US technology company Rambus has unveiled 'Binary Pixel' sensor technology, promising greatly expanded dynamic range for the small sensors used in devices such as smartphones. Current image sensors are unable to record light above a specific saturation point, which results in clipped highlights. Binary Pixel technology gets around this by recording when a pixel has received a certain amount of light, then resetting it and in effect restarting the exposure. The result is significantly expanded dynamic range from a single-shot exposure. The company has demonstrated the technology using a low resolution (128 x 128 pixel) sensor, and says it can easily be incorporated into CMOS sensors using current manufacturing methods.

Aside from the 'temporal oversampling' described above, Binary Pixel technology employs a couple of further innovations. It uses Binary Operation, sensing photons using discrete thresholds which the company says is similar to the human eye for better sensitivity across gamut of dark to bright. It also employs Spatial Oversampling, meaning the individual pixels are sub-divided to capture more data and improve dynamic range. The technology isn't restricted to phone sensors, and in principle should work equally well for all sensor sizes.

Rambus lists the key advantages of Binary Pixel sensors as follows:

Ultra-High Dynamic Range
• Optimized at the pixel level for DSLR-quality dynamic range in mobile and consumer cameras 

Single-Shot HDR Photos & Videos
• Operates in a single exposure period to capture HDR images real-time with no post processing

Improved Low-Light Sensitivity
• Spatial and temporal oversampling reduces noise and graininess

Works with Current Mobile Platform
• Designed to integrate with current SoCs, be manufactured using current CMOS technology, and fit in a comparable form-factor, cost and power envelope

Press release:

Rambus Unveils Binary Pixel Technology For Dramatically Improved Image Quality in Mobile Devices

 Image comparison illustrating the theoretical benefits of the Binary Pixel Imager 

Breakthrough technology Provides Single-Shot High Dynamic Range and Improved Low-Light Sensitivity in a Single Exposure

SUNNYVALE, CALIFORNIA AND BARCELONA, SPAIN – February 25, 2013 – Rambus Inc. (NASDAQ: RMBS), the innovative technology solutions company that brings invention to market, today unveiled breakthrough binary pixel technology that dramatically improves the quality of photos taken from mobile devices. The Rambus Binary Pixel technology includes image sensor and image processing architectures with single-shot high dynamic range (HDR) and improved low-light sensitivity for better videos and photos in any lighting condition.

“Today’s compact mainstream sensors are only able to capture a fraction of what the human eye can see,” said Dr. Martin Scott, chief technology officer at Rambus. “Our breakthrough binary pixel technology enables a tremendous performance improvement for compact imagers capable of ultra high-quality photos and videos from mobile devices.”

As improvements are made in resolution and responsiveness, more and more consumers are using the camera functionality on their smart phone as the primary method for taking photos and capturing memories. However, high contrast scenes typical in daily life, such as bright landscapes, sunset portraits, and scenes with both sunlight and shadow, are difficult to capture with today’s compact mobile sensors - the range of bright and dark details in these scenes simply exceeds the limited dynamic range of mainstream CMOS imagers.

This binary pixel technology is optimized at the pixel level to sense light similar to the human eye while maintaining comparable form factor, cost and power of today’s mobile and consumer imagers. The results are professional-quality images and videos from mobile devices that capture the full gamut of details in dark and bright intensities.

Benefits of binary pixel technology:

  • Improved image quality optimized at the pixel level
  • Single-shot HDR photo and video capture operates at high-speed frame-rates
  • Improved signal-to-noise performance in low-light conditions
  • Silicon-proven technology for mobile form factors
  • Easily integratable into existing SoC architectures
  • Compatible with current CMOS image sensor process technology

The Rambus binary pixel has been demonstrated in a proof-of-concept test-chip and the technology is currently available for integration into future mobile and consumer image sensors. For additional information visit www.rambus.com/binarypixel