Systems and methods for dark current compensation in single photon avalanche diode imagery

A system for compensating for dark current in single photon avalanche diode (SPAD) imagery, the system comprising:

• a SPAD array comprising a plurality of SPAD pixels;
• one or more processors;
• and
• one or more hardware storage devices storing instructions that are executable by the one or more processors to configure the system to:
• capture an image frame with the SPAD array while obscuring a plurality of unexposed SPAD pixels from the plurality of SPAD pixels;
• identify a region of the image frame that corresponds to the plurality of unexposed SPAD pixels which are obscured during the capturing of the image frame to prevent photons from reaching the plurality of unexposed SPAD pixels;
• determine a dark current value based on a quantity of photons detected by the plurality of unexposed SPAD pixels during the capturing of the dark current image frame;
• and
• generate a dark current compensated image by performing a subtraction operation based on the image frame and on the dark current value, wherein the subtraction operation comprises subtracting the dark current value from one or more SPAD pixels of the plurality of SPAD pixels determined to generate dark current based on a previously performed calibration operation, while refraining from subtracting the dark current value from other SPAD pixels of the plurality of SPAD pixels that are separate from the one or more SPAD pixels.

A method for compensating for dark current in single photon avalanche diode (SPAD) imagery, the method comprising:

• capturing an image frame with a SPAD array, the SPAD array comprising a plurality of SPAD pixels;
• generating a temporally filtered image by performing a temporal filtering operation based on the image frame and at least one preceding image frame, the preceding image frame having been captured by the SPAD array at a timepoint that temporally precedes a timepoint associated with the image frame;
• obtaining a dark current image frame, the dark current image frame comprising data indicating coordinates of one or more SPAD pixels of the plurality of SPAD pixels that detect an avalanche event without detecting a corresponding photon;
• and
• generating a dark current compensated image by performing a subtraction operation on the temporally filtered image or the image frame based on the dark current image frame.