Samsung Patents an Image Sensor That Calibrates Once for Multiple Exposure Levels

By Patentlyze Team · Updated Jul 24, 2026

Modern smartphone cameras often stitch together several exposures to nail a tricky scene, but each exposure usually demands its own calibration step, slowing things down. Samsung's new patent describes a way to do all four exposures with just one calibration pass.

How Samsung's multi-exposure sensor skips extra calibration

Imagine taking a photo of a bright window with a dark room in front of it. Your phone's camera secretly captures the scene at multiple brightness settings and combines them so nothing is blown out or pitch black. The catch is that the camera's sensor normally has to "zero itself out" before each of those captures, which takes time and can introduce tiny errors.

Samsung's patent describes an image sensor that reads a pixel four times at two different sensitivity settings but only runs that zeroing-out step once across all four reads. The sensor pairs each read with a matching reference signal (called a ramp signal) at the right sensitivity level, so the math still works out correctly without the extra calibration overhead.

The practical upside is a faster, more consistent readout. Fewer calibration passes means less time between frames and potentially less electrical noise sneaking into the final image, which matters most in low-light or high-contrast situations.

How the auto-zero and ramp signals handle four pixel reads

The patent describes an image sensor built around a pixel that outputs four sequential signals: two at a "high conversion gain" (higher sensitivity, better for dark areas) and two at a "low conversion gain" (lower sensitivity, better for bright areas). Each pair consists of a reset-level read and a signal-level read, which together let the sensor subtract out any baseline noise from the actual light data.

A ramp signal generator produces four matching reference waveforms, one per pixel read, each tuned to the correct analog gain (an amplification factor applied before the signal is digitized). The ramp signals rise at rates that correspond to either the first or second gain setting, mirroring the pixel's own sensitivity at each moment.

The key invention is the auto-zero operation. In a conventional design, the analog-to-digital converter (ADC) (the circuit that turns the analog light reading into a digital number) zeroes its internal capacitors before every comparison to cancel out offset errors. Here, the ADC performs that step only once, using whichever reset level arrives first, then carries that reference through all four comparisons:

• First reset level vs. First ramp signal
• Second reset level vs. Second ramp signal
• Second signal level vs. Third ramp signal
• First signal level vs. Fourth ramp signal

Doing it once instead of four times cuts readout time and reduces the chance of mismatch errors accumulating across the four conversion steps.

What this means for low-light and high-contrast mobile photography

For photographers, fewer calibration cycles per frame can translate to faster readout speeds and cleaner images, particularly in scenes with a very wide range of light and shadow. Camera sensors already perform high dynamic range (HDR) capture by combining multiple exposures, and any technique that tightens up the timing or reduces noise in that pipeline is worth watching.

For Samsung specifically, this is squarely in the territory of the image sensors the company sells both inside its own Galaxy phones and to other device makers. A more efficient ADC calibration scheme could appear in future generations of its ISOCELL sensors, potentially improving video frame rates or burst-shot performance without requiring larger or more power-hungry silicon.

Editorial commentary on a publicly published patent application. Not legal advice.