Watershed Threshold

Menu:   Processing > Threshold ->Automatic->Watershed

Script   threshWater

Use this command to automatically segment the image into several phases by searching for minimums in an image histogram. The function treats the histogram as a topographic relief and finds the deepest "valleys" in it. The located levels of intensity are used as thresholds to segment the image into selected number of phases. Before the minimum search procedure is applied, the histogram is smoothed using a Filter selected.

If you choose this command, the following options will become available:

Input

Displays the input image frame number. If you want to apply thresholding to another image, type or select the corresponding value.

Output

Displays the number of the frame in which the segmented multiphase image will be created. Depending on the Preferences. ImageWarp will set it either to the first available value or to the Input frame number. Type or select another value if you want the output image to be created in a different frame.

Channel

Lets you select the color channel that will be used for the histogram analysis.

Click Luminance to separate objects of interests based on the intensity distribution.

Click Hue to separate objects of interests based on the color pigment distribution.

Click Saturation to separate objects of interests based on the color saturation distribution.

This option is disregarded for grayscale images.

Phases

Displays the number of phases into which the image will be segmented. Type or select a different number if you want to segment the image into a different number of phases.

Filter

Lets you select the type of a filter used to smooth the image histogram.

Click Open to apply the morphological Open operator to the histogram.

Click Median to apply the median filter to the histogram

Width

Lets you adjust the width of the window for smoothing the histogram.

Invert

Select this check box to invert the operation. If this box is unchecked, the pixels whose values are equal or above the minimum calculated threshold will be treated as foreground ones, while the pixels with values below the will be treated as background ones. If this box is checked, the pixels whose values are equal or above the maximum calculated threshold will be treated as background ones, while the pixels with values below the will be treated as foreground ones.

Ignore B&W

Select this check box to exclude saturated black and white pixels (minimum and maximum pixel values for the given type of image) from the calculation.