While 3-D printers have become relatively cheap and available, 3-D scanners have lagged well behind. But now, an algorithm developed by Brown University researchers my help bring high-quality 3-D scanning capability to off-the-shelf digital cameras and smartphones.
"One of the things my lab has been focusing on is getting 3-D image capture from relatively low-cost components," said Gabriel Taubin, a professor in Brown's School of Engineering. "The 3-D scanners on the market today are either very expensive, or are unable to do high-resolution image capture, so they can't be used for applications where details are important."
Most high-quality 3-D scanners capture images using a technique known as structured light. A projector casts a series of light patterns on an object, while a camera captures images of the object. The ways in which those patterns deform over and around an object can be used to render a 3-D image. But for the technique to work, the pattern projector and the camera have to precisely synchronized, which requires specialized and expensive hardware.
The algorithm Taubin and his students have developed, however, enables the structured light technique to be done without synchronization between projector and camera, which means an off-the-shelf camera can be used with an untethered structured light flash. The camera just needs to have the ability to capture uncompressed images in burst mode (several successive frames per second), which many DSLR cameras and smartphones can do.
The researchers presented a paper describing the algorithm last month at the SIGGRAPH Asia computer graphics conference.
The problem in trying to capture 3-D images without synchronization is that the projector could switch from one pattern to the next while the image is in the process of being exposed. As a result, the captured images are mixtures of two or more patterns. A second problem is that most modern digital cameras use a rolling shutter mechanism. Rather than capturing the whole image in one snapshot, cameras scan the field either vertically or horizontally, sending the image to the camera's memory one pixel row at a time. As a result, parts of the image are captured a slightly different times, which also can lead to mixed patterns.
"That's the main problem we're dealing with," said Daniel Moreno, a graduate student who led the development of the algorithm. "We can't use an image that has a mixture of patterns. So with the algorithm, we can synthesize images--one for every pattern projected--as if we had a system in which the pattern and image capture were synchronized."
After the camera captures a burst of images, algorithm calibrates the timing of the image sequence using the binary information embedded in the projected pattern. Then it goes through the images, pixel by pixel, to assemble a new sequence of images that captures each pattern in its entirety. Once the complete pattern images are assembled, a standard structured light 3D reconstruction algorithm can be used to create a single 3-D image of the object or space.
In their SIGGRAPH paper, the researchers showed that the technique works just as well as synchronized structured light systems. During testing, the researchers used a fairly standard structured light projector, but team envisions working to develop a structured light flash that could eventually be used as an attachment to any camera, now that there's an algorithm that can properly assemble the images.
"We think this could be a significant step in making precise and accurate 3-D scanning cheaper and more accessible," Taubin said.
Kevin Stacey | EurekAlert!
Next Generation Cryptography
20.03.2018 | Fraunhofer-Institut für Sichere Informationstechnologie SIT
TIB’s Visual Analytics Research Group to develop methods for person detection and visualisation
19.03.2018 | Technische Informationsbibliothek (TIB)
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
19.03.2018 | Event News
16.03.2018 | Event News
13.03.2018 | Event News
22.03.2018 | Trade Fair News
22.03.2018 | Earth Sciences
22.03.2018 | Earth Sciences