Image capture apparatus and control method thereof
AssigneeCanon Kabushiki Kaisha
InventorMakoto Ise
Life of this patent
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Abstract
An image capture apparatus has an A/D converter that compares a pixel signal read out from a pixel having a photoelectric conversion element with a reference signal whose voltage changes over time, and obtains, as an A/D conversion result of the pixel signal, a digital value corresponding to a time required for a magnitude relationship between the pixel signal and the reference signal to change. The A/D converter determines a level of the pixel signal using a threshold value, makes a change rate of the voltage of the reference signal different depending on a determination result, and changes the threshold value according to a signal expansion amount of the pixel signal after A/D conversion.
Claims8
An image capture apparatus comprising:
- an A/D converter which compares a pixel signal, which is read out from a pixel having a photoelectric conversion element, with a reference signal whose voltage changes over time, and obtain, as an A/D conversion result of the pixel signal, a digital value corresponding to a time required for a magnitude relationship between the pixel signal and the reference signal to change,
- wherein the A/D converter determines a level of the pixel signal using a threshold value, makes a change rate of the voltage of the reference signal different depending on a determination result, and changes the threshold value according to a signal expansion amount of the pixel signal after A/D conversion.
A control method of an image capture apparatus having an A/D converter which compares a pixel signal read out from a pixel having a photoelectric conversion element with a reference signal whose voltage changes over time, and obtain, as an A/D conversion result of the pixel signal, a digital value corresponding to a time required for a magnitude relationship between the pixel signal and the reference signal to change, the control method comprising:
- determining a level of the pixel signal using a threshold value;
- making a change rate of the voltage of the reference signal different depending on a determination result;
- and
- changing the threshold value according to a signal expansion amount of the pixel signal after A/D conversion.
Dependencies are inferred from the claim text.