By default displayed images are automatically scaled to display the complete range of intensities in the displayed region. This behaviour can be modified using Z-SCALE. Five Z-axis (intensity) scaling modes are available:
Depending on the scaling mode selected you may be prompted for the minimum and the maximum values to be displayed. Once set the scaling mode continues to operate on all subsequent images, until Z-SCALE is used again to change the mode. (This may lead to strange results if you forget that you have set a particular scaling range.)
The Automatic ``Weak Diffraction peak'' scaling option allows an adaptive scaling option which is designed to automatically adjust the scaling range to display effectively weak data peaks. This is done by examining the image statistics in the the centre of the image, or all of the image if the ROI is small. From the average, the standard deviation and the skewness of the distribution an appropriate display range is calculated. This option is still under development to find the best scaling under a wide variety of circumstances.
As well as automatic or manual selection of the intensity scaling range, the intensity scale may be either linear or logarithmic (V7.25). The user is prompted for logarithmic scaling (the default is ``NO''). e.g.
LOGARITHMIC IMAGE SCALING [NO]:? The false colour image display may use either linear intensity scaling (the default), or logarithmic intensity scaling. Here you can choose which to use. Enter ``YES'' for logarithmic scaling, ``NO'' for linear scaling. LOGARITHMIC IMAGE SCALING [NO]:
If logarithmic scaling is used, and the linear scale includes 0.0 or negative numbers, automatic thresholding is applied to avoid the problem of very small numbers. The threshold level depends of the scale being displayed.