Image sensors having high dynamic range functionalities

A method of operating a rolling shutter image sensor pixel that includes a photodiode, a transfer transistor, readout circuitry, and a charge storage region, the method comprising:

• with the photodiode, generating a first image signal in response to light during a first exposure period;
• using the transfer transistor, transferring the first image signal to the charge storage region;
• using the readout circuitry, performing readout operations on the first image signal during a readout cycle;
• and
• while performing readout operations on the first image signal, generating a second image signal in response to light during a second exposure period, wherein the second image signal is read out during the readout cycle.

A system, comprising:

• a central processing unit;
• memory;
• a lens;
• input-output circuitry;
• and
• a rolling shutter image pixel, wherein the rolling shutter image pixel comprises:
• a photosensitive region that is configured to generate image signals in response to light during a first discontinuous integration period, wherein the first discontinuous integration period comprises a plurality of continuous integration periods during each of which a corresponding image signal is generated by the photosensitive region and wherein the photosensitive region is configured to generate a second image signal in response to light during a second continuous integration period;
• a floating diffusion region that is configured to sum the corresponding image signals from the plurality of continuous integration periods to generate a first image signal, wherein the first and second image signals are sampled from the rolling shutter image pixel during a single readout sequence;
• and
• readout circuitry that performs readout operations on the first image signal while the photosensitive region generates the second image signal and that subsequently performs readout operations on the second image signal during the single readout sequence.