A method of counting and subdivision of Moiré fringe is provided to implement precision displacement measurement. The counting and subdivision of the fringe are completed in DSP (digital signal processor)

so it can solve the problem that counting circuit can't match the subdivision system properly by logical judgement. Because of utilizing high-speed optoelectronic converter and flash sample technique

the system can process Moiré signal with wide frequency range. The example demonstrates in the paper can count and divide signals from DC to 1MHz

i.e. If the optical sensitivity of the signal is 1 fringe per μm

the fastest measuring speed can reach 1000mm/s

and the highest resolution is in nm level. The experimental result shows that the software solution has high accuracy and sound reliability.