A photon detection system for single photon detection, comprising: a) a layer of photosensitive material; b) an N x M array of photo-detector diodes arranged in said layer of photosensitive material; each of said photo-detector diodes having a bias potential interface (V bias) and a diode output interface, said bias potential interface of each photo-detector diode being connected to a bias potential (V bias); c) an N x M array of high gain, low noise readout unit cells, one readout unit cell for each photo-detector diode; and d) each readout unit cell comprising: d1) an input interface connecting said diode output interface to a high-gain charge-to-voltage amplifier; d2) said high-gain charge-to-voltage amplifier being connected to a shaper; d3) said shaper being connected to at least a first comparator and a second comparator both having fixed or controllable comparator thresholds (V thr) wherein the first comparator has a higher threshold than the second comparator; d4) at least one interpixel communication logic, receiving as input at least one of the comparator outputs of the same readout unit cell and at least one of the outputs of the comparators of at least one neighboring readout unit cell; characterized in that: d5) the physical area of the photo-detector diode is subdivided in a number of smaller sections, each one representing a virtual channel; d6) the readout unit cell connected to said photo-detector diode comprises a number of counters at least equal to the number of virtual channels; d7) the interpixel communication logic is enabled to increment the counter which corresponds to the virtual channel approximating better the photon impinging position, by evaluating at least the output of the first comparator of said readout unit cell and at least one of the outputs of the second comparators of at least one readout unit cell neighboring to the first one. a) a layer of photosensitive material; b) an N x M array of photo-detector diodes arranged in said layer of photosensitive material; each of said photo-detector diodes having a bias potential interface (V bias) and a diode output interface, said bias potential interface of each photo-detector diode being connected to a bias potential (V bias); c) an N x M array of high gain, low noise readout unit cells, one readout unit cell for each photo-detector diode; and d) each readout unit cell comprising: d1) an input interface connecting said diode output interface to a high-gain charge-to-voltage amplifier; d2) said high-gain charge-to-voltage amplifier being connected to a shaper; d3) said shaper being connected to at least a first comparator and a second comparator both having fixed or controllable comparator thresholds (V thr) wherein the first comparator has a higher threshold than the second comparator; d4) at least one interpixel communication logic, receiving as input at least one of the comparator outputs of the same readout unit cell and at least one of the outputs of the comparators of at least one neighboring readout unit cell; characterized in that: d5) the physical area of the photo-detector diode is subdivided in a number of smaller sections, each one representing a virtual channel; d6) the readout unit cell connected to said photo-detector diode comprises a number of counters at least equal to the number of virtual channels; d7) the interpixel communication logic is enabled to increment the counter which corresponds to the virtual channel approximating better the photon impinging position, by evaluating at least the output of the first comparator of said readout unit cell and at least one of the outputs of the second comparators of at least one readout unit cell neighboring to the first one. d1) an input interface connecting said diode output interface to a high-gain charge-to-voltage amplifier; d2) said high-gain charge-to-voltage amplifier being connected to a shaper; d3) said shaper being connected to at least a first comparator and a second comparator both having fixed or controllable comparator thresholds (V thr) wherein the first comparator has a higher threshold than the second comparator; d4) at least one interpixel communication logic, receiving as input at least one of the comparator outputs of the same readout unit cell and at least one of the outputs of the comparators of at least one neighboring readout unit cell; characterized in that: d5) the physical area of the photo-detector diode is subdivided in a number of smaller sections, each one representing a virtual channel; d6) the readout unit cell connected to said photo-detector diode comprises a number of counters at least equal to the number of virtual channels; d7) the interpixel communication logic is enabled to increment the counter which corresponds to the virtual channel approximating better the photon impinging position, by evaluating at least the output of the first comparator of said readout unit cell and at least one of the outputs of the second comparators of at least one readout unit cell neighboring to the first one.