Use the Automatic Threshold dialog box to have the thresholds in an color image set automatically.
Setting threshold values is necessary to define objects in an image for an object analysis. Phases will be defined in the image by appropriate threshold values. You can find more information on threshold values and phases here.
Opening the dialog box
You open this dialog box, via the Count and Measure tool window. Load a color image. Select the Automatic Threshold... entry, in the Threshold button's context menu. You open this menu by clicking the small arrow next to the button. Should this entry already have been selected, click the Automatic Threshold... button directly.
The dialog box's structure
The dialog box is made up of several groups. Click on one of the areas in the dialog box shown above to jump to the corresponding help topic.
(1) Setting background options
(2) Defining phases
(6) Loading, saving, and managing threshold values
See also
Carrying out an automatic image analysis
Tool Window - Count and Measure
(1) Setting background options
Note: When the threshold value calculation for a true-color image is made automatically, its intensity values will be used. The color values play no part in this. For this reason, you will achieve the same results as you would if you had previously carried out an intensity separation. Should the automatic threshold calculation not be successful, you can also determine the threshold values manually. Unlike when an automatic threshold value calculation is used, when a manual threshold value calculation is carried out, the image's color values will be used.
In the Background group, you define whether the bright or the dark image structures, or alternatively the complete image, are to be used for the automatic analysis. The term background is used in this context for all of the image structures that are not within the threshold values.
Select the Dark option if the dark image structures are to be used as background. In this case, bright image structures will be defined as a phase and will be evaluated in the automatic analysis.
Select the Bright option if the bright image structures are to be used as background.
Select the Automatic option if the classifying of the image structures as either phase or background, is to occur automatically. In this case your software evaluates the images histogram. Please note that the number of phases to be defined isn't automatically adjusted. The number of phases to be defined has to be set correctly so that the image structures can be correctly allocated to a phase.
Select the None option if no image area is to be defined as background. In this case, the complete image will be evaluated when the automatic analysis is carried out.
In image (1), you can see objects with three different gray intensity values.
In image (2), the bright image structures are the background. The rest of the image is allocated to one single phase. The phase is colored red here.
In image (3), the dark phases are defined as background. The bright phase is detected.
In image (4) no background has been chosen, all image structures are defined as phases. In this case, three phases are defined.
(2) Defining phases
Use the Phase group to define phases.
Adding phases
Click on the Add Phase 
button to create a phase.
Double click the field in the Class Name column to enter a name for the corresponding phase.
Double click the field in the Color column to open the color palette and to select a color for the corresponding phase. The phase will be displayed in the color you have assigned it, in the image window and in the histogram.
The threshold value range for the phase will be automatically calculated and shown in the Channel thresholds for phase'...' group. In the [ Min. field, the threshold value range's lower value is specified. In the Max. [ field the higher value is specified. The higher value itself no longer belongs to the threshold value range. The values will be calculated from the displayed histogram.
Deleting phases
Click the Remove Phase 
button to delete a phase. At least one phase will always be defined. It's only possible to remove a phase when two phases have been defined.
(3) Phase threshold values
The phases that have been defined can be individually selected in the Phase group. In the Channel thresholds for phase'...' group, the automatically calculated threshold values for the currently selected phase will be displayed. The current phase is emphasized with a more vibrant color in the histogram.
(4) Histogram display
The histogram shows the current image's intensity distribution. You can find more information on the histogram display here.
(5) Setting preview options
Use the Preview of phases group to display the phases in color in the image when setting the thresholds. By using the Preview you will have a direct visual control over which image areas belong to a phase and which don't. The phases are only displayed in color as long as the dialog box for setting thresholds is open.
Select the None option to have the preview switched off. None of the phases that have been defined will be displayed in the image in color.
Select the Current option to have the currently selected phase shown in its assigned color, in the image. You select a phase by clicking it in the Phase group.
Select the All option to have all of the defined phases shown in the image, in their assigned colors.
Select the Transparent option to make it possible to recognize the image structures despite the phases being displayed in color.
Even when the dialog box for setting threshold values is open, you can still use your software's zoom functions as usual. Move your mouse pointer onto the appropriate position in the image, then use the mouse wheel to zoom into or out of the image.
The default setting for the Preview of phases group, is the All option. Every time you reopen the dialog box, the All option will therefore be initially set.
(6) Loading, saving, and managing threshold values
Use these buttons to load, save or change the threshold value settings. You can save the following settings to a parameter set: The phase's name, the number of phases and the colors assigned to them.
When automatically setting threshold values, the intensity ranges belonging to the individual phases are recalculated for each image.
You will find more information on working with parameter sets here.
5610 24112014