CCD image sensors bring new parameters to low-light imaging

November 07, 2014 // By Graham Prophet
ON Semiconductors’ KAE-02150 image sensor combines Interline Transfer CCD and Electron Multiplication technology to enable very low-light video capture from sunlight to starlight for industrial applications

Combining ON Semiconductor's industry-leading Interline Transfer (IT) CCD pixel design with a newly developed electron multiplication (EM) output structure, this technology enables image sensor solutions that deliver sub-electron noise performance with CCD-class image quality and uniformity for exceptional low-light imaging. The KAE-02150 image sensor, the first device available in the technology, can capture 1080p (1920 x 1080) video in scenes with widely varying lighting conditions – from sunlight to starlight and from highlights to shadows – thereby greatly extending the imaging capability of a single camera imaging system. This is particularly useful for light-starved applications such as surveillance, defence/military, scientific and medical imaging and intelligent transportation systems.

The KAE-02150 deploys an innovative output circuit design that enables high-dynamic range imaging by allowing either conventional CCD (low-gain) or EMCCD (high-gain) outputs to be utilised on a pixel-by-pixel basis within the same image. Charge from each individual pixel is measured and the signal level is compared to a user selectable threshold in the camera system to determine where each charge packet is routed. Pixels from very low-light regions of the scene can be selectively routed to the EMCCD output, while pixels from bright regions of the image – which would typically saturate an EMCCD register and distort the image – are routed to the conventional CCD output amplifier. With this intra-scene switchable gain feature, signals from both outputs can then be re-combined, allowing one camera to properly render bright regions in a dark field of view and enabling dynamic compensation under changing conditions such as headlights entering or leaving an extreme low light scene.

According to Chris McNiffe, Vice President, Image Sensor Business Unit at ON Semiconductor, “By extending the superb image quality and uniformity of CCD devices into the extreme low-light regime, customers in industrial markets now have access to a new level of performance under the most challenging imaging conditions.”

The KAE-series is based on the TRUESENSE 5.5-micron IT-CCD platform.