High dynamic range imaging pixels with improved readout

An imaging system may include an image sensor having an array of dual gain pixels. Each pixel may be operated using a two read method such that all signals are read in a high gain configuration in order to improve the speed or to reduce the power consumption of imaging operations. Each pixel may be operated using a two read, two analog-to-digital conversion method in which two sets of calibration data are stored. A high dynamic range (HDR) image signal may be produced for each pixel based on signals read from the pixel and on light conditions. The HDR image may be produced based on a combination of high and low gain signals and one or both of the two sets of calibration data. A system of equations may be used for generating the HDR image. The system of equations may include functions of light intensity.