Real3D™
Measurement
Handbook
A guide to advanced
3D measurement
technologies, techniques
and applications forvideo borescopes
used in remote visualinspection applications.

Get the most from your
Mentor Visual iQ+.

TABLE OF CONTENTS

Introduction��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������3
The Importance of Measurement Precision & Accuracy �����������������������������������������������������������������������������������������������������������������������������������������������3
Enabling Technologies and Connectivity����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������3
Measurement Technologies
3D Phase Measurement���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������4
3D Stereo Measurement��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������4
Stereo Measurement����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������4
Comparison���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������4
PC Re-Measurement�����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������4

3D Measurement Best Practices: Techniques and Tips ���������������������������������������������������������������������������������������������������������������������������������������������������5
Choosing the Right Measurement for Your Application���������������������������������������������������������������������������������������������������������������������������������������������������8
Measurement Types

Length�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������9

Point to Line��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 10

Depth��������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 11

Area���������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 12
Multi-Segment������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 12
Depth Profile������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 13
Area Depth Profile.....................................................................................................................................................................................................................................................................................................14
Blade Tip Clearance..............................................................................................................................................................................................................................................................................................15
Blade Tip Clearance Advisory Messages.........................................................................................................................................................................................................................................16
Surface Angle...............................................................................................................................................................................................................................................................................................................17
Angle......................................................................................................................................................................................................................................................................................................................................18
Missing Corner.............................................................................................................................................................................................................................................................................................................18
Radius Gauge...............................................................................................................................................................................................................................................................................................................19
Measurement Plane...............................................................................................................................................................................................................................................................................................20
Measurement Plane Guidelines.................................................................................................................................................................................................................................................................21
Measurement Plane Examples....................................................................................................................................................................................................................................................................22
3D Stitching (3DS).....................................................................................................................................................................................................................................................................................................24

Measurement Accuracy Data����������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������� 27
Real3DTM Measurement Part Numbers and Specifications�����������������������������������������������������������������������������������������������������������������������������������������29
Glossary of Terms�������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������������30

2

Introduction

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 tomap, 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 yourorganization. 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 toproperly 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 assessthe 3D data quality and verify proper cursor placement on the 3D surface.

Accurate VideoProbe TM 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

Real3D Stereo and Stereo Measurement ideal conditions• Clean and calibrated optical tip adapters and camera lens

• Clean and calibrated tips and camera lens

• Measurements by a qualified RVI technician• 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• Measurements by a qualified RVI technician• Camera positioned very close to the indication and in sharp focus• Measurement on surfaces that contain differentiated surface textures• No glare on the indication• 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 ofnarrow, deep features with either structured light patterns or normal
illumination, making them unable to determine accurate 3D data at thebottom of such features.

Real3D Measurement Handbook | 3

Measurement Technologies(See Mentor Visual iQ VideoProbeTM Operating Manual – Advantages of Measurement Types)

3D Phase Measurement

Using patented structured-light technology, 3D Phase Measurement enables inspectors to locate, measure, and analyze an indication
using the same tip optic. The wide field of view and large depth of field allow for measuring with the same tips used for inspecting, thus
eliminating the extra steps required to back out, change the tip, and then relocate the indication.
3D Phase Measurement provides accurate measurement “on-demand” while saving time and increasing overall inspection productivity.
3D Phase Measurement employs structured light patterns projected from the tip to create a 3D surface scan of the viewing area andcan measure all aspects of surface indications.

Benefits:• View and manipulate a 3D point cloud for detailed assessment of surface shape and measurement correctness• Full-screen viewing of measurement image for greater resolution• Navigate, inspect and measure without changing probes or tip optics• Available on 6.1 mm diameter probes• Green side view tip provides ability to measure larger areas and at distances up to 4.7 inches• Measurements can be refined by moving cursors within the point cloud

3D Stereo Measurement

3D Stereo Measurement utilizes the same optical tips as traditional Stereo Measurement, but employs more advanced calibration andprocessing algorithms to generate a full 3D point cloud representation of the target surface that can be viewed, manipulated, and analyzed.

Benefits:• More accurate, precise measurement compared to traditional or manually matched stereo measurement• Provides better matching capabilities than Stereo Measurement on horizontal and repeating indications• View the camera image and 3D point cloud side-by-side for highly efficient measurement analysis• Measure effectively on shiny (or highly-reflective) surfaces which include detail, especially when using Image
Brightness and Dark Boost• Measure on surfaces with some minor movement present• Available on 4.0, 6.1, 6.2 working channel and 8.4 mm probe diameters

Stereo Measurement

Traditional stereo measurement, which, like 3D Stereo, utilizes a prism to obtain left and right stereo images from slightly different
perspectives. The matching of surface points in the left and right images at the cursor locations allows 3D coordinates andmeasurement results to be computed. This technology, available for more than two decades, is useful on systems with limited
computing power, but does not provide a 3D point cloud and therefore limits the inspector’s ability to assess measurement quality.

Comparison Measurement

A more traditional 2D measurement technology that uses a physical reference target placed by the manufacturer or inspector at thesame tip to target distance as 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, orcompletely 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.

4How to choose the right tip for the job
3DPM Measurement Tips Selection Guide

Two main things to consider when selecting a 3DPM tip are from what direction the defect is viewed and from how far away. To
determine whether you need a forward view or side view tip, consider where your insertion point is in relation to the area you're
inspecting. Measurement Depth of Field (DOF) values are provided as general guidelines to help select the most appropriate
tip for a given application. The actual measurement DOF for a particular application depends on several factors including
feature size, required accuracy, measurement types and surface finish.

Forward View Tip Specs

1

3

2

4

5

6

7

8

9

10

11

Inches
OpticalMeasurement

Part Number

Black, Orange, and Yellow forward view tips comparison chart.
Color

FOV
(deg)

Optical DOF(mm / in)

Measurement DOF(mm / in)

Measurement view
size at max distance

Black

105

8mm-250mm
0.31”-9.84”

8mm-50mm
0.31”-2”82mm x 55mm
3.2" x 2.2"

Yellow

105

15mm-inf
0.59”-inf

15mm-60mm
0.59”-2.36”

99mm x 66mm
3.9" x 2.6"

Orange1053mm-120mm
0.12”-4.72”

3mm-35mm
0.12”-1.38”

58mm x 38mm
2.3" x 1.5"

XL4TM61105FG

XL4TM61105FF

XL4TM61105FN

Real3D Measurement Handbook | 5

Side View Tip Specs

1

3

2

4

5

6

7

8

9

10

11

Inches

OpticalMeasurement

Blue, Green and Red side view tips comparison chart.
Note: Green tip view is tilted up 10 degrees to improve turbine blade root visibility
Part Number

Color

FOV
(deg)

Optical DOF(mm / in)

Measurement DOF(mm / in)

Measurement view size
at max distance

Blue

105

7mm-250mm
0.27”-9.84”

7mm-50mm
0.27”-2”82mm x 55mm
3.2" x 2.2"

Green

105

15mm-inf
0.59”-inf

15mm-120mm
0.59”-4.7”200mm x 130mm
7.8" x 5.2"

Red

105

2mm-20mm
0.078”-0.78”2mm-20mm
0.078”-0.78”33mm x 22mm
1.3" x 0.9"

