User guide

Volume Tools
16-11
The average intensity of the pixels in that background volume will be
calculated and subtracted from each pixel in all standard and unknown
volumes. Any pixels inside the volumes that have the same intensity as the
average background will be reduced to zero, thereby eliminating them from
the quantitation.
If you create more than one background volume, all the pixels in those
background volumes will be used to calculate the average background.
Your background volume(s) will have default names B1, B2... etc., based on
their creation sequence. You can display/hide volume names using the
Show/Hide Volume Labels command.
Note: If the region you identified as background has a higher average intensity
value than your data object, then you will obtain a negative value for
your adjusted volume in the Volume Analysis Report. If this happens,
select a new background region that has less intensity than your data
object.
Displaying the Results of Background Subtraction
The Volume Analysis Report (section 19.5) will display both the unadjusted
volume and the volume with background subtracted (adjusted volume) of
your standards and unknowns, so you can see exactly how much intensity
was subtracted.
16.5 Volume Arrays
The Volume Array Tool on the Volume menu and toolbar can be used for
quantitating dot blots, slot blots, and other arrays.
Note: You cannot create a volume array in an image with asymmetric pixels
(i.e., different dimensions in x and y). If you are trying to create a volume
array in such an image, select Reduce File Size from the File menu and
change the image’s pixel dimensions in the pop-up dialog box.