Originally posted by biz-engineer Conceptually at least it is possible to have a CMOS image sensor work like a film negative, like for example pre-charging all sense cells to maximum level at sensor reset and have the capacitance discharge when exposed to light. There are probably some reasons why camera sensors aren't "non-linear negative sensors" like film negatives, could be poor quantum efficiency / base ISO value and leakage issues for long exposures.
You might want to check out this article on how image sensors actually work:
Imaging Electronics 101: Understanding Camera Sensors for Machine Vision Applications
Your idea of pre-charge isn't in line with how the devices work - but something similar to your idea helps fight Residual Bulk Image (RBI).
Unlike film negatives, CCD/CMOS APS devices are linear because some number of photons X converted to some number of electronics Y (resulting in a e- charge in a CCD, or voltage in CMOS APS) - that's the Quantum Efficiency Y/X. Once you hit the Full Well Depth of the pixel (how many total electrons it wll hold), it won't hold any more - and may bloom into neighbouring pixels, or just tosses them away like extra beer spilling over the sides of a glass. The FWD is the point where it becomes non-linear. Brighter stuff just can't make the charge (or voltage) go any higher.
At the bottom end, dim images are often overwhelmed by Dark Current - electrons that kick up a fuss through thermal heating effects, this leads to glow in the image, a background level that is not pure black.
Fighting RBI:in some low-light applications like astronomy, there are LEDS placed near the sensor to flood it with near infra-red light, completely topping up the sensor before it is cleared (emptied out of charge). This ensures any ghost images caused by charge that is remaining gets evened out, as all pixels eventually drain to near-zero (actually their bias/dark current level).