Solid state imaging device, signal processing method of solid-state imaging device and imaging apparatus capable of removing vertical smears

A signal processing method of a solid-state imaging device, the solid-state imaging device comprising (1) a pixel array unit in which unit pixels including photoelectric conversion elements are arranged in a matrix the pixel array unit configured to generate a first signal at the time of reset of a unit pixel and a second signal corresponding to electric charges obtained by the photoelectric conversion in the photoelectric conversion element of the pixel unit, and output the first and second signals to a signal line as a pixel signal, (2) a signal processing unit having a variable gain amplifier configured to amplify various signals including a plurality of gains each gain set in accordance with the strength of the pixel signal, and an analog/digital converter configured to convert amplified signals into digitized signals, the method comprising the steps of:

• supplying a reference signal to the signal line;
• passing the reference signal through the signal processing unit and storing a digitized reference signal in a plurality of memory units such that the plurality of memory units respectively store the digitized reference signal for each gain from the variable gain amplifier;
• passing a pixel signal through the signal processing unit;
• and
• subtracting the digitized reference signal for each gain stored in the plurality of memory units from the digitized pixel signal that has passed through the signal processing unit such that the vertical smear noise component of the digitized pixel signal is removed.

An imaging apparatus comprising:

• a pixel array unit in which unit pixels including photoelectric conversion elements are arranged in a matrix, the pixel array unit configured (1) to generate a first signal at the time of reset of a unit pixel and a second signal corresponding to electric charges obtained by the photoelectric conversion in the photoelectric conversion element of the pixel unit and (2) output the pixel signal to a signal line;
• a signal processing unit including (1) a variable gain amplifier configured to amplify various signals at a plurality of gains, each gain set in accordance with the strength of the pixel signal and (2) an analog/digital converter configured to convert amplified signals into digitized signals;
• a signal supply unit configured to supply a reference signal to the signal line;
• a plurality of memory units configured to store the digitized reference signal after the digitized reference signal has passed through the signal processing unit such that the plurality of memory units store a reference signal for each gain from the variable gain amplifier;
• and
• a correction unit configured to subtract the digitized reference signal for each gain stored in the plurality of memory units from the digitized pixel signal after the digitized pixel signal has passed through the signal processing unit such that the vertical smear noise component of the digitized pixel signal is removed.