Blob

Count

Returns the total number of blobs identified, based on the tool's parameters.

Area {n}

The area of a blob.

The area is calculated using the contour of the blob and resampling. For this reason, areas calculated using the Surface Volume tool will produce different measurements; for more information, see Area.

X Center {n}

Y Center {n}

The X and Y positions of the center of mass of a blob extracted from the surface.

The Number of Blob Outputs setting determines the number of measurements listed in the Measurements tab.

Z Average {n}

Z Min {n}

Z Max {n}

The average, minimum, and maximum Z value of a blob extracted from the surface.

The Number of Part Outputs setting determines the number of measurements listed in the Measurements tab.

An array containing the blobs. For an example of how to access this data from an SDK application or a GDK tool, see the appropriate sample in the SDK samples; for more information, see Setup and Locations.

Surface data you can use to evaluate the impact of the tool's parameters, before the tool's filters are applied, to properly separate the areas corresponding to the defects or targets you need to detect.

The sensor, or combination of sensors, that provides data for the tool's measurements. For more information, see Source.

If enabled, the tool uses intensity data instead of heightmap data. Only available if Acquire Intensity is enabled on the Scan page during the scan; for more information, see Scan Modes.

Limits blob detection to a user-defined region.

If this option is not checked, the tool detects blobs in the entire active area.

In the following, blobs are only detected in the rectangular measure region:

When you enable Use Measure Region, the tool displays this and additional settings related to the type selected in this parameter. For details on flexible regions and their settings, see Flexible Regions.

For general information on regions and the difference between standard and "flexible" regions, see Regions.

Provides three options: None, Reference Region, and Reference Plane. If the reference type is set to None, the Height Threshold setting is absolute (relative to zero). For the Reference Region and Reference Plane options, see the descriptions of the Reference Region Type and Reference Plane parameters below.

If you set Reference Type (see above) to Reference Region, the tool displays a drop-down that lets you choose the reference region type, as well as additional settings related to the type you select. (For details, see Flexible Regions.) The tool calculates an average height or intensity of the data in the reference region. Height Threshold is relative to this value.

For example, in the following, blobs are detected using a relative height threshold of -0.2 mm, relative to the average in the reference region:

For general information on regions and the difference between standard and "flexible" regions, see Regions.

If you set Reference Type (see above) to Reference Plane, the tool uses the specified plane geometric feature to correct for a tilt of the target. Note however that using a reference plane to correct the tilt distorts the scan data: it sheers the data by the same angle as the tilt. The maximum tilt angle with which you can use the tool therefore depends on how much sheer angle you can tolerate in your application (which can effect the tool's ability to detect blobs). Typically, you add and configure a Surface Plane tool to generate a plane (for more information, see Plane). For information on geometric features, see Geometric Features.

For applications where sheer distortion can't be tolerated, use Surface Transform to correct the tilt (see Transform), and use the latter tool's output as the input for Surface Blob.

For example, in the following, despite the overall tilt of the target, the tool detects the flaws on the surface. (Note the gradient of the heightmap colors, indicating a height difference of roughly 9 millimeters between the lower and higher areas near the dents on the target's surface.)

Indicates whether null points (points where no height or intensity value is available, due to dropouts or regions outside of the measurement range) are filled with the value in Null Fill Value as a general “background level” or to fill gaps to aid in isolating blobs.

If Use Intensity is enabled, the value in Null Fill Value is an intensity.

The threshold above or below which data is considered for being a blob. Use the Threshold Direction setting to determine whether data above or below the threshold is considered.

If Use Intensity is enabled, this setting is named Intensity Threshold. Otherwise, it is named Height Threshold.

Determines whether data above or below the threshold is considered as being a blob.

Below: The Height Threshold value is the maximum that will be considered as part of a blob (for example, a dent below the surrounding surface).

Above: The Height Threshold value is the minimum that will be considered as part of a blob (so a raised feature).

The X and Y kernel size, respectively, for morphological opening to remove small areas of data. Use these settings, for example, to remove bridges between areas to properly isolate them or to remove small areas entirely (perhaps caused by noise). Use different values of X and Y to use a non-rectangular filter to adapt the kernel to the kinds of unwanted data you see in the scan data.

The X and Y kernel size, respectively, for morphological closing to fill in holes smaller than the specified kernel size. Use these settings, for example, to fill small areas within potential blobs that may be caused by drop-outs. Use different values of X and Y to use a non-rectangular filter to adapt the kernel to the kinds of holes you see in the scan data.

Provides options to let you find either external blobs only or both external and internal blobs.

External Blobs

Use this option to ignore smaller blobs in larger blobs: only the outermost blob is returned.

External + Internal Blobs

Use this option to include smaller blobs in larger blobs.

If Use Area Filter is enabled, the tool applies an area filter to potential blobs using the values in Max Area and Min Area.

If Use Aspect Filter is enabled, the tool applies an aspect filter (ratio of length and width) to the rotated bounding box that would encapsulate the area, using the values in Max Aspect and Min Aspect.

For example, the following dent in a surface is included as a blob if these aspect values are set to 1 and 0.354, respectively (the rotated bounding box encapsulating would be 13.059 mm x 4.704 mm).

In the following, the same dent is excluded if Min Aspect is set to a value greater than 0.354.

If Use Circularity Filter is enabled, the tool applies a circularity filter to potential blobs to measure how close to a circle the blob is, using the values in Max Circularity and Min Circularity . Circularity is determined from area within the contour of the blob and the perimeter of its contour. With increasing perimeter for the same area, circularity is reduced.

If Use Convexity Filter is enabled, the tool applies a convexity filter to potential blobs, using the values in Max Convexity and Min Convexity . Convexity is defined as the (Area of the Blob / Area of its convex hull), and "convex hull" of a shape is the tightest convex shape that completely encloses the shape.

Orders the measurements, features, and surface data of the individual blobs output by the tool. Choose one of the following:

• Area - Large to small
• Area - Small to large
• Position - X increasing
• Position - X decreasing
• Position - Y increasing
• Position - Y decreasing

Determines the number of blobs the tool outputs as measurements, features (center points of blobs), and surface data. Currently limited to 200 blobs.

When this parameter is enabled, the tool outputs the minimum, maximum, and average Z value of each blob. This can be useful in applications where a large number of blobs is expected when you need these Z measurements for each one.

The filters that are applied to measurement values before they are output. For more information, see Filters.

Lets you choose the X, Y, or Z measurement of another tool to use as a positional anchor for this tool.