In order to compare the bullet automatically

the 3D texture information acquisition system of the bullet based on the structure light is established. Because the central axis and acquisition system axis

y

is difficult to completely overlap when we acquired three-dimensional information of bullets

so the corresponding coordinate rotation is need

especially when the bullet was deformed

it is unable to utilize the information that the bullet is approximate a cylindrical

this is very difficult for bullet extraction. Therefore this paper used the Gaussian approximation filter to get the mean line determined by Gauss filter

and then 3-D bullet information subtracts from mean line determined by Gauss filter

the bullet texture was extracted. Twelve order IIR digital Gauss filter is designed using the impulse response method

its amplitude transmission characteristic deviation is less than 1.38%

significantly better than the ISO11562 specified 2.5%. This method makes the bullet extraction process more simply

and the extraction result is more accurately

improving the accuracy of bullet comparison obviously.