It was in the 1830s that English scientist and inventor Sir Charles Wheatstone conceptualized the idea of stereoscopy: the three-dimensional vision produced by the pairing of two slightly different views of the same image on each retina. Since then the technology has evolved through iterations with names such as the Plastoscope, the Perfecscope and the View-Master. The first 3D motion pictures appeared in 1899 and in the past 120 years the form has come in and out of fashion many times.
One possible reason for the ebb and flow of the popularity of stereoscopic cinematography may be a condition known as 3D fatigue. 3D fatigue is a condition that can afflict viewers of stereoscopic images and videos with symptoms that include blurred vision, sickness, fatigue, headache, double vision and pain in or around the eyes. Researchers and professional cinematographers have found that stereoscopic content, if not well produced, can bring 3D fatigue to viewers.
While 3D fatigue may still be on the fringe of our collective cultural consciousness, with the recent proliferation of 3D films that followed James Cameron’s Avatar and the growing availability of inexpensive stereoscopic technology such as stereoscopic digital cameras, 3D mobile devices, 3D televisions and computer monitors that will enable amateurs as well as professionals to embrace stereoscopy, we may soon be experiencing 3D fatigue in theaters, at home, in the office, and on the go.
But not if Feng Liu, Assistant Professor in the Department of Computer Science at Portland State University, has anything to say about it. Dr. Liu, in collaboration with other researchers in the Computer Graphics & vision Lab at PSU and Adobe Systems Inc., has developed two new technologies for editing stereoscopic images and videos: one that can help both amateurs and professionals create more pleasant 3D experience by addressing the source of 3D fatigue: a disparity between the two images that provides the illusion of depth; and another that allows for warping (a processing technique to digitally manipulate shapes) of stereoscopic images.
“The application of this technology,” Dr. Liu said, speaking of his algorithm for camera-oriented disparity editing, “is stereoscopic content production with the aim of reducing, if not eliminating 3D fatigue in movies.”
The source of 3D fatigue is in the production of stereoscopic images and videos, Dr. Liu explained. In filming stereoscopic movies there is a 3D comfort zone, a place to position the 3D objects. Film in this zone and you get results like Cameron did in Avatar, film out of it and you’ll make your audience sick. For most people experimenting with stereoscopic cinematography, those who don’t have James Cameron’s experience, budget, or crew, Dr. Liu’s editing technology will allow them to drop their videos into a program like Adobe Premiere Pro and edit their way into the comfort zone.
Referring to the algorithms he developed to enable the warping of stereoscopic images, Dr. Liu said: “It’s easy to take a 2d image and rotate or warp it using programs like Photoshop, but with stereoscopic photography warping is much more difficult. When you rotate a stereoscopic image you introduce the kind of disparities that can cause 3D fatigue and break the 3D depth perception of the objects and scene.”
Dr. Liu and his team developed a unified technology that can extend monocular (2D) warping techniques and enables them on stereoscopic images without modifying each of them individually.
In keeping with its mission to promote the use and increase the impact of Portland State University innovations, the office of Innovation & Intellectual property has arranged for the joint ownership of Dr. Liu’s algorithms for editing 3D images and videos between PSU and Adobe and has filed provisional patent applications for both technologies.
Dr. Liu’s background in 2D computer graphics, computational topography and cinematography, not to mention his history of collaborative projects with Adobe have provided him with the tools needed to be a pioneer in the development of stereoscopic image and video editing.
“I can imagine,” Dr. Liu said, “that within the next ten years we will have 3D versions of programs like Photoshop and Premiere Pro, and that we’ll be able to do as much with 3D editing as we can now do with 2D. Right now technologies such as these are limited to professionals, but they won’t be for long. In the lab we’re working to increase the opportunities in 3D editing for amateurs and professionals alike.”