Nav: Home

Picture perfect

July 31, 2017

When taking a picture, a photographer must typically commit to a composition that cannot be changed after the shutter is released. For example, when using a wide-angle lens to capture a subject in front of an appealing background, it is difficult to include the entire background and still have the subject be large enough in the frame.

Positioning the subject closer to the camera will make it larger, but unwanted distortion can occur. This distortion is reduced when shooting with a telephoto lens, since the photographer can move back while maintaining the foreground subject at a reasonable size. But this causes most of the background to be excluded. In each case, the photographer has to settle for a suboptimal composition that cannot be modified later.

As described in a technical paper to be presented July 31 at the ACM SIGGRAPH 2017 conference, UC Santa Barbara Ph.D. student Abhishek Badki and his advisor Pradeep Sen, a professor in the Department of Electrical and Computer Engineering, along with NVIDIA researchers Orazio Gallo and Jan Kautz, have developed a new system that addresses this problem. Specifically, it allows photographers to compose an image post-capture by controlling the relative positions and sizes of objects in the image.

Computational Zoom, as the system is called, allows photographers the flexibility to generate novel image compositions -- even some that cannot be captured by a physical camera -- by controlling the sense of depth in the scene, the relative sizes of objects at different depths and the perspectives from which the objects are viewed.

For example, the system makes it possible to automatically combine wide-angle and telephoto perspectives into a single multi-perspective image, so that the subject is properly sized and the full background is visible. In a standard image, the light rays travel in straight lines into the camera at an angle specified by the focal length of the lens (the field of view angle). However, this new functionality allows photographers to produce physically impossible images in which the light rays "bend," changing from a telephoto to a wide angle as they go through the scene.

Achieving the custom composition is a three-step process. First, the photographer must capture a "stack" of multiple images, moving the camera gradually closer to the scene between shots without changing the focal length of the lens. The system then uses the captured image stack, and a standard structure-from-motion algorithm, to automatically estimate the camera position and orientation for each image. Next, a novel multi-view 3D reconstruction method estimates "depth maps" for each image in the stack. Finally, all of this information is used to synthesize multi-perspective images which have novel compositions through a user interface.

"This new framework really empowers photographers by giving them much more flexibility later on to compose their desired shot," said Pradeep Sen. "It allows them to tell the story they want to tell."

"Computational Zoom is a powerful technique to create compelling images," said Gallo, NVIDIA senior research scientist. "Photographers can manipulate a composition in real time, developing plausible images that cannot be captured with a physical camera."

Eventually, the researchers hope to integrate the system as a plug-in to existing image-processing software, allowing a new kind of post-capture compositional freedom for professional and amateur photographers alike.

Find out more about the project, or see results of the post-capture method on YouTube.
-end-


University of California - Santa Barbara

Related Angle Articles:

Wave beams mix and stir the ocean to create climate
Waves deep within the ocean play an important role in establishing ocean circulation, arising when tidal currents oscillate over an uneven ocean bottom.
Bird feathers inspire researchers to produce vibrant new colors
Nagoya University team replicates unique color of bird plumage. Raspberry-like particle systems simulate the spongy texture of Stellar's jay's blue feathers.
Adjusting solar panel angles a few times a year makes them more efficient
With Earth Day approaching, new research from Binghamton University-State of New York could help US residents save more energy, regardless of location, if they adjust the angles of solar panels four to five times a year.
Subtle steric differences reveal a model for Ni cross-coupling success
Princeton researchers have developed a predictive model may enable challenging metal-catalyzed cross couplings reactions that are indispensable to drug development.
New electron source for materials analysis
Jülich physicists have succeeded in accelerating the determination of material properties as well as making it more efficient.
More Angle News and Angle Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Teaching For Better Humans
More than test scores or good grades — what do kids need to prepare them for the future? This hour, guest host Manoush Zomorodi and TED speakers explore how to help children grow into better humans, in and out of the classroom. Guests include educators Olympia Della Flora and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...