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Automatic Segmentation

Difference in Job Mode

The available functionality of the individual steps can differ between the wizard in Free Mode and the steps that can be added in Job Mode, e.g. the Interactive checkbox is not visible in Job Mode.

In this step you can select the segmentation method that is applied and set parameters for the segmentation of the objects that you want to measure. All the objects detected with the current settings are highlighted in the image. Note that during the setup of the analysis (via Setup Image Analysis in Free Mode), the segmentation is only performed on the area visible in the viewport. If you enter the interactive analysis or are in Job Mode, the image will be fully segmented.

Parameter

Description

Execute

Activated: This step is included when the analysis is run. Otherwise the step is skipped.

Interactive

Activated: The segmentation can be changed interactively while the analysis setting is run.

Class List

Selects the class for which you want to define the segmentation. You can specify different settings for each class.

Segmentation Method

Displays and selects a segmentation method for the currently selected class with the dropdown.

-

Explore

Opens the dialog to explore and select an available segmentation method, see Segmentation Method Selection Dialog.

The visible parameters depend on the selected segmentation method. The following parameters sections can be available:

Sharpen Section

Parameter

Description

Sharpen

Select how to improve the sharpness by enhancing contrast at fine structures and edges of the image before the threshold values are set. The following methods are available:

-

None

No sharpening algorithm is applied.

-

Delineate

Applies the Delineate method. It emphasizes edges around structures in an image, which is useful for images where the gray value range of structures differs clearly from the gray value range of the pixels around them.

-

Unsharp Masking

Applies the Unsharp Masking method.

Threshold

Only visible, if you have selected Delineate.
Sets the threshold value for edge detection. The threshold value should correspond roughly to the gray value difference between objects and the background.

Size

Only visible, if you have selected Delineate.
Sets the size of the edge detection filter, i.e. the size of image details which are enhanced. The smaller the Size value is, the finer are the details affected by the tool. The value should correspond to the size of the transition area between objects and the background.

Strength

Only visible, if you have selected Unsharp Masking.
Sets the strength of the Unsharp Masking. The higher the value selected, the greater the extent to which small structures are enhanced.

Threshold & Histogram Section

Here you can define the threshold values for the selected class in the class list.

Parameter

Description

Threshold

Sets the brightness boundaries between which pixels are considered.

Reset

Clears the upper and lower thresholds. No pixels are considered.

Undo

Undoes the last change made to the threshold values.

Redo

Restores the last undone change to the threshold values.

Color Model

Only visible if the image is a color image, see Color Model.

-

RGB

In RGB mode you can define the threshold values for the red, green and blue color channels.

-

HLS

In HLS mode you can define the threshold values for hue, saturation and lightness.

Low

Sets the lower threshold. Only pixel values above this value are considered. The range of possible values depends on the bit depth of the image.

High

Sets the upper threshold. Only pixel values below this value are considered. The range of possible values depends on the bit depth of the image.

Invert

Only pixels outside the threshold boundaries are considered, i.e. those pixels below the lower threshold and above the higher threshold.

Full Range

Sets the lower threshold to 0 and the upper threshold to the highest value (depending on bit depth). The entire range of pixel values is considered.

Histogram

In the histogram you can change the lower and upper threshold value for the activated value. Drag the lower or upper adjustment handle or shift the entire highlighted area between the lower and upper threshold value.

Click

Click in the image on the regions that you want to define as objects. The threshold values are adapted according to the pixel intensities at the clicked position in the image.

Automatic

The threshold values are determined automatically from the histogram. During setup only the part of the image displayed in the viewport is taken for the calculation of the threshold. After the automatic calculation of the threshold values you can further modify the threshold values found interactively by selecting Click for threshold value definition.

Pick Behavior

Only visible, if you have selected Click.

-

+

Enables you to expand the currently segmented regions by the gray values/colors of the objects subsequently clicked on.

-

-

Enables you to reduce the currently segmented regions by the gray values/colors of the objects subsequently clicked on.

Tolerance

Only visible, if you have selected Click.
Specifies how many additional pixel values are included in the selection based on their brightness. A higher value means that more pixel values similar to the selected one are included. A lower value means that only the exact pixel value selected is included.

Neighborhood

Only visible, if you have selected Click.
Specifies how many additional pixel values are included in the selection based on their physical proximity to the selected pixel. A higher value means that more pixels surrounding the selected pixel are included. The threshold boundaries are adapted so that all the pixel values of these neighboring pixels are included. A lower value means that the boundaries are adapted based on only the pixels directly next to the selected pixel.

Method

Only visible, if you have selected Automatic.
Selects the algorithm that is used to automatically detect the threshold boundaries. The most suitable algorithm depends on your precise requirements. The value also depends on the bit depth of the image. The following methods are available:

-

Otsu

The pixel values below the threshold are designated as background and those above the threshold as foreground. It iterates through all possible threshold values and calculates the variance of the pixel intensities of the background and foreground pixels for each value. The threshold is set at the value that minimizes both variances. This method is particularly suited to light objects on a dark background.

-

Maximum Peak

Separates background and foreground pixels at the maximum value of the histogram.

-

Iso-Data

The pixel values below the threshold are designated as background and those above the threshold as foreground. An initial threshold value is chosen, and the mean pixel intensity of the foreground and background pixels is calculated. These two mean values are averaged and the result serves as the input threshold for the next calculation. The process is repeated until the threshold value no longer changes.

-

Triangle Threshold

The algorithm constructs a line between the peak of the highest frequency pixel intensity and the lowest pixel intensity. The distance between the line and the histogram is computed for all values along the line. The pixel intensity where the line is longest is used as the threshold. This method is particularly suited when the foreground pixels only have a weak peak in the histogram.

