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Sensor Technology
Q: What is it?
A: It is the next generation image sensor technology that provides greater imaging performance. It combines the best performance features of a CCD with the benefits of CMOS. For a better understanding of the technology, see below;
Your image starts at the pixel.
The better the pixel, the better the image.
The OLD WAY, CMOS
APS Sensors.
Forget CMOS Active Pixel Sensors,
with their complex amplifier per pixel designs.
Complex sensor designs complicate your image – too much noise, not
enough sensitivity, poor dynamic range, large optical format, power
hungry, ……..…
The list of ‘bad’ goes on and on.
Active Pixel Sensors use an amplifier per pixel architecture.
An amplifier can be made from a single, very large transistor or
FET, or can be made using multiple transistors. The amplifiers purpose
is to drive the image signal up the column of pixels to the readout
circuitry.
However, that amplifier, from an engineering point of view, is a very
poor one.
It does not have feedback, a built in self-control, to control its
gain or amplification.
This means that each pixel can have a different response to light,
further corrupting your image.
Along with that amplifier, each pixel has two additional transistors
that act like switches, one to select that pixel for readout, and the
other to reset the pixel to get it ready to read the next image. When
these switches turn on and off, they add more noise to your image.
The bottom line?
All that complex circuitry adds noise and blocks your image,
reducing sensitivity and dynamic range.
Figure 1 –
Simplified CMOS APS Pixel Layout showing light sensitive and non-sensitive
areas. Only the Yellow area is
light sensitive.
CMOS APS Sensors are corrupting your image.
CCDs are expensive and power hungry.
So why use them?
XtremePIX
- The NEW, BETTER WAY
What you need is simpler, clearer imaging technology.
That is why we developed XtremePIX
- A whole new way of making sensors in CMOS.
Instead of packing all that signal corrupting circuitry inside each
pixel, XtremePIX technology simplifies, reduces, and moves it outside,
away from the pixel, away from your image.
Inside the pixel is only one half of a transistor (FET).
That’s right, less than 1/6 of the circuitry of a conventional CMOS
APS type sensor. The pixel
is now wide open to collect light, and capture your image,
cleanly!
- Nearly all
of the pixel is used to capture your image
- Image
corrupting noise is nearly eliminated
- Greatly
improved sensitivity for low light imaging
- Increased
dynamic range
Why is that half a transistor still there? It is part of another unique innovation of the XtremePIX technology. It is the input node of a Distributed A/D, what we call D/AD™. D/AD converts the image to a digital signal directly, and it uses a well-engineered closed loop feedback architecture. Your image is captured cleanly. D/AD also enables selectable bit depth, up to 12 bits per pixel, improving image fidelity and color depth.
Figure 2 – Simplified XtremePIX Sensor Layout.
Yellow area is sensitive to light.
The Benefits are clear:
-
-
Greater sensitivity, excellent for low light imaging
-
Greater Dynamic Range
-
Enables smaller pixels for increased resolution and/or smaller optical format
BETTER IMAGES!
