DaVinci CMOS vs. other new CMOS

DaVinci CMOS imagers are better than other new CMOS  tehcnologies due to the following issues:

 

Single True 14-bit A/D

DaVinci CMOS cameras use a single true 14-bit A/D converter which means that the camera is linear over the entire dynamic range of the imager for every pixel. Other CMOS technologies typically stitch two different A/Ds operating in high and low gain modes to yield high sensitivity and low readnoise for small signals while maintaining a wide dynamic range for large signals. Due to the variablity in voltage offset and gain in every CMOS imager pixel, the crossover points between the A/Ds cannot be perfectly matched resulting in a non-monotnic response in some pixels. The variability in gain also means that the responsivity of the imager cannot always be the same for large and small signals within the same pixel.

 

MTF degradation with microlenses

The QE of CMOS imagers can be effectively increased with the use of microlenses to direct photons to the light-sensitive areas of each pixel. Microlenses can only increase the peak QE to 65 or 70%, but distorts the image while doing so. Microlenses inevitably have interfaces between them where the behavior of photons is uncertain due to the tolerance in manufacturing. Even worse, on-axis photons exhibit a different QE from off-axis photons. DaVinci CMOS imagers do not use microlenses are are not subject to this kind of optical distorsion. DaVinci Low Noise CMOS sensors exhibit a peak QE of 65%, even without microlenses.

 

Image Proccessing Distortions

DaVinci CMOS Imagers do not require extensive image processing to yield scientific images. As with all CMOS imagers, each pixel has its own voltage offset and it is necessary to subtract a bias frame from readout frames to give the pixels the same baseline offset. However, the pixel response is very uniform between pixels and gain calibration is typically unnecessary. Other CMOS tehcnologies are subject to a lot of electronic processing, including spike suppression to obtain a visually acceptable image. Due to the relatively artifact-free nature of DaVinci CMOS imagers, unprocessed pixel data are always available, unlike for competing CMOS imagers.