-

Three Sigma Threshold

Calculates the pixel value that occurs most frequently. The standard deviation of the values in the peak is calculated. The threshold is set to the pixel intensity that is the sum of the average peak value and three times the standard deviation.

Color Model

RGB

Here you can set the RGB channel threshold values.

Parameter

Description


Red

Activates the red channel in the Expander Histogram.


Green

Activates the green channel in the Expander Histogram.


Blue

Activates the blue channel in the Expander Histogram.

HLS

Here you can set the hue, lightness and saturation threshold values.

Parameter

Description


Hue

Activates the hue in the Expander Histogram.


Lightness

Activates the lightness in the Expander Histogram.


Saturation

Activates the saturation in the Expander Histogram.

Variance Section

This section is only visible if Variance-Based Thresholding is selected.

Parameter

Description

Kernel Size

Sets the kernel size used to calculate the variance value of one pixel with its neighboring pixels.

Variance

Defines the lower and upper threshold for the variance.

Model Section

This section is only visible if AI Semantic Segmentation or AI Instance Segmentation is selected.

Parameter

Description

Model Name

Displays the name of the currently selected model.

Select Model

Opens the dialog to select a segmentation model. Note that you can only use models trained on a single channel.

Model Version

Only visible if AI Instance Segmentation is selected.
Displays the currently selected model version.

Model Class

Displays the name of the currently used model class.

Reset

Resets/Deletes the selected model.

Min. Confidence

Sets the minimum value (in %) for the confidence that a certain pixel belongs to the segmented class. The default value is 51.

Select Model Dialog

Parameter

Description

Model Name

Selects a model.
Only models trained on one channel images are shown here because only those can be used to segment a specific class assigned to a specific channel.

Model Class

Selects the model class.

Model Version

Only visible for AI Instance Segmentation.
Selects the version of the model.

OK

Selects the respective model.

Cancel

Cancels the model selection and closes the dialog.

Subtract BG Section

Parameter

Description

Subtract BG

Only visible if Segmentation with Background Subtraction is selected.
Selects which kind of background subtraction is performed.

-

None

No background subtraction is performed.

-

Rolling ball

The rolling ball background subtraction is performed.

Object Size & Hole Section

Parameter

Description

Min. Object Size

Sets the minimum size in pixels that an object must have in order to be segmented.

Min. Hole Size

Sets the minimum size in pixels that a hole must have in order to be recognized for segmentation. This input is synchronized with the input for Min. Object Size, which must not be smaller than Min. Hole Size.

Fill all Holes

Specifies how holes in detected objects are treated.

On

Fills holes in segmented objects ().

Off

Does not fill the holes in segmented objects ().

Binary Section

Parameter

Description

Binary

Selects which morphological operations are performed on the segmented (binary) image.

-

None

No operation is performed.

-

Open

Performs first erosion and then dilation. The effect is smoothing and removing of isolated pixels.

-

Close

Performs first dilation and then erosion. The effect is smoothing of the objects and filling of small holes.

-

Dilate

Enlarges the boundaries of segmented regions. Areas grow in size and holes within the regions become smaller.

-

Erode

Erodes boundaries of the segmented regions. The areas shrink in size and holes within the areas become larger.

Count

Sets how often the selected binary operation is performed with the slider or input field.

Separate Section

Parameter

Description

Separate

Selects whether you want to process the image further after segmentation. Objects that are touching one another can be separated using different methods.

-

None

Objects are not separated.

-

Morphology

Separates objects by first reducing and then enlarging them, making sure that once objects have been separated they do not merge together again.

-

Watersheds

Separates objects that are roughly the same shape. The result is two shapes separated by a thin 1-pixel boundary. The rest of the shape perimeter remains unchanged. This method may however result in the splitting of elongated objects.

Count

Sets the count value, which is similar to a Sigma for Gauss applied to a binary image.

Suppress Section

Parameter

Description

Suppress Invalid

Activated: Discards invalid pixels at the border of the image.

Suppress Border

Only visible if Variance-Based Thresholding is selected.
Activated: Suppresses the border pixels which might be incorrect, as areas outside of the image are filled with zeros. The excluded area depends on the used kernel size.

Segmentation Method Selection Dialog

With this dialog you can select the method that is used for segmenting the class currently selected in the class list.

Parameter

Description

Global Thresholding

Applies a fixed threshold across the entire image to segment objects of interest. Use it for images with consistent object intensity like fluorescence images.

AI Instance Segmentation

Uses a deep learning model trained on arivis Cloud to distinguish and separate individual objects, even if touching or overlapping. Use it for precise identification in complex images. You need the Docker Desktop software running on your PC and have a suitable model available, see Machine Learning and AI Functionalities in ZEN core.

AI Semantic Segmentation

Uses a semantic machine learning model trained with Intellesis in ZEN core or arivis Cloud for classifying regions. Use it for labeling image regions by predefined classes, using random forest or deep learning. For semantic segmentation models, you need an installation of the 3rd party Python Tools.

Background Subtraction

Uses a rolling ball algorithm to subtract uneven background, then applies a global threshold to segment objects. Use it for images with varying background intensity.

Variance-Based Thresholding

Segments based on intensity changes. Use it for brightfield images where objects are distinguished by variance rather than consistent intensity.

Dynamic Thresholding

Applies local thresholds to different regions to handle inhomogeneous backgrounds. Use it for images with uneven illumination.

Don't show this automatically

Activated: The dialog is not opened automatically anymore for all users and can only be opened with the Explore button.
Deactivated: The dialog opens automatically when entering the respective step of the image analysis.

OK

Uses the selected segmentation method for the class and closes the dialog.

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