SPIE Professional October 2010
Stanford University's open-source digital photography software platform, "Frankencamera," which allows users to create novel camera capabilities, is now available as a free download for Nokia N900 mobile computers.
"We are releasing code so that people can create new imaging applications," says Stanford professor Marc Levoy, who leads the Frankencamera engineering team.
The revolutionary open-source camera could be used to extend a camera's dynamic range, or its ability to handle a wide range of lighting in a single frame. The process of high-dynamic-range imaging is to capture pictures of the same scene with different exposures and then to combine them into a composite image in which every pixel is optimally lit. Until now, this was done with photo software or by dodging and burning in a darkroom.
Stanford researchers released the source code for implementation of the Frankencamera architecture and FCam API on the Nokia N900 smartphone in July. A binary executable was also released, which can be downloaded to any retail N900 without bricking the phone, thereby making its camera programmable.
The Stanford researchers also have been awarded a $1 million National Science Foundation grant, shared with colleagues at MIT, to make professional-style, single-lens reflex (SLR) cameras, equipped with the software platform, for free distribution to computational photography professors around the United States. Non-academics could buy the camera at cost.
As of summer 2010, this package has been used in two courses - at Stanford University (co-taught by Levoy and Fredo Durand) and at ETH Zurich (taught by Marc Pollefeys). In both courses Nokia N900s were loaned to every student, and assignment #1 was to replace its autofocus algorithm. (The phone's camera, while small, has a movable lens.) Grading was based on the accuracy with which the students could focus on a test scene, as well as focusing speed in milliseconds. An assignment like this would have been impossible before FCam.
Two of the students submitted algorithms that were better than Nokia's; these were presented in Finland at the conclusion of the course. The students also did interesting projects for the course, some of which might be submitted for publication over the coming year.
Frankencamera began in 2006 with the idea that computational photography shouldn't be relegated to klunky equipment in academic labs. Instead, it should be developed for use in the field on portable, consumer-friendly cameras.
High-dynamic-range (HDR) photography is a built-in feature in Apple's iPhone 4. The iPhone camera can take three photos with different exposure levels in quick succession. It then processes the photos into one image.
The HDR feature is available with the iPhone's proprietary 4.1 software and from apps developed by third-party developers.