A time domain sampling technique for a CMOS imager enables a wide dynamic
range and flexibility by employing up to two-degrees of freedom during
such sampling. Two degrees of freedom can be achieved by making one or
both of an integration time and a reference (e.g., voltage or current)
variable during sampling. The sampling (or image capture) is implemented
by associating a time with when a pixel has a desired value relative to
the reference in response to the pixel receiving incident light. The
reference can be fixed or variable during different portions of the
sampling, and further can be programmable to implement a desired sampling
pattern for a given application.