What are the advantages of image-based 3D measurements? 

In this article:

• Image‑based 3D measurements in Remote Visual Inspection equipment enable inspectors to map, measure, and analyze defects in 3D, improving accuracy and reducing subjectivity versus traditional 2D methods.
• Real3D point‑cloud data lets users verify data quality and cursor placement, delivering more precise, repeatable measurements that support safer, better maintenance decisions.
• Advanced video borescopes and software allow re‑measurement and analysis after inspection, helping minimize downtime, avoid unnecessary repairs, and protect asset integrity.

What are the advantages of image-based 3D measurements?

Advances in image based 3D measurement are making the video borescope an increasingly powerful tool in the inspector’s toolbox. While in the past, you could identify indications and capture images; today’s advanced video borescopes allow you to map, measure, and analyze indications in 3D.

This guide is designed to help inspectors and asset owners understand measurement technologies available on the Mentor Visual iQ and how they can be properly applied to improve decision making in remote visual inspection applications.  

Many video borescope owners underutilize the advanced features of their inspection equipment due to a lack of training. Using this handbook as a guide, you can learn to apply new techniques, and make your expertise a competitive advantage for your organization  Advanced training is available through the Waygate Inspection Academy.

The Importance of Measurement Precision & Accuracy

Remote Visual Inspection (RVI) is frequently used to determine the serviceability of an asset. That determination is often based on the measurement of an indication or feature inside the asset  Inaccurate measurements can result in unnecessary downtime, scrap, and maintenance costs, as well as safety or reliability risks. It is therefore critical that you understand how to properly apply available measurement capabilities to maximize the quality of decision making.

With traditional measurement technologies, such as stereo, shadow, or comparison, you have little ability to assess either the quality of the data used to compute the measurement result or the correctness of the cursor placement for the desired measurement. This can often lead to inaccurate and inconsistent measurements and potentially costly incorrect decisions.

The latest Real3D measurement technologies provide an interactive, fully-surfaced 3D point cloud that can be used to assess the 3D data quality and verify proper cursor placement on the 3D surface.

Accurate VideoProbe™ measurement requires:

Measurement accuracy and minimum feature size depend on many factors that vary from application to application. Under good conditions, Real3D measurement technologies are often capable of resolving feature depths down to ~0.125mm (0.005”) and achieving measurement errors in the +/- 0.05mm (+/- 0.002”) range or better.

Performing a Gauge R&R study using representative known samples is recommended to determine if the accuracy/precision requirements of a particular application can be met. Please reach out to your local sales representative for more information to see what Real3D measurement can do for you.

Ideal conditions vary by measurement technology as described below:

Real3D Phase Measurement ideal conditions

• Measurements by a qualified RVI technician
• Clean and calibrated optical tip adapters and camera lens
• Camera positioned very close to the indication, even if slightly out of focus
• Camera positioned in a non-perpendicular incident angle to the surface
• Measurement upon a matte surface finish
• Minimal projected-pattern reflection from nearby shiny surfaces onto the measurement area
• Absence of ambient light
• Systems may be unable to both view and illuminate the bottom of narrow, deep features with either structured light patterns or normal illumination, making them unable to determine accurate 3D data at the bottom of such features.

Real3D Stereo and Stereo Measurement ideal conditions

• Measurements by a qualified RVI technician
• Clean and calibrated tips and camera lens
• Camera positioned very close to the indication and in sharp focus
• Measurement on surfaces that contain differentiated surface textures
• No glare on the indication

Inspection Manager

Inspection Manager is a Windows PC-based software tool which allows the re-measurement and analysis of any measurement image captured by a Waygate Technologies VideoProbe. The tool allows you to move measurement cursors, add measurements, or completely clear out previous measurements and begin a new measurement process. If the measurement image was captured with a 3D-Stereo or 3D-Phase process, this tool also allows full point cloud viewing and manipulation.