A system counts photon interactions in an array of photosensitive diodes and addresses the issue of improving position resolution. Every photo-detector diode of the array is connected to a readout unit cell containing a high-gain charge-to-voltage amplifier, a shaper, at least two comparators with independent thresholds and at least one interpixel communication logic, receiving as input signals from comparator outputs of the same readout unit cell and of the neighboring readout unit cells. This logic is then connected to at least one counter, each counter followed by a counter readout. By means of the digital interpixel communication logic and the set of comparators with different thresholds in every readout unit cell, it is possible to determine the photon hit position in the detector with a higher position resolution than the physical photo-detector size including the removal of the corner effect in pixel detectors.