indistinguishable from light with the opposite polarization, reflecting off of a surface with the opposite orientation.
This means that for any surface in a visual scene, measurements based on polarized light offer two equally plausible hypotheses about its orientation. Canvassing all the possible combinations of either of the two orientations of every surface, in order to identify the one that makes the most sense geometrically, is a prohibitively time-consuming computation.
Polarization plus depth sensing
To resolve this ambiguity, the Media Lab researchers use coarse depth estimates provided by some other method, such as the time a light signal takes to reflect off of an object and return to its source. Even with this added information, calculating surface orientation from measurements of polarized light is complicated, but it can be done in real-time by a graphics processing unit, the type of special-purpose graphics chip found in most video game consoles.
The researchers’ experimental setup consisted of a Microsoft Kinect — which gauges depth using reflection time — with an ordinary polarizing photographic lens placed in front of its camera. In each experiment, the researchers took three photos of an object, rotating the polarizing filter each time, and their algorithms compared the light intensities of the resulting images.
On its own, at a distance of several meters, the Kinect can resolve physical features as small as a centimeter or so across. But with the addition of the polarization information, the researchers’ system could resolve features in the range of tens of micrometers, or one-thousandth the size.
Read more: Making 3-D imaging 1,000 times better
The Latest on: 3-D imaging
via Google News
The Latest on: 3-D imaging
- Business specializes in ultrasound imageson January 11, 2020 at 11:47 am
Frontview Street in Dodge City. Middlebrooks plans to deliver her fourth child Timothy in a Wichita hospital, but it is here, with small-business owner and ultrasound technician Stevie Garcia, where ...
- ReadCoor, Inc. Announces $27 Million Series B Financing for Commercial Launch of 3D RNA, DNA, and Protein Spatial Sequencing Platformon January 10, 2020 at 5:08 am
To overcome these challenges and integrate these methods, we created an all-in-one solution with unparalleled capacity for true multi-omic spatial sequencing with high-resolution 3D imaging, robust ...
- LBIC acquires MILabs' new diagnostic X-Ray CT system to extend its preclinical imaging capabilitieson January 10, 2020 at 3:58 am
To further extend its preclinical imaging capabilities, LBIC recently acquired a MILabs uCT diagnostic X-ray CT system. This system has the unique ability to rapidly acquire dynamic 4D CT images at ...
- Here's How Automotive 3D Imaging Market Growing by 2029 | Continental AG, Denso Corporation and Quanergy Systems Inc.on January 10, 2020 at 1:55 am
Comprehensive enlightenment in the “January 2020 | Global Automotive 3D Imaging Market: Future Challenges, Production, Demand Analysis And Outlook To 2029“, addressing growing demand with advancement ...
- 3D Imaging Sensor Market 2020 Global Key Players, Size, Trends, Applications & Growth Opportunities - Analysis to 2025on January 9, 2020 at 9:16 am
The report published on the global 3D Imaging Sensor market is a comprehensive analysis of the market providing an overview covered with product definition and applications. The market status and size ...
- Grain structure control during metal 3D printing by high-intensity ultrasoundon January 9, 2020 at 2:34 am
Additive manufacturing (AM) of metals, also known as metal 3D printing, typically leads to the formation of columnar grain structures ... Using the titanium alloy Ti-6Al-4V as a model alloy, we employ ...
- Ultrasound can make stronger 3-D-printed alloyson January 9, 2020 at 2:02 am
By simply switching the ultrasound generator on and off during printing, the team also showed how specific parts of a 3-D printed object can be made with different microscopic structures and ...
- 3D Laparoscopy Imaging Systems Market Impact of Drivers, Challenges and Forecast 2019-2026on January 8, 2020 at 1:04 pm
The 3D Laparoscopy Imaging Systems Market Report 2018 is an in depth study analyzing the current state of the 3D Laparoscopy Imaging Systems Market. It provides brief overview of the market focusing ...
- 3D Sensors Market Analysis & Outlook During the Forecast Period, 2020-2024 - ResearchAndMarkets.comon January 8, 2020 at 7:33 am
These devices use cameras with 3D sensors to perform various functions such as 3D imaging, position tracking, depth sensing, and gesture recognition. Also, the aerospace and defense sector has been ...
- Teledyne: Instrumentation And Digital Imaging Driving The Stockon January 7, 2020 at 5:50 pm
Teledyne’s digital imaging solutions consist of high-performance image sensors, smart cameras and systems. In addition, the company offers LIDAR systems for airborne terrestrial mapping, mobile ...
via Bing News