Several possible enhancements are provided. The default is ``Linear'' which is a simple contrast stretch. The darkest pixel in the source image is forced to black, the lightest to white, and all the values in between are stretched proportionally.
The ``Root'' enhancement is similar to ``Linear'' except that the values between the minimum and maximum are stretched in such a way that they fit on a square root curve, instead of a straight line as with ``Linear''.
The ``Equal'' enhancement modifies the brightness of pixels with the intention of having a similar number of pixels at each level of brightness. This is an equalization of the output image histogram.
The linear, root, and equalization enhancements are computed based on the area of the image that is currently displayed on the screen. If you zoom in on a dark subarea of the image, and are using a linear enhancement, the window will adapt by attempting to lighten up the dark area. This dynamic, or ``Tracking'' enhancement can be disconcerting. To force the window to continue using the current enhancement without tracking, select ``Hold'' on the option menu. This effectively freezes the current LUT until another option is selected.
The ``None'' option displays the real satellite data, without any enhancement.
Understanding the details of the different enhancements is not as important as experimenting to find the one that brings out the interesting features on the image with which you are working.