High delay precision based on dynamic phase-shift for range-gated laser imaging technology

The range-gated laser imaging technology has become a useful technique in many applications in recent years. In order to expand the range of imaging detection and improve the measurement range resolution of the imaging system, we used circular step advance delay sequence for the synchronous control. And we developed a method of using dynamic phase-shift technique in FPGA to improve the precision of the delay in the time sequence, which can make the precision of the delay stepper between the two adjacent frames less than global clock period of the FPGA and approach the limit of FPGA’s operating frequency. That is to say, it can equivalently increase the clock frequency. Then we can effectively improve measurement range resolution of the imaging system. In this paper, we have studied how dynamic phase-shift technique can be equivalent to higher clock frequency and performed some experiments. We presented the structure of dynamic phase-shift technique used to improve the precision of delay in the synchronization control time sequence. And the simulation and experimental results are showed in this paper. The results demonstrate that using dynamic phase-shift technique in FPGA can make the precision of the delay between the ICCD’s trigger pulse and the laser’s trigger pulse reach 1ns, which means the resolution of measurement range can be 0.15m theoretically. The timing control signal with dynamic phase-shift technique designed in this paper can be widely used in range-gated imaging because of its high timing control precision and flexible parameter setting.