Sensor Combines Images, Video
OXFORD, England, Feb. 16, 2010 — By combining off-the-shelf technologies found in standard cameras and digital movie projectors, researchers in England developed a revolutionary way of capturing a high-resolution still image alongside very high-speed video on the same custom-built, solid-state sensor. This new technology could have applications in science, industry and consumer products.
Scientists funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the British Heart Foundation at the University of Oxford successfully created a tool that will transform many forms of detailed scientific imaging and could provide access to high-speed video with high-resolution still images from the same camera at a price suitable for the consumer market.
This could have everyday applications for everything from CCTV to sports photography and is already attracting interest from the scientific imaging sector, where the ability to capture very high quality still images that correspond exactly to very high-speed video is extremely desirable and currently very expensive to achieve.
This still image (and a corresponding 400 fps video taken at the same time), shows a drop of milk falling into a beaker of water. Both stills and video were taken at the same time, using the same camera, and represent the same image data. The still image has a 16-fold greater spatial resolution and it can be decoded into the video frames played in sequence to reveal the high-speed motion content. This image appears in the Nature Methods paper about the research.
Dr. Peter Kohl and his team study the human heart using sophisticated imaging and computer technologies. They previously created an animated model of the heart, which allows one to view the heart from all angles and look at all layers of the organ, from the largest structures right down to the cellular level. They do this by combining many different types of information about heart structure and function using powerful computers and advanced optical imaging tools. This requires a combination of speed and detail, which has been difficult to achieve using current photographic techniques.
"Anyone who has ever tried to take photographs or video of a high-speed scene, like football or motor racing, even with a fairly decent digital SLR, will know that it's very difficult to get a sharp image because the movement causes blurring," said Kohl. "We have the same problem in science, where we may miss really vital information like very rapid changes in intensity of light from fluorescent molecules that tell us about what is happening inside a cell. Having a massive 10- or 12-megapixel sensor, as many cameras now do, does absolutely nothing to improve this situation.
The still image (and a corresponding 200 fps video) shows a Ping-Pong ball rolling past a bank note. (Image courtesy Dr. Gil Bub, University of Oxford)
"Dr. Gil Bub from my team then came up with a really great idea to bring together high-resolution still images and high-speed video footage, at the same time and on the same camera chip - 'the real motion picture!' The sort of cameras researchers would normally need to get similar high-speed footage can set you back tens of thousands of pounds, but Dr. Bub's invention does so at a fraction of this cost. This will be a great tool for us and the rest of the research community and could also be used in a number of other ways that are useful to industry and consumers," Kohl said.
"What's new about this is that the picture and video are captured at the same time on the same sensor," said Bub. "This is done by allowing the camera's pixels to act as if they were part of tens, or even hundreds, of individual cameras taking pictures in rapid succession during a single normal exposure. The trick is that the pattern of pixel exposures keeps the high-resolution content of the overall image, which can then be used as-is, to form a regular high-res picture, or be decoded into a high-speed movie."
The technique works by dividing all the camera's pixels into groups that are then allowed to take their part of the bigger picture in well-controlled succession, very quickly, and during the time required to take a single 'normal' snapshot. So for example, if you use 16 pixel patterns and sequentially expose each of them for one-sixteenth of the time the main camera shutter remains open, there would be 16 time points at which evenly distributed parts of the image will be captured by the different pixel groups. You then have two choices: either you view all 16 groups together as your usual high-resolution still image, or you play the 16 sub-images one after the other, to generate a high-speed movie.
This concept has attracted the attention of Cairn Research, a UK-based scientific instrument manufacturer. "High speed imaging of biologically important processes is critical for many of our customers at Cairn Research," said Dr. Martyn Reynolds. "Frequently there is a requirement to record events in living cells that are over in a fraction of a second, and this pushes us to the limits of existing technology. For several years we have been developing a product line for fast imaging of optical slices though cells, and we are very interested in using the processes and technology developed by the group in Oxford to extend the capabilities of our devices and the scientific benefits this could bring."
The research may soon move from the optical bench to a consumer-friendly package. Dr. Mark Pitter from the University of Nottingham is planning to compress the technology into an all-in-one sensor that could be put inside normal cameras.
"The use of a custom-built solid-state sensor will allow us to design compact and simple cameras, microscopes and other optical devices that further reduce the cost and effort needed for this exciting technique. This will make it useful for a far wider range of applications, such as consumer cameras, security systems, or manufacturing control," Pitter said.
"This is a really clever, effective way of looking at real-life biological processes that started by trying to solve a research problem and is leading to whole host of opportunities," said Dr. Celia Caulcott, BBSRC director of Innovation and Skills. "It shows that it is possible for creative solutions in bioscience tools and technologies to lead to marketable products. These researchers have been successful in making their own research tools more powerful and it is to their credit that they have also thought about the wider possibilities for their new technology."
The research was published Feb. 14 in the journal Nature Methods.
The technology has been patented by Isis Innovation, the University of Oxford's technology transfer office, which provided seed funding for this development and is welcoming contact from industry partners to take the technology to market.
For more information, visit: www.isis-innovation.com
- A light-tight box that receives light from an object or scene and focuses it to form an image on a light-sensitive material or a detector. The camera generally contains a lens of variable aperture and a shutter of variable speed to precisely control the exposure. In an electronic imaging system, the camera does not use chemical means to store the image, but takes advantage of the sensitivity of various detectors to different bands of the electromagnetic spectrum. These sensors are transducers...
- In optics, an image is the reconstruction of light rays from a source or object when light from that source or object is passed through a system of optics and onto an image forming plane. Light rays passing through an optical system tend to either converge (real image) or diverge (virtual image) to a plane (also called the image plane) in which a visual reproduction of the object is formed. This reconstructed pictorial representation of the object is called an image.
- An instrument consisting essentially of a tube 160 mm long, with an objective lens at the distant end and an eyepiece at the near end. The objective forms a real aerial image of the object in the focal plane of the eyepiece where it is observed by the eye. The overall magnifying power is equal to the linear magnification of the objective multiplied by the magnifying power of the eyepiece. The eyepiece can be replaced by a film to photograph the primary image, or a positive or negative relay...
- Pertaining to optics and the phenomena of light.
- 1. A generic term for detector. 2. A complete optical/mechanical/electronic system that contains some form of radiation detector.
- Referring to the bandwidth and spectrum location of the signal produced by television or radar scanning.
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