Check for Presence
Checking for the presence or absence of an object or feature is a core component of assembly verification and other types of tests. This palette groups several visual inspection steps whose purpose is determining the presence or absence of a feature. These steps use different features and properties of the image, such as intensities, edges, colors, and patterns. Use the step whose description best represents the feature that you want to detect in your image.
| Step Name | Description | ||
|---|---|---|---|
| Detect Objects | Detects the presence of objects based on their size and range of intensities. In addition to detecting the presence of an object, this step counts the number of objects it finds. Refer to Detect Objects Concepts for related information. | ||
| Measure Intensity | Returns the average intensity value of pixels inside a region of interest. Use this step to detect the presence of a part with unique, uniform pixel intensities.
Another use of the Measure Intensity step is to detect objects or assemblies characterized by intensity levels that vary greatly from surrounding pixels. In such cases, the minimum and maximum intensity values and the standard deviation values can describe the contents of a region of interest. You can use these values to detect the presence or absence of a part without specifying the shape or pattern of the part. Refer to Measure Intensity Concepts for related information.
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| Count Pixels | Calculates the percentage of pixels in a region whose pixel intensities fall within a specified intensity range. Use this step to check for the presence of a part with known pixel values. | ||
| Match Colors | Detects the presence of an object by measuring the similarity between the color information of a region of interest and a template color. Use this step in applications such as color identification, color inspection, and other applications that require the comparison of color information to make decisions. Refer to Match Colors Concepts for related information. | ||
| Find Edges | Verifies the presence of objects based on the number of edges the step finds. Refer to Find Edges Concepts for related information. | ||
| Detect Defects | Compares an image to a template and returns the differences. Use the differences between the two images to identify defects in the inspection image. Refer to Detect Defects Concepts for related information. | ||
| Match Pattern | Locates regions of an image that match a predefined template of a pattern. Use this step when the feature you want to locate can only be described by its 2D intensity and edge info. For example, you can use Match Pattern to locate a company logo printed on a container. The Match Pattern step is indifferent to image noise, blur, and uniform lighting changes. Refer to Match Pattern Concepts for related information. | ||
| Geometric Matching | Locates regions in an image that match a model, or template, of a reference pattern. Geometric matching is specialized to locate templates that are characterized by distinct geometric or shape information. Geometric Matching finds templates regardless of lighting variation, blur, noise, occlusion, and geometric transformations such as shifting, rotation, or scaling of the template. Refer to Geometric Matching Concepts for related information. | ||
| Match Color Pattern | Detects the presence of an object using a color template pattern that describes the edge information and color information of the object. Use this step if the object contains color information that is very different from the background, and you want to find the precise location of the object in the image or count the number of objects present in a region of the image. Also, use this step if the object has grayscale properties that are very difficult to characterize or that are very similar to other objects in the image. Refer to Match Color Pattern Concepts for related information. |
