Image recognition base ablation pattern position recall
Embodiments of the present invention exemplarily described herein relate generally to saving XYZ stage coordinates for intended laser locations as well as a kernel image of an ablation pattern placed during a scan placement process, and comparing the kernel image to a current image of the current field of view of a camera/microscope that includes the location a laser would be fired at. This comparison is used during an experimental run to correct for any built up error. More particularly, embodiments of the present invention relate to apparatuses and methods for software based image recognition to correct errors in open looped systems for positioning a sample relative to a laser in analysis systems for zircon crystal grain dating.
1. A method for positioning a laser on a sample during a laser ablation procedure comprising:
setting an ablation pattern including multiple intended laser ablation locations for a sample during a scan placement process comprising:
positioning the sample relative to a laser ablation location to said multiple intended laser ablation locations on the sample with a motion control system;
saving position coordinates for each of said multiple intended laser ablation locations, and;
saving a kernel image of the sample at each of said multiple intended laser ablation locations; and
for all the multiple intended laser ablation locations:
positioning the laser ablation location relative to the sample to a current position based on the saved coordinates of a chosen one of the multiple intended laser ablation locations with a saved kernel image;
comparing a current image of the sample at the current position with the saved kernel image of the sample for the chosen intended laser ablation location;
determining a position error based on the comparison;
if the position error is not within a window of acceptability, then applying an offset movement of the laser ablation location relative to the sample with the motion control system based on the position error to correct for the position error and repeat the comparing and determining steps; and
if the position error is within the window of acceptability, then fire a laser beam upon the sample at the laser ablation location.
2. The method of claim 1 , wherein the motion control system is an open-loop system; and
wherein, in said positioning the laser ablation location relative to the sample to a current position, the current position is an open-loop assumed correct position.
3. The method of claim 1 , wherein the kernel image and the current image are taken with a camera that is fixed relative to the laser ablation location.
4. The method of claim 1 , wherein the step of positioning the laser ablation location relative to the sample to a current position occurs after sampling a reference blank.
5. The method of claim 1 , wherein the step of saving a kernel image for each of said multiple intended laser ablation locations further includes saving at least one of lighting levels, zoom levels, or camera properties used when capturing the kernel image.
6. The method of claim 1 , including flowing a carrier gas over the sample, wherein said laser beam causes material of the sample to be suspended in the carrier gas, and analyzing the material suspended in the carrier gas.
7. The method of claim 6 , wherein the sample comprises zircon.