Signal processing apparatus and signal processing method, and image capturing apparatus

An image capturing apparatus comprising:

• an image sensor;
• an analog-digital converter that converts an analog signal to a digital signal using a plurality of reference signals having different slopes from each other;
• a supply unit that supplies analog signals of a plurality of predetermined different output levels;
• and
• a calculation unit that calculates a slope ratio and an offset amount between the plurality of different slopes for correcting a digital signal obtained by the analog-digital converter by converting an analog signal output from a pixel section of the image sensor based on a plurality of digital signals respectively obtained by converting the analog signals of the plurality of different output levels using the plurality of reference signals,
• wherein, in a case where the conversion is performed using a reference signal with a steeper slope, the supply unit supplies to the analog-digital converter at least one high level analog signal whose level is higher than a case where the conversion is performed using a reference signal with a gentler slope, and
• the calculation unit further uses a digital signal obtained by converting the high level analog signal when calculating the slope ratio.

A signal processing method, comprising:

• supplying analog signals of a plurality of predetermined different output levels to an analog-digital converter;
• converting the analog signals of a plurality of predetermined different output levels to digital signals using a plurality of reference signals having different slopes from each other by the analog-digital converter;
• and
• calculating a slope ratio and an offset amount between the plurality of different slopes for correcting a digital signal obtained by the analog-digital converter by converting an analog signal output from a pixel section of an image sensor based on the plurality of digital signals,
• wherein, in supplying the analog signals, in a case where the conversion is performed using a reference signal with a steeper slope, at least one high level analog signal whose level is higher than a case where the conversion is performed using a reference signal with a gentler slope is supplied to the analog-digital converter, and
• a digital signal obtained by converting the high level analog signal is used when calculating the slope ratio.