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INTEGRATE: Difference between revisions
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→How does INTEGRATE treat overlaps?
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# for each reflection, the background is estimated, and the 3D profile is assembled from the pixels contributing to it. | # for each reflection, the background is estimated, and the 3D profile is assembled from the pixels contributing to it. | ||
# the average profile is formed on a grid by superimposition of strong reflections found in step 3. The signal part of the profile is defined by those gridpoints of the average profile that are above a threshold (called "CUT" in XDS.INP). | # the average profile is formed on a grid by superimposition of strong reflections found in step 3. The signal part of the profile is defined by those gridpoints of the average profile that are above a threshold (called "CUT" in XDS.INP). | ||
# not all pixels of a reflection, which would be required to assemble its full profile (whose shape is given by the average profile formed in step 4), may have been observed due to step 1. Therefore, in another pass, for each reflection, the fraction of its profile is calculated. If this fraction is less than a threshold (called "MINPK" in XDS.INP), this reflection will be discarded ("too much overlap"). If it is above MINPK, the observed intensity (from the incomplete profile) is scaled up with the inverse of the fraction. Of course this scaling-up relies on the accuracy of the average profile. | # not all pixels of a reflection, which would be required to assemble its full profile (whose shape is given by the average profile formed in step 4), may have been observed due to step 1. Therefore, in another pass, for each reflection, the observed fraction of its theoretical profile is calculated. If this fraction is less than a threshold (called "MINPK" in XDS.INP), this reflection will be discarded ("too much overlap"). If it is above MINPK, the observed intensity (from the incomplete profile) is scaled up with the inverse of the fraction. Of course this scaling-up relies on the accuracy of the average profile. | ||
Among other things, this means that: | Among other things, this means that: | ||