Zhixin Song

We propose a pulsed laser ranging method based on a multiecho delay trigger, which improves the precision of pulsed laser ranging. A signal delay unit is used to accurately delay the pulse-echo signal. In a fixed time window, the echo delay pulse triggers the laser transmitter to generate pulsed laser light; meanwhile, the counter records several echo pulses received, and then, the actual distance can be calculated. In terms of improving the ranging precision, this method overcomes the essential of higher time resolution time-to-digital converter (TDC) chip in traditional time-of-flight (TOF) pulsed laser ranging. The method can be realized by using a field-programmable logic gate array (FPGA) chip, a delay unit, and a set of laser transmitters and receivers, which makes the system structure simple and low cost. Experimental results show that this method can achieve more accurate distance measurement and significantly reduced error, to the best of our knowledge, which improves the pulsed laser ranging from centimeter- to millimeter-order precisions. We believe that this method has a promising application prospect in the field of high-precision pulsed laser ranging of fixed targets.

We propose a method that realizes laser ranging and communication at the same time based on dual-pulse interval modulation (DPIM). The transmission of binary data bits in the communication process is realized by sending two laser pulses continuously, and the time interval between the dual pulse is used to characterize the value of this bit (0 or 1). Meanwhile, the echo signal received by the communication transmitter is also a dual pulse signal, which enables laser ranging by the time-of-flight (TOF) principle. This method can effectively improve the reliability of system communication. Furthermore, the system structure is rather simple, including one piece of field programable logic gate array (FPGA) chip, one piece of time-to-digital converter (TDC) chip, and a transmitting and receiving circuits. The experimental results show that this method and system can achieve effective and reliable transmission of 2-D images and characters at the ranging accuracy of a single laser ranging system.

Most ghost imaging reconstruction algorithms require a large measurement time to retrieve the object information clearly. But not all groups of data play a positive role in reconstructing the object image. Abandoning some redundant data can not only enhance the quality of reconstruction images but also speed up the computation process. Here, we propose a method to screen the data using two threshold values set by a proportional parameter during the sampling process. Experimental results show that the reserved data after screening can be used in several reconstruction algorithms, and the reconstruction quality is enhanced or at least remains at the same level. Meanwhile, the computing time costs are greatly reduced, and so is the data storage.