The invention relates to a photon detecting 3D imaging sensor device for detecting a distance information for pixels in an image, comprising: - an array of detector units, wherein each detector unit is configured to receive a light signal pulse and to provide a detection signal pulse on receipt of a light signal pulse; - a pulse selection unit including a decision tree with one or more stages, wherein each of the stages has one or more decision makers which are cascaded to propagate the earliest detection signal pulse of one of a respective detector unit as a timing signal; - a time-to-digital converter configured to receive the timing signal and to provide a time stamp depending on the timing signal wherein the time stamp indicates the distance information for a pixel of the image.