XL4TM61105SG

XL4TM61105SF

XL4TM61105SN

6

General Guidelines• Ensure the inspector is qualified to perform measurement.
• U se in-house procedures and the selector tool on this page to choose the appropriate measurement technology and type for your application.
• E nsure that your measurement tip and probe optics are clean and that the tip is securely attached. If using a stereo tip, be sure to correctly
identify the tip serial number when first entering measurement. 3D Phase Measurement tips are automatically recognized by the system.
• F or best results when measuring on a narrow surface using 3DPM, orient the tip such that the long dimension of the surface is perpendicular tothe projected pattern lines. With forward view black, orange, and yellow and side view green tips, the projected lines are horizontal in the image,so narrow surfaces are best oriented vertically. With side view blue and red tips, the projected lines are vertical in the image, so narrow surfaces
are best oriented horizontally.
• W ith Stereo and Real3D Stereo Measurement, lines or part edges should be oriented vertically rather than horizontally to help thesystem more precisely identify matching point positions in the horizontal direction.
• V erify that the system measures accurately with the Waygate Technologies NIST traceable verification block before and after
performing measurements.
• P osition the tip as close as possible to the measurement area (a high Index or low MTD value). Stereo and 3D Stereo require the image
to be in focus, but with 3D Phase Measurement, small depth measurements (< 0.010”) are generally most accurate when close enoughfor the image to be somewhat out of focus. Measuring from too far away is the most common cause of inaccurate measurements.
• P ay attention to advisory messages displayed by the system during measurement, which may signal improper setup or inappropriate
MTD for the measurement performed.
• C heck and adjust the measurement setup and cursor placement with the 3D point cloud view. Many issues are difficult to recognize
using the 2D white light image alone but are obvious in the 3D point cloud.
• W hen performing small depth or depth profile measurements, use the 3D point cloud view with depth map enabled to verify that theindication clearly stands out from the data noise. If not, capture another image from a closer distance or different orientation.
• W hen measuring the depth of a feature such as a pit or dent, use the point cloud view to verify that you are measuring at its deepest
point and that the measurement reference plane is accurately aligned with the reference surface.
• W ith 3D Phase Measurement, reflections or shadowing can create regions of lower-quality data, which are highlighted in yellow. Avoid
measuring in these areas whenever possible, especially for depth, depth profile, or area depth profile measurements.. Performing
another capture from a different orientation may eliminate the yellow regions.
• W hen using 3D Phase Measurement, off-perpendicular views yield the best results for depth measurements, especially whenmeasuring objects with shiny surfaces.
• A reas where the system was unable to determine 3D coordinates are highlighted in red. Measurements cannot be taken in these redareas. Measurement data around these unmeasurable areas should be closely evaluated for data validity.
• F or best data quality, keep the probe as still as possible during image capture. This is particularly important with 3D Phase
Measurement due to the large number of images captured.
• W ith 3D Stereo, adjust image brightness, dark boost levels and viewing orientation to minimize glare in the area of interest prior tocapturing a measurement image.
• S traight lines or edges on viewed objects often appear curved in the 2D image due to the viewing perspective and optical distortion.
As all measurements are performed in 3D, the straight 3D measurement lines are drawn on the 2D image as they would be seen by
the camera, which is often curved. This helps with alignment to straight edges and more accurately indicates measurement location.
• Use 3X Zoom window for more precise cursor placement.
• Utilize 3D surface mask to optimize cursor placement• Apply Inverse+, HDR Variable and Dark Boost image transforms to aid in indication analysis

Real3D Measurement Handbook | 7

Choose the Right Measurement
Type For Your Application
While multiple measurement types may be used for certain applications,this chart is intended to show the expert recommendation.

Length• Simple measurement of features orcomponents

Point to Line• Turbine blade edge damage• Gap width• Weld width

Depth• Pits or dents from corrosion, erosion, or FOD
impact• Pipe inside diameter• Weld height• Gap width

Area Depth Profile• Corrosion, erosion and pitting• Maximum weld height• Maximum wear groove depth

Angle• Angle on flat surfaces

Surface Angle• Blade tip curl

• Angle between two surfaces

Missing Corner• Missing blade corners

8
8

Area

• Coating loss
• Surface area of pitting or corrosion

Multi-Segment• Total length measurement on curved orirregular surfaces

Depth Profile• Quick assessment of height or depth

Measurement Plane• With Area or Missing Corner for blade
missing corners• With Point to Line for blade edge damage• With Depth for blade tip to shroud gaps
• With Length or Point to Line for small features• With Area Depth Profile when measuring in afield of pits
• With Radius Gauge to evaluate blended
blade radii

Blade Tip Clearance• Compressor and turbine efficiency checks

Radius Gauge• Boroblending radiusMeasurement Types
This section will detail each of the measurement types available on the Mentor Visual iQ VideoProbe,suggest applications where each technique can be most effective, and provide tips and suggestions for
accurate measurement setup.

LengthMeasures the straight-line distance between two selected cursor points.

Example Applications:

3D Surface Mask:• Simple measurement of features or components

When enabled in Settings, a blue mask will highlight surface points
where planes perpendicular to the straight length 3D line between
the cursor points intersect the viewed surface.

• Indication length measurement (i.e., cracks)• M easurement of component size migration through expansion
or erosion/corrosion/wear• Determining the remaining size of wear indicators• Measuring location/zone of indications on a partBest Practices to Improve Measurement Accuracy:• L ength is a straight-line measurement. It is not suitable tomeasure the distance across a curved surface.
• W hen measuring a distance from an edge, adjust the cursor
positions such that the light blue 3D Surface Mask appears
along the edge rather than at an angle to the edge. This will
minimize error caused by measuring diagonally. Point to Line
may also be a better option in such cases.

• M ove the tip closer to make the target area as large in thecenter of the screen as possible, while keeping the cursor point
areas in focus.
• W atch for orange advisory indicators to ensure themeasurement distance is within the confidence interval.
• The zoom window can be helpful for accurate placement. It is
important to start with a crisp image so that the cursors can beplaced accurately on the indication.

• U
 se a Measurement Plane when red areas prevent proper
cursor placement or 3D noise may be affecting the result. See
the Measurement Plane section for details.

Real3D Measurement Handbook | 9

Point to Line

Measures the perpendicular distance between a line (defined by two points), and a selected point.

Example Applications:

3D Surface Mask:• Turbine blade edge damage

When enabled in Settings, a blue mask will highlight surface points
where planes perpendicular to the straight 3D line between thethird cursor point and the reference line intersect the viewed
surface.

• E stimate missing corner area using multiple point-to-line
measurements• Gap or groove width

Best Practices to Improve Measurement Accuracy:• Weld width• R eview the 3D point cloud to ensure your cursors are locatedcorrectly.
• S pace the first two cursors far apart along the reference edge.
If possible, place them on opposite sides of the indication being
measured. Placing them close together can cause error bytilting the reference line in 3D space.

• C heck the point cloud to verify that the reference line is nottilted with respect to the reference edge on the part. This isespecially important when both reference line cursors are on
the same side of and away from the third cursor.
• A lso check the point cloud to be sure the measured distance is
not at a diagonal, which can give a higher-than-actual result.
• U se a Measurement Plane when red areas prevent proper
cursor placement or 3D noise may be affecting the result. See
the Measurement Plane section for details.
• U se a Measurement Plane when measuring distance from arounded edge to determine the perpendicular distance from theedge. Position the reference cursors such that the light blue 3D
Surface Mask appears along the outer face of the rounded edge.

