Image dictionary (imgCIF) version 1.3.2

_array_intensities.linearity

Name:
'_array_intensities.linearity'

Definition:

   The intensity linearity scaling method used to convert 
   from the raw intensity to the stored element value:

    'linear' is linear.

    'offset'  means that the value defined by
    _array_intensities.offset should be added to each
     element value.

    'scaling' means that the value defined by
    _array_intensities.scaling should be multiplied with each
    element value.

    'scaling_offset' is the combination of the two previous cases,
    with the scale factor applied before the offset value.

    'sqrt_scaled' means that the square root of raw
    intensities multiplied by _array_intensities.scaling is
    calculated and stored, perhaps rounded to the nearest
    integer. Thus, linearization involves dividing the stored
    values by _array_intensities.scaling and squaring the
    result.

    'logarithmic_scaled' means that the logarithm base 10 of
    raw intensities multiplied by _array_intensities.scaling
    is calculated and stored, perhaps rounded to the nearest
    integer. Thus, linearization involves dividing the stored
    values by _array_intensities.scaling and calculating 10
    to the power of this number.

    'raw' means that the data are a set of raw values straight
    from the detector.

Type: code

Mandatory item: yes

The data value must be one of the following:

linear .

offset The value defined by _array_intensities.offset should be added to each element value.

scaling The value defined by _array_intensities.scaling should be multiplied with each element value.

scaling_offset The combination of the scaling and offset with the scale factor applied before the offset value.

sqrt_scaled The square root of raw intensities multiplied by _array_intensities.scaling is calculated and stored, perhaps rounded to the nearest integer. Thus, linearization involves dividing the stored values by _array_intensities.scaling and squaring the result.

logarithmic_scaled The logarithm base 10 of raw intensities multiplied by _array_intensities.scaling is calculated and stored, perhaps rounded to the nearest integer. Thus, linearization involves dividing the stored values by _array_intensities.scaling and calculating 10 to the power of this number.

raw The array consists of raw values to which no corrections have been applied. While the handling of the data is similar to that given for 'linear' data with no offset, the meaning of the data differs in that the number of incident photons is not necessarily linearly related to the number of counts reported. This value is intended for use either in calibration experiments or to allow for handling more complex data-fitting algorithms than are allowed for by this data item.

Category: array_intensities

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Crystallographic Information Framework

Image dictionary (imgCIF) version 1.3.2

_array_intensities.linearity

International Tables for Crystallography

Volume G: Definition and exchange of crystallographic data

Edited by S. R. Hall and B. McMahon

IUCrData