New Kodak Image Sensors for Low-Light Photography

New Kodak camera technology could make dark, blurry photos as thing of the past

Eastman Kodak Company today announced what it considers a “groundbreaking advancement” in image sensor technology that will help reduce the accidental taking of dark and blurry digital photos. Kodak claims its new sensor technology provides a two- to four-fold increase in sensitivity to light (from one to two photographic stops) compared to current sensor designs.

“This represents a new generation of image sensor technology and addresses one of the great challenges facing our industry – how to capture crisp, clear digital images in a poorly lit environment,” said Chris McNiffe, General Manager of Kodak’s Image Sensor Solutions group. “This is a truly innovative approach to improving digital photography in all forms, and it highlights Kodak’s unique ability to differentiate its products by delivering advanced digital technologies that really make a difference to the consumer.”

Image sensors convert light into electric charge to capture images. Today, the design of almost all color image sensors is based on the Bayer Pattern, an arrangement of red, green, and blue pixels that was first developed by Kodak scientist Dr. Bryce Bayer in 1976. In this design, half of the pixels on the sensor are used to collect green light, with the remaining pixels split evenly between sensitivity to red and blue light. After exposure, software reconstructs a full color signal for each pixel in the final image.

Kodak’s new proprietary technology, invented by John Compton and John Hamilton, adds panchromatic, or clear pixels to the red, green, and blue elements that form the image sensor array. Since these pixels are sensitive to all wavelengths of visible light, they collect a significantly higher proportion of the light striking the sensor. By matching these pixel arrangements with advanced software algorithms from Kodak that are optimized for these new patterns, users can realize an increase in photographic speed, directly improving performance when taking pictures under low light.

Inventor John Hamilton explains in the Kodak blog, “One way that helps to think about this is to look at it in terms of luminance and chrominance. In the original Bayer design, the green pixels are used to recover most of the luminance information from the image. Now, we are using panchromatic pixels - which are more sensitive than green pixels, because none of the photons get filtered out or wasted - to act as the luminance. This gives us a more sensitive luminance channel in the final image, which raises the sensitivity of the entire sensor.”

John Compton adds, “The real advantage is that the panchromatic pixels are more sensitive, since they detect all wavelengths of visible light (rather than filtering light to detect color information).” Hamilton points out that the improved images don’t come from using panchromatic pixels, but rather the more accurate luminance data.

Kodak’s new technology also enables faster shutter speeds (to reduce motion blur when imaging moving subjects), as well as the design of smaller pixels (leading to higher resolutions in a given optical format) while retaining performance.

As for which situations benefit most from the improved sensor, Hamilton says, “In situations where you want more sensitivity to light. In a low-light situation, these new patterns will produce a lot less color noise than a Bayer pattern sensor. You can run the shutter faster, which gets rid of a lot of motion artifacts. It will cut down on camera shake or, if you're taking a picture of a moving object there will be less blur.”

“Another way to think of this is that you have the same number of photons coming into the new sensor as you would with the Bayer pattern,” adds Compton. “It's just that the new filter arrays waste fewer of the photons since fewer of them end up absorbed in a color filter.”

The inventors say that the technology is appropriate for use with both CCD and CMOS image sensors, and that Kodak is developing this technology for consumer markets such as digital still cameras and camera phones. The technology may also be applied to other image sensor devices for industrial and scientific imaging. The first Kodak sensor to use this technology is expected to be available for sampling in the first quarter of 2008.

Kodak’s announcement comes on the heels of advancements in low-light photography made by South Korea's Electronic Technology Institute. The institute announced in late May that it had developed an image sensor for use in extreme low-light conditions and would be suitable for use in tunnels, night clubs and bars.

Reference:Marcus Yam,dailytech