Imaging sensor and imaging apparatus
The processing unit of the sensor includes a time counter and pixel counters. The number of lines is reduced by sharing output lines with the pixel counters and the time counter. In addition, readout time is reduced by transposing an output sequence of pixel count values and time count values across Bayer units depending on a state of saturation of a pixel.
1. An apparatus which comprises a sensor in which a pixel including a conversion unit configured to detect incidence of a photon and a pulse processing unit configured to process a pulse generated by photon detection in the conversion unit are arranged two-dimensionally, the apparatus comprising:
at least one processor; and
a memory coupled to the at least one processor, the memory having instructions that, when executed by the processor, causes the at least one processor to function as:
a time counter configured to count a clock from a start of exposure in one frame;
pixel counters each configured to count the number of pulses from the start of exposure in the one frame; and
an image processing unit configured to calculate respective pixel values based on the count values of the time counters and the pixel counters,
wherein the time counter and the pixel counters share an output line, and exclusively output count values, respectively.
2. The apparatus according to claim 1 , wherein
the pulse processing unit outputs the count values of the time counter and the pixel counters in a time-divisional fashion at each cycle of assertion of a select line to select the pixels.
3. The apparatus according to claim 2 , wherein
the pulse processing unit further includes a determination unit configured to determine whether or not the count value of any of the pixel counters reaches a threshold within the one frame, and
the pulse processing unit outputs the count value of the time counter to the output line instead of the count value of the pixel counter determined to reach the threshold, and transposes the cycle to output the count value of the time counter.
4. The apparatus according to claim 3 , wherein the pulse processing unit skips the cycle to output the count value of the time counter in a case where there are no pixel counters determined to reach the threshold.
5. The apparatus according to claim 3 , wherein
the pixels are formed from four pixels of RGBW, and
in the pulse processing unit, two pixel counters out of the four pixel counters of the pulse processing unit corresponding to the four pixels share a first output line and the remaining two pixel counters share a second output line, and output from the one time counter corresponding to the four pixels is coupled to the first and second output lines in a split manner.
6. The apparatus according to claim 5 , wherein
the determination unit determines whether or not the pixel counter of the W pixel reaches the threshold, and
the pulse processing unit outputs a count value of the pixel counter of the W pixel in advance.
7. The apparatus according to claim 5 , wherein
the four pixels are defined as one Bayer unit, and
the pulse processing units in two adjacent Bayer units transpose cycles to output the count values of the time counters and the pixel counters.
8. The apparatus according to claim 7 , wherein
the pulse processing units in the adjacent Bayer units transpose the cycles to output the count values of the time counters and the pixel counters depending on whether or not the pixel counter of one of the W pixels reaches the threshold.
9. The apparatus according to claim 3 , wherein
the pixels are formed from four pixels of RGGB, and
in the pulse processing unit, two pixel counters out of the four pixel counters of the pulse processing unit corresponding to the four pixels share a first output line and the remaining two pixel counters share a second output line, and output from the one time counter of the pulse processing unit corresponding to the four pixels is coupled to the first and second output lines in a split manner.
10. The apparatus according to claim 9 , wherein the determination unit determines whether or not the count value of any of the four pixel counters reaches the threshold.