Better Image in Low Light - Breakthrough Sensor Technology

Kodak's new sensor technology provides a significant increase in sensitivity to light when compared to current sensor designs. With this new technology, users will realize a 2x to 4x increase in sensitivity (from one to two photographic stops), which will improve performance when taking pictures under low light and reduce motion blur when imaging moving subjects. In addition, this technology enables the design of smaller pixels (leading to higher resolutions in a given optical format) while retaining imaging performance. This breakthrough advances an existing Kodak technology that has become a standard in digital imaging. 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. Current Technology Today, almost all color image sensors are designed using the "Bayer Pattern" an arrangement of red, green, and blue (RGB) pixels that was first developed by Kodak scientist Dr. Bryce Bayer in 1976. A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. The term derives from the name of its inventor, Dr. Bryce E. Bayer of Eastman Kodak, and refers to a particular arrangement of color filters used in most single-chip digital image sensors to create a color image. In this design, half of the pixels on the sensor are used to collect green light, with the remaining pixels evenly split between sensitivity to red and blue light. After exposure, software is used to reconstruct a full RGB image at each pixel in the final image. This design is currently the de facto standard for generating color images with a single image sensor, and is widely used throughout the industry. New Technology The new approach builds upon the standard Bayer pattern by adding panchromatic pixels – pixels that are sensitive to all visible wavelengths - to the RGB pixels present on the sensor. Since no wavelengths of visible light are excluded, these panchromatic pixels allow a (black and white) image to be detected with high sensitivity. The remaining RGB pixels present on the sensor are then used to collect color information, which is combined with the information from the pan pixels to generate the final image. Note that this is not one single pattern, but a concept - the use of panchromatic pixels to increase the overall sensitivity of the sensor. Depending on the application, different patterns may be more appropriate for use. For example, one natural trade-off is the balance between the sensor’s overall sensitivity (via the pan pixels) and how well the sensor collects color information (via the RGB pixels). The highest sensitivity would come from a sensor composed only of pan pixels, but would provide no color information. By changing the ratio of pan to RGB pixels, applications with different sensitivity and color needs can be best accommodated. Other considerations might be the ease of image reconstruction (i.e., patterns optimized for applications where reduced processing power is available), or for backward compatibility with video subsystems (where the raw data from the sensor easily decimates to a standard Bayer RGB pattern for input into video processors). This technology increases the overall sensitivity of the sensor, as more of the photons striking the sensor are collected and used to generate the final image. This provides an increase in the photographic speed of the sensor, which can be used to improve performance when imaging under low light, enable faster shutter speeds (to reduce motion blur when imaging moving subjects), or the design of smaller pixels (leading to higher resolutions in a given optical format) while retaining performance.