Threshold Tool

Generates bitmaps showing all the pixels above or below a
threshold. Also allows "or'ing" and "and'ing" masks.

Choose a source window for the image either by entering
a value (0 through 9) in the text area after the label
"source image" or by pushing the link button and then moving
the cursor to the desired window and pushing the left
mouse button (there should be a beep and the window
number will appear in the text area). Using the link will
also cause the type and size of the array to appear in
the text area after the "array" label. This area is not
changeable.

Choose a window for the result by entering a value (0-9)
in the text area after the label "result image". Any previous
contents will be destroyed so be careful. The loaded default
is #1.

Enter a threshold value in the text area labeled as such.
The mask is generated by pressing one of the red buttons under
the "make mask" label. The "LE" button generates a mask with 1's
for all pixels less than or equal the threshold and 0's elsewhere.
The "GE" does the opposite.

The set of radio buttons at the bottom control whether a mask is
combined with a previous mask. The top one ("display new mask
only") ignores any previous mask. The "or" button will logically
"or" the new mask with the previously stored result and the "and"
button causes a logical "and". Only one button can be set (this
is a radio button set) and the setting then affects the next
mask generated. For the first mask, the setting doesn't matter.
By using a series of thresholds and logical settings, masks showing
the pixels for any set of values can be displayed. Also, the input
window can be changed to combine threshold masks from more than one
image. If the images are not the same size, the size of the smaller
is used for the combined result. A subarea with origin at (0,0)
of the larger mask is used.

To dismiss this help message, press help (in the tool widget) again.
To dismiss both the tool and the help, press dismiss in the tool.