10DepthMeasures the distance from a reference plane (defined by three selected points) to a fourth selected point above or below the plane.

Example Applications:Best Practices to Improve Measurement Accuracy:• Blade tip to shroud gaps

• T he measurement tip should be as close as possible to theindication to increase the accuracy of measurement.

• Pits or dents from corrosion, erosion, or FOD impact• Pipe inside diameter• Weld height• Stator vane rock
• Gap width• P osition the three reference-plane cursors to maximize thecoverage of 3D Surface Mask green pixels on the reference
surface. If measuring a recessed point, use the color gradient toensure that the measurement is taken at the deepest point. If
measuring height or depth to a flat surface, try to maximize theamount of light blue shown on that surface.
• C heck the 3D point cloud view to verify that the reference
plane, indicated by a blue square, is accurately aligned with thereference surface.


3D Surface Mask:
When enabled in Settings, surface points very close to thereference plane are shown in green. Surface points the same
distance from the reference plane as the measurement result are
shown in light blue. If the result is negative, a color gradient also
highlights regions deeper than the measurement point with red
indicating the deepest points.

• T he green Surface Mask, visible when a reference plane cursor
is active, indicates points very close to the reference plane.
Adjust the cursor positions to maximize the amount of green on
the reference surface. The 3D point cloud view can also be used
to verify that the reference plane, indicated by a blue square, isaccurately aligned with the reference surface.
• A fter the third cursor is placed, the Depth Assist feature willoften automatically place the fourth cursor at the deepest
point, highest point, or on a blade edge nearby. Check theposition of the auto-placed cursor and adjust if necessary.
• E nable depth map mode in the point cloud view to bettersee surface contours and ensure that you are measuring thedesired point—often the highest or lowest on an indication—andthat the indication clearly stands out from the 3D data noise.
• T he line projected from the depth measurement point should
end near or within the triangle formed by the reference-planecursors to minimize inaccuracy due to plane tilt.
• If you must measure at a point far outside the reference
triangle, increase the size of your reference triangle tocompensate (this only applies to flat surfaces, not curved
surfaces).
• U se a Measurement Plane when measuring blade tip to shroud
clearance and red areas along the blade edge prevent proper
fourth cursor placement or 3D noise may be affecting the result.
See the Measurement Plane section for details.
Real3D Measurement Handbook | 11

Area
Measures a planar area on a surface by outlining an indication
with multiple cursor points.

Example Applications:• Missing blade corners using a Measurement Plane• Coating loss
• Surface area of pitting or corrosion• FOD impact damage

Best Practices to Improve Measurement Accuracy:• C heck the point cloud to ensure accurate cursor placement.
• W hen measuring a curved surface, reduce error by measuringmultiple smaller areas and combining the results.
• U se with a Measurement Plane to measure area and lengthsof blade missing corners. See Measurement Plane section for
details.

Multi-segment
Measures the total length along a curved or jagged path using
multiple cursors placed along the path of the indication.

Example Applications:• Total travel path of a complex crack• Total length along a curved surface

Best Practices to Improve Measurement Accuracy:• Check the point cloud to ensure accurate cursor placement.
• Spaceyour cursors as far apart as possible while following thepath of the indication to minimize the effect of 3D data noise on
the result.

12

Depth Profile

From any viewing angle, maps the perpendicular distance from a reference plane along a line between two selected points andautomatically identifies the deepest or highest point.

Example Applications:Best Practices to Improve Measurement Accuracy:• Depth of isolated corrosion or erosion pits• P osition the measurement tip as close as possible to theindication to increase measurement accuracy.

• Depth of FOD impact damage• P osition the cursors to maximize the coverage of 3D Surface
Mask green pixels on the reference surface. If measuringa recessed point, use the color gradient to ensure that themeasurement is taken at the deepest point. If measuring heightor depth to a flat surface, try to maximize the amount of light
blue shown on that surface.

• Weld height or wear groove depth• Quick assessment of surface contours

• E nable depth map mode in the point cloud view to bettersee surface contours and ensure that you are measuring thedesired point—often the highest or lowest on an indication—andthat the indication clearly stands out from the 3D data noise.
• T he green Surface Mask visible when a cursor is moved
indicates points very close to the reference plane. Adjust the
cursor positions to maximize the amount of green on thereference surface. The 3D point cloud view can also be used toverify that the reference plane, indicated by a blue square, isaccurately aligned with the reference surface.
• If the cursor turns red, this indicates improper placement.


3D Surface Mask:
When enabled in Settings, surface points very close to thereference plane are shown in green. Surface points the same
distance from the reference plane as the measurement result are
shown in light blue. If the result is negative, a color gradient also
highlights regions deeper than the measurement point with red
indicating the deepest points.

• A
 s the reference plane is determined by fitting to all thesurface data within both cursor perimeters, ensure that the two
cursors are fully positioned on the same plane of interest—not
overlapping an edge, or on offset or curved surfaces that could
cause measurement error.
• If measuring on a curved surface, such as inside a small pipe,
space the cursors apart in a direction parallel to the curvature
to keep them on the same plane. In the point cloud view, theblue reference-plane square should appear tangent to thereference surface.
• T he Depth Profile view may be used to help visualize the surface
contours along the profile slice.
• In applications seeking the deepest or highest point, Area Depth
Profile or Depth may be preferred over Depth Profile as they
automatically identify the deepest or highest point in an area.

Real3D Measurement Handbook | 13

Area Depth Profile

Sweeps a series of depth profile slices over an area defined by three cursors and identifies the profile slice having the highest or lowest
point.

Example Applications:Best Practices to Improve Measurement Accuracy:• Corrosion, erosion and pitting• P osition the measurement tip as close as possible to theindication.

• FOD impact damage• Maximum weld height including orbital welds• Maximum wear groove depth• U
 se with reference surfaces that are flat or have curvature in
only one direction, such as a straight section of a pipe. Do notuse on surfaces with complex curvatures such as a pipe elbow
or turbine blade root at the leading or trailing edge.
• W hen measuring on a curved surface, position the cursors suchthat the reference profile lines are curved. If unsure of proper
orientation, practice on a test piece of the same shape. Whencursors are properly placed, you should get a result close to zero,and most of the area should be shown in green. See images.
• If only a small line of 3D Surface Mask green is shown near thetwo reference profile lines, the cursors are likely positioned
incorrectly on a curved surface.
• T he green Surface Mask visible when moving the cursors
indicates points very close to the reference planes of the depth
profile slices. If you only have a small line of green near thetwo reference profile lines, you are likely positioning the lines
incorrectly on a curved surface. See images.


3D Surface Mask:
Each depth profile slice in the series uses a reference plane
determined from the surface orientation at the slice endpoints.
This allows curved surfaces, such as pipe walls to be followed.
When enabled in Settings, the 3D Surface Mask shows surface
points near the individual slice reference planes in green.
14• T he reference profile lines follow the surface curvature and areused to determine the reference planes for the profile slices.
Position the cursors such that the reference profile lines are fullyon the reference surface.
• U se the 3D point cloud to verify that the reference plane for the
result slice, indicated by a blue square, is accurately alignedwith the reference surface at the location of the result slice.
• T he first two cursors define the first reference profile line. The
third cursor sets the distance between the second reference
profile line and the first. The system determines the endpoints ofthe second reference profile line to match the curvature of thesurface along the first. If you have difficulty getting the second
reference profile line where you want it, you are likely not setting
up the measurement correctly with respect to surface curvature.
• T he Depth Profile view may be used to help visualize the surface
contours along the identified profile slice.

