What is a 3D vision system & is it right for you?

November, 2019

3D machine vision has steadily gained popularity in manufacturing as it provides a robust solution for inspection and measurement. Where 2D vision can fall short due to misalignment, glare, or lack of contrast, 3D vision technology can really shine.

While there are several technologies out there for creating 3D images, the two most commonly used for inline inspection are pattern projection and laser profilers. Below is a brief overview of each, along with a few key differences and links to more information on KEYENCE's 3D vision systems.

3D Machine Vision Technology

1 What is pattern projection?

Pattern projection strobes and captures a series of striped patterns. Topographical information is extrapolated based on how the patterns are distorted. Multiple patterns are projected and captured to minimize missing data points. Because several images are taken, the part must be fully stopped during the capture process. It is possible to use multiple projectors or cameras to reduce blind spots.

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2 What is a laser profiler?

Laser profilers are 2D displacement sensors that emit a laser line and capture height data to create an accurate profile of the target shape. A 3D image is generated by stitching together a collection of profiles taken at equal spacing over a part. Because the 3D image is created by compiling several 2D profiles, either the part or the laser profiler must be moved to create the image. This method is ideal for continuous processes.

3 Which 3D technology is right for your application?

Although both technologies are capable of generating high quality 3D images, there are a few reasons one approach may be better suited for an application than the other. Below are a couple questions to help identify which solution may be a better fit for you. If you have any questions or an application you'd like to review, you can request a free consultation with one of our local 3D vision specialists.

Can the part be fully stopped during inspection?

Yes: Pattern Projection

No: Laser Profiler

Why? Pattern Projection requires the part to remain stopped while several patterns are projected and captured. If the part can't be stopped briefly, Pattern Projection will not work for your inspection. Conversely, laser profilers require relative motion between the sensor and part to create a 3D image.

Are any critical features or tolerances < 0.1 MM?

Yes: Laser Profiler

No: Pattern Projection

Why? Laser profilers typically provide more accurate 3D data because they combine several high accuracy height profiles to generate a 3D image Whereas Pattern Projection extrapolates 3D information based on distortions in a projected pattern.

4 APPLICATIONS OF 3D VISION

3D vision provides additional stability to inline inspection and measurement because it allows users to collect more information about the target prior to passing judgment. For example, is the part tilted? Compensate for misalignment prior to making measurements. Do you need to measure depth as well as X/Y location? Perform that inspection with a single inspection tool.

Here are a few other examples of how 3D vision is applied in manufacturing.