SPAD based indirect time of flight sensing from solid state transmitter scanning

A time of flight ranging system, comprising:

• an array of single photon avalanche diode (SPAD) pixels;
• and
• control circuitry configured to cause the array of SPAD pixels to perform steps of:
• a) integrating SPAD event data received from each SPAD pixel of a first cluster of SPAD pixels during a first illumination of a target into counters, the first cluster of SPAD pixels being a subset of the array of SPAD pixels;
• b) integrating SPAD event data received from each SPAD pixel of a second cluster of SPAD pixels during a second illumination of the target into the counters, the second cluster of SPAD pixels being a subset of the array of SPAD pixels;
• c) at a start of integration of the SPAD event data received from each SPAD pixel of the second cluster of SPAD pixels, accumulating the integrated SPAD event data that was received from each SPAD of the first cluster of SPAD pixels into a first memory;
• d) integrating SPAD event data received from each SPAD pixel of the first cluster of SPAD pixels during a third illumination of the target into the counters;
• e) at a start of integration of the SPAD event data received from each SPAD pixel of the first cluster of SPAD pixels during the third illumination of the target, accumulating the integrated SPAD event data that was received from each SPAD pixel of the second cluster of SPAD pixels during the second illumination of the target into a second memory;
• f) integrating SPAD event data received from each SPAD pixel of the second cluster of SPAD pixels during a fourth illumination of the target into the counters;
• and
• g) at a start of integration of the SPAD event data received from each SPAD pixel of the second cluster of SPAD pixels during the fourth illumination of the target, accumulating the integrated SPAD event data that was received from each SPAD pixel of the first cluster of SPAD pixels during the third illumination of the target into the first memory.