Blade Tip ClearanceA

Automatically identifies the blade and liner, maps the edge of the blade, and determines the minimum, maximum, and average
clearance within the mapped blade edge region.

Example Applications:• Compressor and turbine efficiency checks

3D Surface Mask:
When enabled in Settings, the 3D Surface Mask shows liner points
near the reference plane in green and points offset from thereference plane by either the Min or Max result distance in light
blue.

Best Practices to Improve Measurement Accuracy:
Technology Choice• Both 3DPM and 3D Stereo can be used.
• The 105° FOV of 3DPM tips allows a wider blade tip to be viewed
and measured from a given distance than 3D Stereo.
• 3D Stereo may provide better results than 3DPM in compressors
having shiny blades and liners.
• With 3DPM, a non-perpendicular view of the blade can improvedata quality by directing mirror reflections from the blade andliner away from the camera.
• The 3DPM XL4TM61105SF green tip may be unable to generate 3D
data on the liner when inserted
Setup• Position the probe tip as close as possible to the blade while
keeping the blade tip region of interest in the view.
• Position the probe tip with the optics close to the liner to give aclear view of the blade tip and gap.
• Adjust the view to avoid seeing other edges in the image
near the blade tip as they may affect the system’s ability toaccurately map the blade edge.
• If possible, adjust the tip orientation to create a visible dark
shadow on the liner side of the blade edge, which helps withblade edge mapping. Rotating the tip such that the viewing

optics are between the illumination exit point and the liner cancreate this shadowing.
• With shiny compressor blades, use Dark Boost and/or Brightness
to optimize visibility of the blade tip with minimal glare near theedge.
Checking the Reference Plane• The 3D Surface Mask should show green over most of the liner inthe vicinity of the blade tip.
• The blue rectangle should line up with the liner in the point cloudview.
• Check the 3D liner data in the point cloud view. If large anomalies
are present, adjust the tip position for a view less perpendicular
to the blade. Otherwise, manually adjust the 3 liner cursor
positions to maximize green mask coverage and improve blue
rectangle alignment.
Checking the Blade Edge Mapping• Verify that the blade edge line closely follows the blade edge inthe 2D image.
• Activate the Min and Max cursors and verify in the zoom windowthat they are accurately positioned on the blade edge.
• Check the point cloud for data quality on the blade near the tip.
If significant anomalies exist, adjust the setup and capture a newimage.
• Verify that the blade curvature is followed by the blade edge linein the point cloud view.
• Exclude areas near the ends of the mapped edge that are
affected by 3D noise, missing corners, etc., from the analysis bymoving either bounding cursor away from the edges.
• The algorithm applies fitting and filtering to reduce the impact ofsmall gaps or noise in the blade 3D data. This may result in theblade edge line being slightly offset from the blade edge data inthe point cloud view where the gaps or noise exist.

Real3D Measurement Handbook | 15

Blade Tip Clearance Advisory Messages
Functionality Notes

Advisory System Checks:• The blade and shroud can have any orientation in the image.

The system looks for several common issues that may degrade
accuracy.

• Not intended for use with honeycomb liners, turbine blades
having outer shrouds, or blades that have irregular tip
geometries by design or due to rubs.
• The clearance is measured from a reference plane determinedfrom the 3 reference plane cursor locations. These cursors canbe manually re-positioned.
• The algorithm maps the blade edge using the “Normal” 2D
image (HDR images are not used). 3DPM pattern images may
also be utilized where edge contrast is low in the normal 2D
image.
• The pixels near the blade edge must be brighter than those justoff the blade edge for successful mapping.
• The Max measurement point is visually differentiated from the
Min measurement point by having a larger inactive cursor size.
• The Min and Max cursors cannot be manually re-positioned.
• The two bounding cursors, one at each end of the mapped
blade edge, can be moved to exclude end portions from themin/max/average analysis.
• Long touch any shroud cursor to return all 3 shroud cursors totheir automatically-chosen positions.
• Long touch either bounding cursor to return it to its
automatically-chosen position.
• Use Auto Repeat to improve efficiency when making repetitive
Blade Tip Clearance measurements.

16• Shroud 3D data quality may be reducing accuracy:
The reference plane may not be accurately aligned to the liner inthe vicinity of the blade tip due to excessive 3D noise, large gaps
in 3D data, or insufficient liner visibility in the view.
• Blade 3D data quality may be reducing accuracy:
Excessive 3D noise or large gaps in 3D data exist near the bladeedge• Move closer to target or move cursors for better results:
The system may not be capable of accurately measuring a gapof the indicated size from the current tip-to-target distance.
• To improve accuracy, capture image with tip optics closer tothe shroud:
The viewing perspective may not allow the true blade edge to beaccurately mapped and measured.

Surface Angle

Measures the angle between a reference plane, defined by three points, and an angle plane determined by fitting the surface within the
fourth plane cursor.

Example Applications:Best Practices to Improve Measurement Accuracy:• Turbine blade tip curl

• P
 osition the measurement tip as close as possible while keeping
enough reference surface in the view for establishing thereference plane.

• Weld toe angle• Angle between two surfaces.

3D Surface Mask:
When enabled in Settings, surface points very close to thereference plane are shown in green, and surface points very close
to the angle plane are shown in light blue.

• P osition the three reference-plane cursors to maximize
the coverage of 3D Surface Mask green pixels on thereference surface.
• C heck the 3D point cloud view to verify that the reference
plane, indicated by a blue square, is accurately aligned with thereference surface.
• In the 3D point cloud view, verify that the angle plane, indicatedby the light blue 3D Surface Mask and the angle line, is tangent
to the surface at the desired measurement point.
• T he fourth cursor is relatively small to allow it to be placed near
the tip of curled turbine blade corners. This small fitting area
does make Surface Angle somewhat sensitive to 3D noise on
the angle-plane surface. In applications where both surfaces
are large relative to the size of the fourth cursor, accuracy canbe improved by placing the Measurement Plane on the angleplane surface, in which case the Surface Angle result is the angle
between the reference plane and the Measurement Plane.

Real3D Measurement Handbook | 17

AngleMeasures the 3D angle between two lines defined by three points.

Example Applications:• Angle on flat surfaces• With Measurement Plane to measure dilution chute erosion angle

3D Surface Mask:
There is no 3D Surface Mask with Angle.

Best Practices to Improve Measurement Accuracy:• A void placing cursors very close together to reduce the impact
of noise in the 3D data on the result.
• C heck the 3D point cloud view to verify that the plane
containing the measurement points, indicated by a blue square,is accurately aligned with the desired surface.

Missing Corner

Measures the area and edge lengths of a missing blade cornerwith one point designating the position of the tip of the missing
corner and up to 23 additional points placed along the brokenedge. Requires a Measurement Plane placed on the surface of theblade near the missing corner.

