The spatial distance represents the horizontal distance between image objects on the same level in the image object hierarchy.
Feature distance is used to analyze neighborhood relations between image objects on the same image object level in the image object hierarchy. It represents the spatial distance in the selected feature unit between the center of masses of image objects. The (default) value of 0 represents an exception as it is not related to the distance between the center of masses of image objects; only the neighbors that have a mutual border are counted.
Figure 137: The image object hierarchy describes multiple image object levels.
The Spatial Distance ^ describes the horizontal distance between image objects.
The Level Distance _ describes the vertical distance between object levels.
7.5.1.4 Thematic Attributes
Thematic attributes can only be used if a thematic layer has been imported into the project. If this is the case, all thematic attributes in numeric form that are contained in the attribute table of the thematic layer can be used as features in the same manner as you would use any other feature.
The Thematic Layer Attribute Table can be accessed from the main menu by choosing one of the following:
• Tools >Thematic Layer Attribute Table
• View > Windows >Thematic Layer Attribute Table
Thematic Layer Attribute Table
To view the thematic attributes, go to the Manual Editing toolbar and select Thematic editing under Change Editing Mode. From the Select thematic layer drop-down list, choose the name of the thematic layer whose attributes you want to display. The attributes are shown in the Thematic Layer Attribute Table.
7.5.1.5 Legacy Features
A legacy feature is a feature introduced in earlier versions of Definiens software. Legacy features are listed in the feature tree, to enable usage of projects or rule sets that have been created by earlier versions of Definiens. The latest possible version number for usage of a legacy feature is noted after the feature name in the feature tree, for example, Elliptic fit (legacy feature, up to V3.5). If available, legacy features enable you to work consistently with rule sets created using earlier versions of Definiens software. However, we recommend adapting these rule sets on the current feature version to enable the most accurate results.
7.5.1.6 Object Oriented Texture Analysis
Object-oriented texture analysis allows you to describe image objects by their texture.
Precondition: An image level of subobjects has to exist.
By looking at the structure of a given image object’s subobjects, an object’s form and texture can be determined. An important aspect of this method is that the respective segmentation parameters of the subobject level can easily be adapted to come up with subobjects that represent the key structures of a texture.
A straightforward method is to use the predefined texture features provided by Definiens Developer. They enable you to characterize image objects by texture, determined by the spectral properties, contrasts and shape properties of their subobjects.
Another approach to object oriented texture analysis is to analyze the composition of classified subobjects. Class-related features (relations to subobjects) can be utilized to provide texture information about an image object, for example, the relative area covered by subobjects of a certain classification.
Further texture features are provided by texture after Haralick. These features are calculated based upon the so-called co-occurrence matrix, which is created out of the pixels of an object.
Note
The calculation of Haralick texture features can require considerable processor power, since for every pixel of an object a 256 x 256 matrix has to be calculated.
Manual Editing View Thematic Layer Attributes on page 287 Work with Thematic Layers on page 284
7.5.2 About Metadata as a Source of Information
Many image data formats include metadata providing information about the related image, for example the acquisition time. Considering metadata might be beneficial for image analysis if you relate it to features.
The available metadata depends on the image reader or camera used, the industry-specific environment, and settings. Industry-industry-specific examples are:
• Satellite image data may contain metadata providing cloudiness information.
• Microscopy image data may contain metadata providing information about the used magnification.
Definiens Developer can provide a selection of the available metadata. This selection is defined in a metadata definition which is part of the rule set.
The provided metadata can be displayed in the Image Object Information window.
Further, it is listed together with features and variables in the feature tree of for example the Feature View window or the Select Displayed Features dialog box.
Convert Metadata to Provide it to the Feature Tree
When importing data, you can provide a selection of available metadata. To do so, you have to convert external metadata to an internal metadata definition. This provides a selection of the available metadata to the feature tree and allows its usage in rule set development.
When developing rule sets, metadata definitions will be included in rule sets allowing the serialization of metadata usage.
Metadata conversion is available within the following import functions:
• Within the Create Project dialog box.
• Within the Customized Import dialog box on the Metadata tab.
7.5.3 Investigate Single Image Objects by Using the Image Object Information
When analyzing individual images or developing rule sets you need to investigate single image objects often. Use the Features tab of Image Object Information window for acquiring information on a selected image object. It makes the classification process transparent and amendable while allowing you to obtain specific information about an image object.
Image Objects consist of spectral, shape, and hierarchical elements. These elements or characteristic attributes are called Features in Definiens Developer. In the Feature tab within the Image Object Information window, the values of the characteristic
attributes of the selected features are displayed when an image object is selected from within the project view.
The Image Object Information 2 window offers the same functionalities as the Image Object Information window. It can be used for comparison of image objects.
Investigate Single Image Objects by Using the Image Object Information on page 174 Select Features on page 461
Create a New Project on page 44
Metadata Import Options on page 72
Select and Deselect Image Objects on page 115
Prerequisite: Before a feature of image object can be displayed in the project view an image must be loaded and a (any) segmentation must be applied to the project.
1. To open the Image Object Information window do one of the following:
• Choose View > Image Object Information on the main menu bar.
• Choose Image Objects > Image Object Information on the main menu bar.
2. To acquire information on a specific image object click an image object in the project view. Some features are listed by default.
3. To add or remove features, right-click the Image Object Information window and choose Select features to Display. The Select Displayed Features dialog box opens Select the feature of your interest.
Figure 138: Image Object Information window.
4. The selected feature a values are now displayed in the project view. To compare single image objects, click another image object in the project view and the displayed feature values are updated.
Figure 139: Project view of selected image object values. (Image data courtesy of EMBL Heidelberg).
Selected image object with the calculated means of the image layers displayed under the cursor.
5. Double-click a feature a to display it in the project view.
6. To deselect a selected image object, click it in the project view a second time.
7. If the processing for image object information takes too long, or if you want to cancel the processing for any reason, you can use the Cancel button in the status bar to cancel processing.
Create Image Objects by Segmentation on page 157 Image Object
Information
Select Features on page 461
Get a Visual Overview of Feature Values on page 180
Cancel Image Analysis of an Open Project on page 372
Options
The advanced functionalities of the Classification tab and Class Evaluation tab are mentioned in the About Classification section.
Context Menu Options
a= To display available context menu commands, right-click a feature a in the Image Object Information window.
Note
Only the available context menu options applicable to the selected feature will be displayed. They differ according to the selected feature and by different products.
Image Object Information Context menu commands
Usage