Pixel readout circuit

A readout integrated circuit (ROIC), comprising:

• a pixel circuitry array (PCA) comprising a plurality of pixel circuits, each pixel circuit configured to receive an optical measurement signal from a detector of an optical detector pixel array;
• at least one electrical connection to and shared by at least two pixel circuits of said plurality of pixel circuits;
• a detection circuitry configured to detect, at said at least one electrical connection, electrical fluctuation in power consumption associated with receipt at said optical detector pixel array of a pulse of laser light;
• and
• a global timing circuitry configured to timestamp said electrical fluctuation in power consumption.

A method of imaging, the method comprising:

• acquiring a plurality of measurement signals of a field of view (FOV) using an array of optical detectors each detector producing a measurement signal of said plurality of measurement signals;
• detecting and timestamping an electrical fluctuation associated with receipt of a pulse of laser light at said array of optical detectors, where the detecting is of electrical fluctuation associated with the receipt of the pulse of laser light to the array of optical detectors and is performed at least one electrical connection to and shared by at least two optical detectors of the array of optical detectors;
• receiving an indication of timing of emission of laser light pulses towards said FOV;
• and
• determining a range between one or more component of said system and an object within said FOV reflecting at least a portion of said laser light pulses, using said timestamp and said indication of timing.