Example Applications:• Turbine blade missing corners

3D Surface Mask:
When enabled in Settings, surface points very close to the
Measurement Plane are shown in green. Surface points near the
projected missing edge lines are shown in light blue

Best Practices to Improve Measurement Accuracy:• A djust the Measurement Plane cursor positions to maximize
coverage of the green 3D Surface Mask on the blade near the
missing corner.
• A djust the Missing Corner cursors to align the dashed extension
lines with the blade edges in the 2D image.

18

Radius Gauge

Creates a 3D circle of a user-designated size to enable a visual comparison against the shape of a surface to be evaluated inaccordance with a known radii (or diameter).

Example Applications:Best Practices to Improve Measurement Accuracy:• Gas Turbine boroblend: scallop or tip blend.

• B est suited in conjunction with long range Yellow (forwardfacing) or Green (side facing) 3D Phase Measurement tips.

3D Surface Mask:• C
 an be used with Measurement Plane in order to enableradii check on edges of components such compressor blade
aerofoils or indeed when the surface is curved and a ‘best fit’plane is considered appropriate.

When used without a Measurement Plane, a best-fit plane isdetermined using points inside the circle on the same surface as
the center cursor. When enabled in Settings, points near the bestfit plane are shown in green with the exception of points in thevicinity of the circle, which are not masked in order to increase thevisibility and position of the circle.

• N ote that the circle line visibility in the point cloud view varies as
it crosses between the near and far sides of the surface.

Real3D Measurement Handbook | 19

Measurement PlaneA

Measurement aid used in conjunction with other measurement types to allow the placement of cursors in red areas where no 3D data ispresent or where noise in the 3D data may be reducing measurement accuracy. This is accomplished by mathematically extending themeasurement plane into 3D space.

Example Applications:• With Area or Missing Corner to measure blade missing corners• With Point to Line for blade edge damage• With Depth for blade tip to shroud gaps
• W
 ith Length or Point to Line for small features when unable toget closer• W ith Area Depth Profile when measuring a field of pits on aflat surface• W ith Depth Profile when you cannot fit the cursors fully on a flat
reference surface• With Radius Gauge to assess boroblend edge radii

Effect of a Measurement Plane on othermeasurement types:• Length, Point to Line, Multi-Segment, and Area: All cursors
are projected onto the Measurement Plane, and the result is
computed using the projected positions on the plane.
• D epth: The first three cursors select individual surface points aswith a normal Depth measurement. Only the fourth is projected
onto the Measurement Plane.
• Depth Profile: The Measurement Plane is used as the reference
plane, so the Depth Profile cursors may overlap edges or
be in red areas. The result is the height or depth from the
Measurement Plane. Use only with flat reference surfaces.
• Area Depth Profile: Both reference lines are positioned on the
Measurement Plane allowing them to pass through red areasor surface pits without affecting the profiles taken between
the reference lines. The result is the height or depth from the
Measurement Plane. Use only with flat reference surfaces.
• Angle: All three cursors are projected onto the Measurement Plane.
• S urface Angle: Only the fourth cursor is projected onto the
Measurement Plane. The first three cursors still separately
define the reference plane.
• M issing Corner: Requires prior placement of the Measurement
Plane, and all cursors are projected onto the Measurement Plane.
• R adius Gauge: The Radius Gauge circle is placed on the
Measurement Plane.
• Only one Measurement Plane can be used on an image.
• If a Measurement Plane is present, all other measurements use
it regardless of the order in which they were placed.

20Measurement Plane Guide Lines

Guide Lines are shown in the point cloud views when using a
Measurement Plane with Length, Point to Line, Multi Segment, orArea. They are shown as black lines that are perpendicular to the
Measurement Plane and extend from the cursor locations on the
Measurement Plane to surface points straight above or below thecursor locations. Spheres are shown where Guide Lines intersect
the surface.

Example Applications:• Edge damage on rounded turbine blade or vane edges• Turbine vane platform to shroud gaps
• Edge radius estimates• Gap width• Any in-plane dimensions between points not on the same planeBest Practices to Improve Measurement Accuracy:• A djust the cursor positions until the Guide Lines and surface
spheres appear in the point cloud view at the desired locations.
• U se when measuring on rounded edges and an in-planemeasurement like that obtained using an optical comparator
is desired.The conventional Point to Line measurement of arounded leading edge indication in the lower left image is ona diagonal and therefore gives a larger result than would beobtained using an optical comparator.The same indication ismeasured in the top left image using a Measurement Plane
with Guide Lines to remove the angle.
• E nsure that the rounded edge is angled toward the probe tip
and fully visible rather than angled away from the tip.
• C annot be used when the 3D data does not extend all the way
to the edge of the surface.
• S hould be used to guide cursor positioning on rounded edges
oriented toward the probe tip, especially when the EVA exceeds
about 15°. The rounded edge is off the measurement plane, so
unless the EVA is low, the cursors cannot be placed properly
using only the 2D image.

Conventional Measurement on a Diagonal

Real3D Measurement Handbook | 21

Measurement Plane Examples
Turbine blade missing corner dimensions:• Use a Measurement Plane with Missing Corner or Area.
• P osition the probe tip according to recommendations in the
Measurement Plane EVA Advisory section.
• P lace the Measurement Plane on the face of the blade near the
missing corner. Maximize the green surface mask near the areaof missing material.
• P lace a Missing Corner or Area measurement with one cursor oneach remaining corner, one cursor out in space where the cornerused to be, and as many as are needed to follow the broken edge.
• A fter pressing “Done”, adjust the cursors so that the extended
lines line up with the blade edges near the missing corner region.
• T he missing area, missing edge dimensions, and the corner
angle are all provided eliminating the need for additional
measurements. This measurement data field can be moved
into position as desired.

Turbine blade edge indication:• U se a Measurement Plane with Point to Line when 3D data along
the blade edge is missing or noisy.
• P lace the Measurement Plane on the face of the blade near
the indication and maximize the green surface mask near theindication and surface edge.
• A dd a Point to Line measurement with the first two cursors
placed on the edge of the blade and the third at the inner edgeof the indication.

22

Measurement Plane Examples
Turbine blade tip to shroud clearance:• Place the first three Depth cursors on the shroud.

• U se a Measurement Plane with Depth when 3D data at the edgeof the blade is missing, noisy, or drawn down and back toward
the shroud as shown in the lower right image.

• P osition the fourth Depth cursor at the edge of the blade in the
2D image. This cursor is projected onto the Measurement Plane,
so it may appear slightly off the edge in the point cloud due tomissing or noisy 3D data at the edge.

• P osition the probe tip low to the shroud so that you can see
back under the blade. The left image below is captured from
too far above the shroud.
• P lace the Measurement Plane on the face of the blade near
the desired measurement point. Too much spacing between
the cursors near the blade edge can increase error due toblade curvature. Look at the green surface mask for cues of thiscurvature near the area to be measured.



Real3D Measurement Handbook | 23

3D Stitching (3DS)
A

Composite image examples captured using 3D Phase Measurement
Inspect, interrogate (measure) and report more of the scene. Ability to combine up to ten images (3D Phase or 3D Stereo) to create acomposite image is now possible on the device. Reduce measurement uncertainty by capturing higher quality images and performing
measurements on the overall composite image.
3DS can be undertaken during a given inspection or from recalled images captured earlier. Images must however be captured from thesame probe and tip in order to successfully stitch.

