Reflection Filter

The Reflection filter removes points that Zivid deem as impacted by reflection and thus erroneous. These are typically seen in the point cloud as “ghost planes” - small regions of points floating mid-air that shouldn’t be there.

Zivid knows how the signals it sends out from the projector should look like. For this reason it is possible to assess whether or not the data that is read back by the camera makes sense. The reflection filter, therefore, attempts to discard pixels that are deemed to be tampered with as a result of one of the following:

Interreflections
Excessive movements in the scene
Alternating alien light sources
- For example a second Zivid 3D camera that projects onto the same scene at the same time.

The following values should be used:

Value	Condition
`Enabled::no`	If you know that your scene is not reflective, and you want to optimize acquisition time.
`Enabled::yes`	Turn on if you have issues detecting parts that are reflective or are inside a reflective bin.

The Reflection filter has two modes: Global (default) and Local. These modes have different benefits and downsides, depending on the used Vision engine.

Omni

Mode	Pros
`Mode::global`	Higher dynamic range with lower exposure
`Mode::local`	Correct 3D data on thin and pointy objects (see How to preserve Thin and Pointy Objects in the Point Cloud for more details) Correct 3D data in projector shadows and low signal regions

The images below highlight the main advantage of Global mode, its higher dynamic range, as can be seen on the coverage on shiny black objects in this scene.

Although Local mode has a reduced dynamic range, this can be compensated for by increasing the exposure time, as demonstrated in the comparison images.

Reflection Filter - Local mode (increased exposure)

The images below illustrate the benefits of Local mode.

Phase / Stripe

Mode	Pros
`Mode::global`	Preserving the sides and edges of objects Removing outlier points in the point cloud
`Mode::local`	Correct 3D data on thin and pointy objects (see How to preserve Thin and Pointy Objects in the Point Cloud for more details) Processing time (up to three times faster, see processing time for global below)

The images below highlight the main advantages of Global mode: better data on object sides and edges, and fewer outliers.

The floating points (outliers) that Local mode cannot remove are typically removed by the Cluster Filter.

The images below illustrate the benefits of Local mode: preserving data on thin and pointy objects.

Reflection filter (Global mode) adds the following processing time per 3D capture:

Omni

No additional processing time is added when using the Omni engine.

Phase / Stripe

hidden

	2+R		2+		2
	High-end NVIDIA	High-end Intel	High-end NVIDIA	High-end Intel	High-end NVIDIA	High-end Intel
Filters
ReflectionGlobal	6 ms (±1)	10 ms (±1)	5 ms (±1)	11 ms (±2)	14 ms (±8)	30 ms (±5)
ReflectionLocal	0 ms (±0)	0 ms (±0)	0 ms (±0)	0 ms (±0)	0 ms (±0)	0 ms (±0)

Version History

SDK	Changes
2.16.0	Reflection filter mode Local can now be used with the Omni engine.
2.12.0	Stripe Engine removed from experimental. Reflection filter mode Local is now up to 15% faster.
2.11.0	Reflection filter mode Local can now be used with the Stripe engine.
2.7.0	Reflection filter is updated with a new mode called Local. Old mode is renamed to Global.
1.4.0	Reflection filter is improved to remove fewer good points.