Converts an image to a binary image by converting all pixels within user-selected threshold values to red and those outside to white.
The dialog box displays a histogram of gray levels.
In the histogram you drag the red lines to the required threshold values.
Usually, the lower threshold value line will be left at zero.
All gray levels within the threshold values will become red (indicating an object), those outside white (indicating background).
Click Preview to judge the results.
Click OK to proceed.