Example Applications:

Setup• Large defect measurement assessment• Position the probe tip as close as possible to the target surface.

• E stablishing defect location relative to fixed positions on thecomponent• Images must have at least 50% overlap. Too little overlap often
results in failed or inaccurate stitching.

• Creation of stitched image for reporting purposes• Surface must have unique details that look similar from one
image to the next.

Disclaimer:• Surfaces that have a shiny or reflective appearance thatchanges as the probe tip moves position can be problematic.
Increasing overlap can help.

The quality of the 3DS process is dependent on a number offactors. You, the User, are responsible for checking the quality ofboth individual and composite images to ensure the best possible
outcome. Please refer to the General Guidelines section in thisdocument to learn more.

• Avoid excessive (c.20°) rotation steps between image captures.

The factors that have the greatest effect on 3DS are:• Clean data helps – minimize MTD. Use Green or Yellow 3DPM tip
where possible.

• Distance from target• Avoid excessive (c.30%) magnification steps between image
captures.

• Visual features contained within the scene• Always check registration or stitching quality before proceeding
and measuring.

• Image overlap

Checking Registration Accuracy• Target material composition• During the capture and subsequent stitching of images, it ispossible to intermittently check the registration or quality of stitch
before proceeding and capturing more images or subsequent
measurement assessment.

Best Practices to Improve 3DS Accuracy:
Technology Choice• Both 3DPM and 3D Stereo can be used.
• The 105° FOV of 3DPM tips allow a wider scene to be viewed andmeasured from a given distance than 3D Stereo (50 or 60° FOV
dependent on tip used).
• 3D Stereo may provide better results than 3DPM in compressors
having shiny blades and liner.

24• This is an important process to ensure accuracy ofmeasurements on stitched images.
• Watch surface details while using ‘Next/Previous Image’• If well registered, surface details will move very little
between images• If poorly registered, details will shift.

3D Stitching (3DS)

Checking registration of individual
imagesThis example shows good registration.

The example shows poor image
registration of a compressor blade

Signs or indicators of poor image registration are:• Clear gaps between images• Surfaces offset from one another• Surface features are not in the same location when switching
between images.

3D Stitching – Orange Mask
Orange mask is shown when the device is presenting individual 2D images. The mask represents the areas of the image that do notcontribute to overall composite point cloud and are not used for measurement.

All three images are used to generate the composite stitched image but some areas (shaded orange) are discarded and not used. The
primary image contains the least orange masked area.
Selection of an individual 2D image and subsequent measurement may result in displaying an orange measurement cursor. This cursor
highlights it being derived from a different image within that stitched image set. Note: normal measurement cursors are coloured green(when inactive). See above.

Real3D Measurement Handbook | 25

3D Stitching (3DS)
3D Stitching – Occluded Cursors
On surfaces with significant steps, some parts of the surface may be visible in one image but hidden by a closer surface in a different image.
When a cursor is placed on a surface point that is occluded by a closer surface in the current 2D image, the cursor is shown in orange
and a message is displayed.
Saving of full screen 2D images is disabled when stitching to reduce risk of misinterpretation of the position of occluded cursors on the3D surface. See images below.

Perspective Lines and Tip Model (not exclusive to 3D Stitching)
These are only shown when a measurement is present and ‘full image’ enabled in order to reduce visual intrusiveness. They can be
activated/deactivated within Settings > Measurement Annotation.
With 3D Phase images, a tip model can be enabled via ‘Options’ 2nd level soft key. This provides visual reference of the probe tip in
relation to the target surface.

26

Measurement Accuracy Data

The measurement accuracy curves on pages 19-20 were created from trained third party test results
using 6.1 mm diameter 3DPM and 3D Stereo (3DST) on a Mentor Visual iQ under controlled conditions witha matte finish test block. They should be interpreted as system capability under ideal conditions. Actual
results vary with application, surface conditions, equipment condition, and user expertise.

Pt-Line Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.071" Edge IndicaHon Feature

0.001
0.001

0.50%
0.5%

00

0.00%
0.0%

0.6
0.6

3DPM

0.8
0.8

MTD (in) 3DST

11

1.2
1.2

MTD (inch)

Average Absolute Error (%)

0.10.1

1.50%
1.5%

0.075
0.075
0.05
0.05

1.00%
1.0%

0.025
0.025

0.50%
0.5%

00

5

5

10

15

10

15

20

25

20

25

MTD (mm)

30

30

0.00%
0.0%

MTD (mm)

9.00%
9%
6.00%
6%

0.002
0.002

3.00%
3%

0.001
0.001

0.2
0.2

0.4
0.4

0.6
0.6

0.8
0.8

MTD (in)

11

MTD (inch)

1.2
1.2

0.00%
0%

Average Absolute Error (%)
Average Absolute Error (mm)

3DST

0.003
0.003

00

0.2

0.2

0.4

0.6

0.8

1

3DPM 0.6
3DST
0.4
0.8
MTD (in)

1

1.2

1.2

5.00%
5%

0.075
0.075

4.00%
4%
3.00%
3%

0.05
0.05

2.00%
2%

0.025
0.025
00

0.00%
0%

MTD (inch)

0.10.1

1.00%
1%
5

5

10

10

15

15

20

20

MTD (mm)

25

25

30

30

35

35

0.00%
0%

MTD (mm)

Pt-Line Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.037” (0.94 mm) Missing Corner Feature

3DST

3DPM

0.004
0.004

00

1.00%
1%

Accuracy curve for point to line measurement of an edge ding.

Average Absolute Error (%)

3DPM
Average Absolute Error (in)Average Absolute Error (inch)

Accuracy curve for length measurement of a crack.

2.00%
2%

0.001
0.001

3DPM

3DST
3DPM

0.10.1

3DST

9.00%
9%

0.075
0.075

6.00%
6%

0.05
0.05

3.00%

3%

0.025
0.025

00

0.00%
5

5

10

10

15

20

25

15 MTD20
25
(mm)

30

30

35

35

0%

Average Absolute Error (%)

0.4
0.4

3.00%
3%

0.002
0.002

Average Absolute Error (%)

0.2
0.2

4.00%
4%

Average Absolute Error (%)

1.00%
1.0%

5.00%
5%

0.003
0.003

Average Absolute Error (%)

0.002
0.002

3DST

Average Absolute Error (%) Average Absolute Error (%)

1.50%
1.5%

0.003
0.003

3DPM

0.004
0.004

Average Absolute Error (in)Average Absolute Error (%)

3DST

Average Absolute Error (mm)

3DPM

0.004
0.004

Average Absolute Error (in)3DST

Pt-Line Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.071” (1.8033DPMmm) Edge Ding 3DST
FeatureAverage Absolute Error (mm)3DPM

Average Absolute Error (%)
AverageAbsolute
AbsoluteError
Error (mm)(%)
Average
Average Absolute Error (inch)

Averaged Over 0° to 50° Viewing Angle0.21” (5.33 mm) Long Feature

Average Absolute Error (mm)Average Absolute Error (mm)Average Absolute Error (inch)

Length Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
Length Error Long
vs. MTDFeature
0.21" (5.33mm)

MTD (mm)

Accuracy curve for point to line measurement of a missing corner.

