GC Image User Forum

I would like to have a detailed description of the following parameters: "center and half width" of both scale and translation search window.
If I want to make the search window smaller which parameters do I have to change?
What is the meaning of the deafault parameters? If the distances are expressed in pixel dimensions (as stated in gc image user guide) how can I define the "optimal search window" without expressing the thresholds in time unit (sec.)?

Thanks

Some quick answers:

lnicolot wrote:a detailed description of the following parameters: "center and half width" of both scale and translation search window.

As stated in the user's guide, "The template matching algorithm searches for a translation (i.e., horizontal and vertical shift) and scale (i.e. , horizontal and vertical resizing) of the template that aligns it with target peaks....The parameters are the center, half-width, and half-height of the translation search window; the center, half-width, and half-height of the scale search window".

lnicolot wrote:If I want to make the search window smaller which parameters do I have to change?

Usually changing Distance Thresholds is the easiest way to achieve this. Also, you could change the half width, which is not recommended for inexperienced users because of the complexity of the matching algorithm.

lnicolot wrote:What is the meaning of the deafault parameters?

The default parameters are picked for example chromatograms distributed with the software. Usually you will need to adjust them especially distance thresholds for your chromatograms.

lnicolot wrote:If the distances are expressed in pixel dimensions (as stated in gc image user guide) how can I define the "optimal search window" without expressing the thresholds in time unit (sec.)?

COL I Pixel = COL I Time / Modulation Period
COL II Pixel = COL II Time * Sampling Rate

Thank you very much for your answer!