Abstract: To overcome the repeat shooting to workpieces by vision system in sorting process, an image deduplication algorithm based on time and workpieces' positions is proposed. The running time of the real-time sorting system is used as basis of each sorting module, and the predicted time that workpieces arrive at a fixed reference position is combined with its current location into a set of coordinates to uniquely identify a part. So the duplicate image information can be found and removed by comparing those coordinates periodically. At the same time, in order to improve sorting efficiency, a dynamic picking algorithm based on Newton-Raphson method is proposed. The non-linear mathematical model is established for workpiece tracking, which is solved by Newton-Raphson iteration. Finally, the proposed dynamic picking algorithm is verified by MATLAB. In prototype test the maximum sorting speed can reach 110 times per minute, mistaken-grab rate is lower than 2‰, missing-grab rate is 0, which proves that the algorithms can meet the real-time, the accuracy and the stability requirements.