Imaging sensor, imaging apparatus, and imaging method
AssigneeCanon Kabushiki Kaisha
InventorKenzo Tojima
Life of this patent
Estimating the term…
Abstract
In a case where illuminance is high, an error between the number of photons per frame calculated from time information and the number of photons and the actually expected number of photons per frame is reduced. In a time counter that counts a clock from the start of exposure in one frame, one-count time in the clock is switched depending on the illuminance. In a case where a pixel counter is saturated within a period of one frame, the illuminance is determined to be high, and a high-illuminance clock in which one-count time is set more minutely in the first half of one frame is used to count. In a case where the illuminance is not determined to be high, a normal clock is used to count.
Claims12
A sensor in which a pixel including a conversion unit configured to detect incidence of a photon and a processing unit configured to process a pulse generated by photon detection in the conversion unit are arranged two-dimensionally, the sensor comprising:
- a time counter configured to count a clock from a start of exposure in one frame;
- a pixel counter configured to count a number of pulses from the start of exposure in the one frame;
- at least one processor;
- a memory coupled to the at least one processor storing instructions that, when executed by the at least on processor, cause the at least one processor to function as:
- a determination unit configured to determine whether a counter value of the pixel counter reaches a threshold within the one frame;
- and
- a selector configured to switch the clock according to a result of determination by the determination unit,
- wherein the clock includes a first clock selected by the selector by determining that the illuminance is high and a second clock selected by the selector by determining that the illuminance is low,
- wherein the determination unit comprises:
- a detection circuit configured to detect that the pixel counter reaches the threshold;
- and
- a comparison circuit configured to compare a detection timing at which the detection circuit detects that the threshold is reached with a reception timing of a control signal supplied from a generation unit,
- wherein in a case where the detection timing is earlier than the reception timing, the illuminance is determined to be high, and in a case where the detection timing is equal to or later than the reception timing and in a case where the detection circuit does not detect that the threshold is reached, the illuminance is determined to be low, and
- wherein one-count time of the first clock is set more minutely in a first half of the one frame than one-count time of the second clock.
A method in a sensor in which a pixel including a conversion unit configured to detect incidence of a photon and a processing unit configured to process a pulse generated by photon detection in the conversion unit are arranged two-dimensionally, the method comprising:
- counting a clock by a time counter from a start of exposure in one frame;
- counting a number of pulses by a pixel counter from the start of exposure in the one frame;
- determining whether a count value of the pixel counter reaches a threshold within the one frame;
- and
- switching the clock supplied to the time counter in a case where it is determined that the threshold is reached,
- wherein the clock includes a first clock selected by determining that the illuminance is high and a second clock by determining that the illuminance is low, and
- wherein the determining comprises:
- detecting that the pixel counter reaches the threshold;
- and
- comparing a detection timing at which the detecting detects that the threshold is reached with a reception timing of a control signal supplied from a generating,
- wherein in a case where the detection timing is earlier than the reception timing, the illuminance is determined to be high, and in a case where the detection timing is equal to or later than the reception timing and in a case where the detecting does not detect that the threshold is reached, the illuminance is determined to be low, and
- wherein one-count time of the first clock is set more minutely in a first half of the one frame than one-count time of the second clock.
Dependencies are inferred from the claim text.