problems with an image from a laser raster

bpjackso

Hi, We've traditionally collected images in one ICP-MS file but as a series of y offset horizontal left to right laser scan lines on our NWR. Becuase of some problems we've had with our NWR stage controller stalling at the begining of random lines, and to reduce the imaging time from the laser returning to the left of the image for reach line, we decided to use the continous laser on scan (left to right, then back from right to left) to cover the image in the NWR software (in the NWR software this is a raster, whereas Iolite considers it a boustrophedon * I think*). It seemed to work OK (XY did not stall in this raster mode) but the elemental images, which we can only process in the cell space type, seem systematically distorted with one line offset a bit to the right and then the next line offset to the left as if the lasr log file coordinates and ICP-MS data are not exactly matching up.
Is this a known issue? Is there a different/correct way to handle the data from this experimental approach?

Thanks,
Brian

Bence

Hi Brian,

Yes, iolite would refer to scanning back and forth in alternating directions to be "boustrophedon".

There can be a couple of reasons the edges of the image are not lining up: it could be a rounding issue in the horizontal coordinate; it could be that the horizontal coordinates of each line are indeed offset; or it could be some other effect. If you could send us a copy the experiment to the iolite support email, I can take a look and let you know what's going on, and fix any possible issues.

You can also process this sort of image in the "From Selections" mode, by selecting the "Boustrophedon" option in the Map Style dropdown menu. If you do process the image in this way, there is a "Justify" option in the Alignment dropdown menu that will align the starts and ends of each scanline. This does do some interpolation though, so it might be better to get the CellSpace issue sorted.

Bence