Note: Measurement Planes were not used in this testing
but would likely improve the results on some features.
Real3D Measurement Handbook | 27

Depth Proﬁle Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.015" Deep Feature

0.4

0.2

0.4
3DPM

0.6

MTD (in)

0.8

0.6
3DST

0.8

MTD (inches)

0.10.125.00%
25%
20.00%
20%

0.075
0.075

15.00%
15%

0.05
0.05

10.00%
10%

0.025
0.025

00

5.00%
5%
5

10

5

10

15

MTD (mm)

20

15

20

0.00%
0%

MTD (mm)Depth Error vs. MTD
Averaged Over All Viewing Angles
0.097" Tip to Shroud Feature

5%

5.00%

0.004
0.004

4.00%

0.003
0.003

3.00%

0.002
0.002

2.00%

0.001
0.001

1.00%

4%
3%
2%
1%

00
0.2
0.2

0%

0.00%
0.4

0.6

0.4 3DPM
0.6

0.8

1

1.2

0.8 3DST
1

1.2

MTD (in)

1.4

1.4

MTD (inch)

0.125
0.125

5%

5.00%

0.1

0.1

4.00%

0.075
0.075

3.00%

0.05
0.05

2.00%

0.025
0.025

1.00%

00

4%
3%
2%
1%

5

5

10

10

15

15

20

20

25

25

MTD (mm)

MTD (mm)

30

30

35

35

40

0%

0.00%

40

Average Absolute Error (%)

Average Absolute Error (in)

3DST

Accuracy curve for depth measurement of a tip to shroud distance.

28

0.2

0.4

0.6

0.8

0.4 MTD (in) 3DST
0.6
3DPM

25.00%
25%
20.00%
20%

0.075
0.075

15.00%
15%

0.05
0.05

10.00%
10%

0.025
0.025

00

0%

0.8

MTD (inch)

0.10.1

0.00%

5.00%
5%
5

10

5

15

20

10 MTD (mm) 15

20

0.00%
0%

MTD (mm)Depth Proﬁle Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.019" High Weld Feature

Average Absolute Error (%)

3DPM

0.005
0.005

0.2

Accuracy curve for depth profile measurement of a pit or dent.

Average Absolute Error (%) Average Absolute Error (%)
Average Absolute Error (mm)Average Absolute Error (inch)

Depth Error vs. MTD
Averaged Over All Viewing Angles
3DPM
3DST
0.097” (2.464mm) Tip to Shroud
FeatureAverage Absolute Error (mm)Average Absolute Error (inch)
Average Absolute Error (mm)Accuracy curve for depth measurement of a pit or dent.

00

5.00%
5%

Average Absolute Error (%)

0.00%
0%

10.00%
10%

0.001
0.001

Average Absolute Error (%)

0.2

15.00%
15%

0.002
0.002

Average Absolute Error (%) Average Absolute Error (%)

00

5.00%
5%

20.00%
20%

0.003
0.003

Depth Profile Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.019” (0.483mm) High Weld3DST
Feature
3DPM
3DPM

0.004
0.004

3DST

20%

20.00%

0.003
0.003

15.00%

0.002
0.002

10.00%

0.001
0.001

5.00%

00

0.00%

15%
10%
5%

0.2

0.2

0.4

0.6

0.8

0.43DPM0.6
0.8
3DST
MTD (in)

1

1

1.2

1.2

MTD (inch)

0.10.10%

20.00%
20%

0.075
0.075

15.00%
15%

0.05
0.05

10.00%
10%

0.025
0.025

5.00%
5%

00

5

5

10

10

15

15

20

20

MTD (mm)

MTD (mm)

25

25

30

30

0.00%
0%

Average Absolute Error (%)

10.00%
10%

0.001
0.001

25.00%
25%

Average Absolute Error (%)

15.00%
15%

0.002
0.002

3DST

Average Absolute Error (%) Average Absolute Error (%)

20.00%
20%

Average Absolute Error (in)

0.003
0.003

Average Absolute Error (mm)25.00%
25%

3DPM

0.004
0.004

Average Absolute Error (in)

3DST

Depth Profile Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
3DPM
3DST
0.015” (0.381mm) Deep Feature

Average Absolute Error (mm)

3DPM

0.004
0.004

Average Absolute Error (%)
Average Absolute Error (%)
Average
Absolute Error (%) Average
Absolute Error (%)
Average
Absolute
Error (inch)
Average Absolute Error (mm)Average Absolute Error (in)Depth Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.015” (0.381mm) Deep Feature
3DPM
3DST

Average Absolute Error (mm)Average Absolute Error (mm)Average Absolute Error (inch)

Depth Error vs. MTD
Averaged Over 0° to 50° Viewing Angle
0.015" Deep Feature

Accuracy curve for depth profile measurement of weld height.

Specifications

Measurement Tip Optic Specs and Part Numbers for Mentor Visual iQ
Mentor Visual iQ 4.0 mm Tips

3D Stereo Measurement and Stereo Measurement Tips
Part No.

Color

FOV (deg)

DOF mm(in)

TM405555FG

Black

55/55-FWD

5-inf(.20-inf)

TM405555SG

Blue

55/55-SIDE

4-inf(.16-inf)

Mentor Visual iQ 6.1mm Tips
3D Phase Measurement Tips
XL4TM61105FG

Black

105-FWD

8-250(.31-9.84)

XL4TM61105SGBlue

105-SIDE

7-250(.27-9.84)

XL4TM61105FF

Yellow

105-FWD

15-inf(0.59-inf)

XL4TM61105SN

Red

105-SIDE

2-20(.08-.79)

XL4TM61105FN

Orange105-FWD

3-120(.12-4.72)

XL4TM61105SF

Green

105-SIDE

15-inf(.59-inf)

3D Stereo Measurement and Stereo Measurement Tips
XLG3TM616060FG

Black

60/60-FWD

4-80(.16-3.15)

XLG3TM615050SG

Blue

50/50-SIDE

2-50(0.8-1.97)

Mentor Visual iQ 6.2mm Tips

3D Stereo Measurement and Stereo Measurement Tips
TM626060FN

Black

60/60

4-80

(0.16-3.15)

TM626060SN

Blue

60/60

4-80

(0.16-3.15)

Mentor Visual iQ 8.4mm tips

3D Stereo Measurement and Stereo Measurement Tips
XLG3TM846060FG

Black

60/60-FWD

4-50(.16-1.97)

XLG3TM846060SG

Blue

60/60-SIDE

4-50(.16-1.97)

