Image sensor for very-low-light applications: medical imaging options expanded

November 07, 2017 //By Graham Prophet
Specialist distributor Framos (Taufkirchen, Germany) has ON Semiconductor’s KAE-04471 interline transfer EMCCD image sensor that has been configured to provide picture quality in extreme low light applications; as well as in direct sunlight.

The 4.4 Megapixel Interline Transfer EMCCD sensor features high dynamic range coupled with very low image noise for applications operating both in darkness and in variable light conditions – especially military and defence, ITS, Surveillance, scientific and medical imaging.

The square 4/3-in. sensor uses both interline transfer and electron multiplying, combining these two techniques to enable advanced ultra-low light applications that require extreme sensitivity at fast frame rates. The KAE-04471 achieves a dynamic range of 72 dB and a low readout noise of under 10 rms in normal mode. A dynamic range of 92 dB and a readout noise of under 1 rms can be achieved using the Intra-Scene switchable gain feature. The enlarged pixel size of 7.4 µm compared to the 5.5 µm pixel size in the existing KAE-02150, results in a higher sensitivity and extreme-low-light images that are similar to daylight images produced with the prior device. These features provide image quality with excellent image uniformity and MTF, with very little image irregularity. Depending on the intensity of the incident light, pixel readout is routed through either the regular CCD output, or the electron multiplier. This mode of selection enables both focused and high contrast imaging in a variety of light applications, like direct sunlight, or low light night scenes.

Framos notes that, “ON Semiconductor is the only sensor producer to offer Interline Transfer EMCCD technology and sensor sensitivity ranging from 0.002 lux in the sub-lux range to direct sunlight at 10,000 lux. With very good image quality, ON Semiconductors KAE-04471 provides an excellent low light performance where other sensors reach their limits.” High contrast and low readout noise are features that also benefit microscopy, fluoroscopy, ophthalmology, and dermatology. The KAE-04471 sensor is available in both monochrome and Bayer colour versions.

Framos; www.framos.com