Two image sensors with night vision for automotive ADAS

Melexis and Sony have launched night seeing capable image sensors for automotive driver assistance systems. The image sensors from both Melexis and Sony feature closely matching specs with sensitivity down to 0.005 lux (moonless night).

The MLX75421 Blackbird image sensor features on-chip functional safety (ASIL) support functions. The suggested applications of MLX75421 includes automatic emergency braking (AEB), electronic mirrors/camera monitor systems (CMS) and autonomous evasive steering. MLX75421 can also be used for surround/rear view systems with object detection functions. The MLX75421 Blackbird generates an embedded ‘frame valid’ flag for every frame based on intensive run-time self-testing.

Supporting a resolution of 1344x1008 pixels, the MLX75421 Blackbird has a 1/3” optical format and provides up to 125dB of HDR inside every frame with frame rate of 45fps and 60fps can be achieved when capturing image data from 800 rows. MLX75421 is compatible with 720p applications. The device runs fully automatically in HDR mode without the need for a companion chip.

On noise performance MLX75421 features dark leakage of less than 5 electrons/s at 25°C and dark temporal noise of less than 4.4 electrons for a 1/30s exposure time. MLX75421 operate over a wide operating temperature range of -40°C to +115°C.

The MLX75421 is available in monochrome, RCCC, color RGBG and color RGBC versions. Volume production to start in early 2015.

Sony's new automotive CMOS image sensor IMX224MQV sensor is developed using a technology with low level of sensitivity of 2,350 mV (standard F5.6). IMX224MQV is ISO/TS 16949 certified which is a requirement in the automotive industry.

Sony has used photodiodes to effectively convert photons into electrons and says it has installed circuit's to improve the conversion efficiency of those electrons into voltage. Sony has also integrated programmable gain amplifier which can amplify very low level electrical signals up to 72 DB.

Sony says "This image sensor also supports a WDR (Wide Range Dynamic) system that allows for extended exposure time, which, when compared to conventional multi-exposure WDR systems, makes possible improved image quality in low light conditions when combined with a compatible ISP (Image Signal Processor)"

Most of the cameras shooting in the night use infrared, even this CMOS image sensor can sense near infrared light outside the visual spectrum provided there is a near infrared irradiating LED.