Surface Filter

The Filter tool provides several common vision processing filters that you can apply to surface data, as well as a two "cropping" filters that output a subset of the surface data, letting you pre-process scan data to get more repeatable measurements. Any Surface or Feature tool can use the resulting filtered surface data as input.

For a list of the filters, see Filters.

The Filter tool provides no measurements or decisions, as its only purpose is to output processed surface data.

A limited set of filters is also available on the Scan page. These filters let you process scan data without needing to add tools. This can be useful if you are using a sensor mostly as an acquisition device.

For information on adding, managing, and removing tools, as well as detailed descriptions of settings common to most tools, see Tool Configuration.

Inputs

You configure the tool's inputs in the expandable Inputs section.

To use a measurement as an anchor, it must be enabled and properly configured in the tool providing the anchor. For more information on anchoring, see Measurement Anchoring.

Inputs
Name	Description
Enable Batching	When Enable Batching is checked, the tool takes an array as input and processes each surface in the array individually. There is no limit to the size of the array, other than processing limitations of the sensor. For more information on arrays, batching, and aggregating, see Arrays, Batching, and Aggregation.
Surface Input	The data the tool applies measurements to or processes.
Anchor X Anchor Y Anchor Z	The X, Y, or Z measurement of another tool that this tool uses as a positional anchor. Positional anchors are optional.
Anchor Z Angle	The Z Angle measurement of another tool to use as a rotational anchor for this tool. Rotational anchors are optional.

Parameters

You configure the tool's parameters in the expandable Parameters section.

Parameters
Parameter	Description
Show Advanced Filters	When enabled, displays advanced filters in Filter Type (see below), in addition to the standard filters (Gap Filling, Median, Averaging, and Decimation).
Regions	When expanded, displays the region- and mask-related settings.
Enable	Enables regions and displays the region- and mask-related settings (see below).
Mask Mode Number of Regions Region Type {n} Region {n}	When you enable regions (see above), the tool displays additional settings related to the region type. For details on the regions supported by this tool and their settings, see Flexible Regions. For general information on regions and the difference between standard and "flexible" regions, see Regions.
Use Intensity	If enabled, the tool uses intensity data instead of Surface data. Only usable if Acquire Intensity is enabled on the Acquire > Scan page during scanning. Only available in the advanced filters (see above); for information on the available filters, see Filters. If disabled, the tool filters using Surface data; intensity data corresponding to filtered heightmap data will also be removed. For more information on scan modes, see Scan Modes and Intensity.
Units	Specifies whether filters use data points (pts) or millimeters (mm). Not available with all filters.
Filter Type	The type of the filter. For information on the available filters, see Filters.
Preserve Data Outside Region	Enable this setting when Mask Mode is set to Include Data in Region to include data outside the region in the Filtered Surface data output. Otherwise, the Filtered Surface data output only includes the data in the region. This setting is only displayed if regions are enabled.
Threshold	The threshold that the filter uses. (Not available on all filters.)
Symmetry	One of the following: Symmetrical, Horizontal, or Vertical. (Not available on all filters.)
Kernel Size	The kernel size that the filter uses. (Not available on all filters.)
Filter in X Filter in Y	These parameters enable filtering along the X and the Y axis, respectively. Set the corresponding window sizes in X Windows Size and Y Window Size.
External ID	The external ID of the tool that appears in GoHMI Designer. For more information, see GoHMI and GoHMI Designer.

The following filters are available in the Filter tool. Filters described below as advanced are only displayed if Show Advanced Filters is enabled.

Filters
Name	Description
Gap Filling	Fills in missing data caused by occlusions using information from the nearest neighbors. Gap filling also fills gaps where no data is detected, which can be due to the surface reflectivity, for example dark or specular surface areas, or to actual gaps in the surface. The values in Filter in X and Filter in Y represent the maximum gaps the sensor will fill. Wider than gaps will not be filled. Gap filling works by filling in missing data points using either the lowest values from the nearest neighbors or linear interpolation between neighboring values (depending on the Z difference between neighboring values), in the specified window.
Median	A median filter.
Averaging	An averaging / mean / smoothing filter.
Decimation	A decimation filter.
Gaussian (advanced)	A Gaussian filter. Set the Sigma parameter as required.
Open (advanced)	Erosion followed by dilation.
Close (advanced)	Dilation followed by erosion.
Erode (advanced)	Applies an erosion filter. Lets you specify the direction of the erosion; one of the following: Horizontal Vertical Symmetrical
Dilation (advanced)	Applies a dilation filter. Lets you specify the direction of the dilation; one of the following: Horizontal Vertical Symmetrical
Morph Gradient (advanced)	Applies a morphological gradient. The difference between dilation and erosion.
Sobel Magnitude (advanced)	Applies a Sobel magnitude filter. Lets you specify the direction of the filter; one of the following: Horizontal Vertical Symmetrical
Laplacian (advanced)	Applies a Laplacian filter. Useful for detecting areas of distinct edges. Uses the following kernel:
Negative (advanced)	Inverts the height or intensity values in the scan data. When Use Nulls is enabled, null values in the input are replaced by the highest height value.
Equalize (advanced)	Normalizes the norm or value range of an array.
Binarize (advanced)	Sets height values to a fixed value for each point that is present in the data. Can be used with a region Z offset to threshold points above/below a Z value. When Use Intensity is enabled, the tool sets data points with an intensity value over
Percentile (advanced)	Limits the scan data to points between the values you set in High Percentile and Low Percentile, which are displayed when you choose this option.
Relative Threshold (advanced)	Crops scan data based on user-specified minimum and a maximum heights. Use Reference Region to set the heights relative to a reference region.
Crop only (advanced)	Crops the scan data to the user-defined region.
Mask With Input	Uses the surface input into the tool as a mask on the data. Any points in the filtered data will be set to null if the input surface is null at the same location. For example, the Gaussian filter can extend data along the edges, adding data in areas that contain null values. This filter would remove data that the Gaussian filter introduces, preserving the null values. This filter should follow any filter that introduces this kind of unwanted data.

Outputs

All tools provide measurements, geometric features, or data as outputs.

Data
Type	Description
Filtered Surface	The filtered data, available for use as input in the Stream drop-down in other tools.