Stereo and 3D Stereo use the same Optical Tip Adapters

Real3D Measurement Handbook | 29

Glossary
3D Data Mask – Shows red and yellow pixel masks. See "Red
Mask on Image" and "Yellow Mask on Image" for details.
3D Perspective Lines – Dotted blue lines showing the four
corners of the tip field of view in the full image point cloud tohelp the user understand and improve tip orientation relative
to a surface. May be shown or hidden via the settings menu.
3D Phase Measurement – A measurement technologythat projects line patterns on an object via a series ofLEDs. Measurements are calculated using the concept ofphase shift analysis combined with proprietary processing
technology.
3D Point Cloud – A 3D graphical representation of the surface
being inspected on which lines and spheres are added toshow measurements made on that surface. The 3D point
cloud can be rotated and viewed from multiple angles andperspectives. It allows an inspector to check measurement
setup and initiate and edit cursor placement points.
3D Stereo Measurement – Uses the same optical principles
and tip optics as Stereo Measurement and combines thesewith the ability to create, manipulate and analyze a 3D Point
Cloud representation of measurement data.
3D Surface Mask – Colored semi-transparent masking of
surface points in the 2D image and point cloud views during
3DPM or 3D Stereo measurement that helps guide proper
cursor placement.
Active Cursor – The cursor currently being manipulated,indicated by a blue circle.
Advisory Message – “For best results the reference cursors
should be on the same plane” – In depth profile measurement,
indicates the reference cursors are not on the same plane.
Advisory Message – “Move closer to target or move cursors
for better results” – Indicates that the measurement is too
small to be reliable at the current tip to target distance. Can
be remedied by moving tip closer to the indication or selecting
larger measurement area.
Auto-Repeat – Setting Auto Repeat in the measurement
menu to “On” remembers all measurements performed on
the current image along with the current measurement view.
Upon subsequently pressing the 3DPM Capture (from live) or
Stereo (from Freeze Frame) soft keys, these measurements will
be automatically performed on the newly captured image.
This feature improves efficiency when making repetitive
measurements.
CSV – Comma separated value, used for point cloud file data
export. Can be opened in a CAD package.
Dark Boost – Dark Boost is a live video processing function
which digitally brightens darker areas in scenes with brightforeground surfaces, or glare, without over-exposing or
degrading the contrast of more uniform scenes.

30

Depth Assist – Feature wherein the system searches thesurface data in the vicinity of the first three cursors of a Depth
measurement and automatically places the fourth cursor
at the deepest point, highest point, or a point on a blade tip
saving the user the time of locating those points manually.
Depth Map – 3D point cloud viewing mode in which either
the tip to target distance (full image) or the perpendiculardistance from the measurement reference plane(measurement image) is color coded to provide better
understanding of 3D data noise levels and surface contours.
Depth Profile View – Alternative 2D view of depth profile along
a selected depth profile line.
FOD – Foreign Object Damage.
Full Point Cloud – Shows all measurements and surface data.
The depth map indicates the distance from the measurement
tip to the surface.
Guide Lines – Lines shown in the point cloud views when usinga Measurement Plane with Length, Point to Line, Multi Segment,
or Area to help the user position cursors to align with out-ofplane surface points.
Image Brightness – As it relates to a video borescope is acombination of several components, not just available light• For live video, the image brightness control adjusts thebrightness set point for the camera’s auto gain andexposure control processing• For still images, the image brightness control digitally adds
or subtracts an offset from the image’s RGB values
InspectionWorks Connect – Remote collaboration tool
allowing live remote viewing of inspection video, two–waychat and annotation. Can be activated directly on the Mentor
iQ handset.
Inactive Cursor – Cursors not currently selected, indicatedby a green circle. Insight for where data can be pushed andremeasured by SMEs.
Inspection Manager – PC–based re-measurement tool for
visual inspection images.
Measurement Point Cloud – Shows only the active
measurement and surface data in its vicinity. The depth map
indicates the perpendicular distance of the surface points
from the measurement’s reference plane.
Missing Corner – The corner of a turbine blade that has beenbroken off usually by an object passing through the turbine.
MTD – Maximum target distance. Identifies the distance of thefurthest cursor point in a given measurement from the tip of
the probe.
Noise in the Point Cloud – Artifacts in the 3D data notrepresentative of true surface geometry. Noise is generally
reduced by moving the tip closer to the target surface orchanging angle of approach to reduce reflections.

Orange Outline Around Measurement Results and MTD
Value – Indicates that the measurement is too small to bereliable for the current tip to target distance. Can be remediedby moving tip closer to measurement or selecting larger
measurement area.
Probability of Detection (POD) – “POD is the probability that aflaw of a specific type will be detected by a given techniquegiven the flaw exists in the material.” Bill Prosser, NASA
You may ask, “What is Waygate Technologies’ POD on the
Mentor Visual iQ (MViQ) VideoProbe™? And, how will it help me
during inspections and indication analysis?”
In essence, POD is a combination of technologies which allow
for the transformation of a white light image into one which
will facilitate assessing the health of the visual surface, provide
additional information about a surface’s condition, and if& when an indication, or “flaw”, is detected these tools areavailable to provide greater precision and accuracy when
deploying Real3D™ Phase and Real3D Stereo Measurement both of which provide an XYZ pivotable point cloud foranalysis.
Profile Slices – Paths along the surface between the reference
profile lines in an Area Depth Profile Measurement that map
the perpendicular distance between the surface points andthe reference surface.
Projected Plane Measurement – The use of a Measurement
Plane in combination with another measurement type tomathematically project the plane of a surface over the entire
image and measure on that plane.
Red Filled Cursors on Depth Profile – Indicates cursor is not
on a flat surface or not on the same plane. Cursor must be
repositioned for accurate measurement.
Red Mask on Image – Indicates surface data in this area is notavailable for measurement. Moving closer or adjusting viewing
orientation may reduce red mask area.
Reference Line – In a point to line measurement, the first two
cursors, placed on unaltered surface points, define a straightreference line in 3D space from which the distance to the third
cursor point is measured.

Reference Profile Line – Area Depth Profile lines set by themeasurement cursors which follow the surface contours andare used to determine the area and reference planes for the
profile slices.
Reference Surface – Unaltered part surface to be used as areference for various measurements.
Result Slice – The Area Depth Profile profile slice that includes
the highest or lowest point and is shown on the image and in
the point cloud.
Signal Strength Range Guide – Visual aid displayed whenviewing live video with a 3DPM tip attached to indicate thesystem’s ability to achieve sufficient brightness with the tip
LEDs for a high-quality scan. Increasing the number of bars bymoving closer to the target will increase 3D data quality andmeasurement accuracy.
Surface Mask - One of several masks coloring pixels ona surface with various color gradients to indicate various
surface contours or distances between cursors.
Yellow Mask on Image – With 3D Phase Measurement,
indicates surface data may be of low quality formeasurement. The potential for reduced accuracy may exist,
especially for depth or small measurements. Yellow mask
areas are often caused by surface to surface reflections.
Changing the probe orientation to make such reflections
bounce away from the probe tip may improve data quality
and reduce or eliminate yellow mask areas.
3DPM Save Format –•PMap – Original projected pattern images are embeddedin the saved image file and fully re-processed to generate
new 3D data when re-measurement is performed on
the recalled image. Generally used for development andtroubleshooting purposes.

•

ZMap – Computed 3D surface data is embedded in the
saved image file and used when re-measurement isperformed on the recalled image. Gives smaller files thanPMap and is recommended for most users.

Reference Plane – The plane, defined by three or more points
on a reference surface, from which the perpendicular distanceto other surface points is computed. A blue square indicatesthe reference plane position in the measurement image 3D
point cloud view.
Note: A reference plane is calculated as flat, even if
the surface the plane rests on is not flat. This is apotential source of error.

Real3D Measurement Handbook | 31

Waygate Technologies
721 Visions Drive
Skaneateles, NY 13152
315-554-2000
waygate-tech.com*Denotes a trademark of Baker Hughes. All other marks
are the property of their respective owners.
© 2024 Baker Hughes. All rights reserved.
GEA31907B

01/2024bakerhughes.com