# Measurements

Use the Measurements tab to specify how measurements are made during blob analysis.

At the top of this tab is a table of measures that you can add. For a description of the possible measures, see the BlobMeasureConstants API. This collection of measure modes and this equivalent to the BlobMeasureCollection.

For each measure mode you select, you have a set of properties to specify:

- Mode indicates how measure will be used during blob analysis.
- FilterMode is available only if you select Filter. Specifies how the filter range is interpreted -- whether blobs are within range specified or outside of it.
- Low is available only if you select Filter. Specifies low end of filter range.
- High is available only if you select Filter. Specifies high end of filter range.

The sorting parameters allow you to sort the filtered collection of blobs as desired: .

- Enabled enables the sorting of the filtered collection of blobs.
- Ascending sorts the blobs in ascending order.
- Measure is the blob measure that will be used for sorting the filtered collection of blobs.

Extrema parameters define how the tool determines what pixels at the extreme portions of a blob are not actually part of the blob.

- Exclude Mode defines the mode used to exclude part of a features area when computing a bounding box or median point of a blob.
- Area is the amount of area to exclude when computing a bounding box or median point. Depending on the exclude mode selected, this parameter can also be equivalent to the ExtremaExcludeAreaPercent or ExtremaExcludeAreaPixels.
- Angle is the angle that you want the bounding box or median point of a blob to be based on. Although you can specify this value in either degrees or radians, the underlying tool stores this value in radians.

The Compute parameters define which blob properties are computed and displayed as computation results. To improve the speed of the tool, you can disable the computation of specific blob results that you do not need. By default, all results are computed. To disable the computation of a specific blob result, uncheck the corresponding checkbox.

- BlobRLE enables saving run lengths of regions in the blob scene description. You must set this to true if additional blob measurements are required, such as region boundary, perimeter, or region image.
- Inertia enables the computation of the inertia, principal inertia, angle, and elongation of the regions.
- Topology enables the computation of parent-child relationships between regions.