Solid-state imaging device and camera system with a reset-level variation correction function

A solid-state imaging device comprising:

• a plurality of pixels two-dimensionally arrayed and configured to perform photoelectric conversion;
• a readout section configured to read out signals from the plurality of pixels one read-out unit at a time, each read-out unit comprising N>1 of the plurality of pixels, the readout section including N analog-to-digital converters (ADCs) for performing analog-to-digital conversion (A-D conversion) on the signals based on a ramp voltage having a predetermined A-D conversion ranges;
• and
• a signal processing system configured to set a baseline offset of the ramp voltage;
• wherein the readout section and the signal processing section are configured to automatically determine an optimal baseline offset of the ramp voltage based on a test value and to iteratively adjust the test value by, in each iteration:
• obtaining digital reset values for a group of the plurality of pixels by performing A-D conversion of pixel reset levels of the group using a baseline offset of the ramp voltage that is based on the first value, the reset signals being signals read out from the group incident to a reset operation,
• obtaining an average reset value for the iteration by averaging the digital reset values of the group,
• comparing the average reset value for the iteration to a predetermined target value, and
• automatically adjusting the test value in a direction that would cause the average reset value of a next iteration to approach the predetermined target value.