My Document - Stemmer Imaging
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1. 3 Introduction noiscuccoedoaieeibiekesencuteleeeidds 4 Profile Tools 5 FBSEUIE POIDS sesiis ikre ree nioan eile LE 5 2 AR GQ Ee 7 Gap and Flush Algorithm 8 Groove Algorithm LLLLLLLLL 12 SETID AICONLIO ua usto nee crt tur EDEESRE ETUDES Der 16 Strip Start and Terminate Conditions 19 Strip Step Edge Definitions 21 Part TOONS A 23 OMe AICOUCITG a6 0255e65 0 coh anidre rone sues 22 Opening Algorithm 2 lt cccecescsececaesanecasacuc 25 SUE Pe Obl UW gee ae eee oe yes baneeseeseceess 28 Common Parameters 30 Blasco M 30 eucPBr IS 31 izle RR 31 Gocator Measurement Tool Technical Manual Introduction Several of LMI s measurement tools use complex algorithms to find features and then return measurements This documentation describes the algorithms used by the following tools profile tools e Gapand Flush e Groove e Strip And the following whole part tools e Hole e Stud e Opening Gocator Measurement Tool Technical Manual Profile Tools Feature Points Many profile measurements involve estimating the locations of feature points and then making comparisons between the feature points The following types of points can be identified Point Type Examples Top Finds the2. Gocator Measurement Tool Technical Manual Version 3 6 5 33 Revision A USER MANUAL Copyright Copyright 2014 by LMI Technologies Inc All rights reserved Proprietary This document submitted in confidence contains proprietary information which shall not be reproduced or transferred to other documents or disclosed to others or used for manufacturing or any other purpose without prior written permission of LMI Technologies Inc No part of this publication may be copied photocopied reproduced transmitted transcribed or reduced to any electronic medium or machine readable form without prior written consent of LMI Technologies Inc Trademarks and Restrictions Gocator is a registered trademark of LMI Technologies Inc Any other company or product names mentioned herein may be trademarks of their respective owners Information contained within this manual is subject to change This product is designated for use solely as a component and as such it does not comply with the standards relating to laser products specified in U S FDA CFR Title 21 Part 1040 Contact Information For more information please contact LMI Technologies LMI Technologies Inc 1673 Cliveden Ave Delta BC V3M 6V5 Canada Telephone 1 604 636 1011 Facsimile 1 604 516 8368 www lImi3D com Gocator Measurement Tool Technical Manual Table of Contents Copyright eeeseeeee ee eee 2 Table of Contents
3. LI a e e e e e e e e e 1 Valley points 1 Find the valley points The algorithm derives search parameters from the user settings to prevent noise from triggering false detections When detecting multiple grooves an adaptive algorithm is used to ensure that candidate grooves are approximately the same scale 2 Left peak 3 The right peak is rejected by ee o9 Z algorithm Groove candidate is rejected e o 9 1 Valley points The valley points of open grooves may not be visible or may fall outside of the measurement region Voids in the data regions with no profile data between pairs of valid points are detected A valley point is added midway between the pair of valid points The Z position of the valley point is either the minimum groove depth below the lower of the corners or the bottom edge of the measurement region The algorithm then proceeds as if to find a U shaped groove e 9 9 mnnwdh e 9 3min Width Min depth o Added Valley point based on min depth Added Valley point based On measurement region The actual groove bottom is calculated differently for different shapes For a V shaped groove a line is fitted to the sides of the valley points starting from the corners up to but not including the valley point The groove bottom is the intersection of the left and right lines Line fitting is used such that an accurate groove bottom can be found even when the real bottom is not visible
4. Surface Line Setting the value to 0 causes the algorithm to try to detect an edge in every missing data section Data Void Width Gocator Measurement Tool Technical Manual 10 Parameter Minimum Depth Surface Width Surface Offset Nominal Radius Description Illustration Defines the minimum depth before an opening could be considered to have a potential edge The depth is the perpendicular distance from the fitted surface line Fitted Surface Line d Minimum Depth The width of the surface area in which laser data is used to form the fitted surface line This value e e should be as large as the surface allows Surface p Fitted Surface Line The distance between the edge region and the surface region Setting a small value allows the e edge within a tighter region to be detected CT However the measurement repeatability could be affected if the data from the edge are considered as part of the surface region or vice versa A rule of thumb is to set the Surface Offset equal to the Nominal Radius Surface offset Fitted Surface Line The radius of the curve edge that the algorithm uses to locate the edge region The algorithm e searches for a start position in which the remaining so data most resemble a circle of the specified nom inal radius Edge Region Fitted Surface Line Fitted Circle Gocator Measurement Tool Technical Manual 11 Parameter Edge Angle Edge Type
5. and right sides of the groove See algorithm section below for more details Left Groove s left corner Right Groove s right corner Specifies how a groove is selected when there are multiple grooves within the measurement area Maximum Depth Groove with maximum depth Index from The Left 0O based groove index counting from left to right Index from the Right 0 based groove index counting from right to left 0 based groove index Minimum depth for a groove to be considered valid Minimum width for a groove to be considered valid The width is the distance between the groove corners Maximum width of a groove to be considered valid If set to 0 the maximum is set to the width of the measurement area See Decisions page 30 Gocator Measurement Tool Technical Manual 15 Parameter Description Region The measurement region defines the region in which to search for the groove For a stable measurement the measurement region should be made large enough to cover some laser data on the left and right sides of the groove See Regions page 31 Sides of the Groove Output See Output Filters page 31 Strip Algorithm A strip is a flat region bounded on the left and on the right by edges The Strip tool can measure the edge positions width and height of a strip The Strip tool assumes that regions outside the strip referred to as the base regions Region A and D below deviate in height from the start and end part
6. model fit takes into account the Surface Width Surface Offset Edge Angle and the Edge Type parameters Feature Point Fitted Circle Adjusted Surface Ares Edge Region Edge Region Adjusted Surface Area Parameters Parameter Description Illustration Gap Width Max The maximum width of the gap Allows the tool to fil ter gaps longer than the expected width This could be used to single out the correct gap when there e are multiple gaps in the field of view e Fitted Surface Line Data Void Width Gocator Measurement Tool Technical Manual 9 Parameter Reference Side Measurement AXIS Gap tool only Decision Region Output Description Illustration Defines the side on which the gap is calculated Surface Axis Edge Axis Defines the direction that the gap is calculated Surface In the direction of the fitted surface line of the reference surface Edge In the direction perpendicular to the edge of the reference surface Distance The Cartesian distance between the two Distance Axis feature locations See Decisions page 30 See Regions page 31 See Output Filters page 31 Left Right Side Parameters Parameter Void Width Max Description Illustration The maximum width of the missing data caused by occlusion or data dropout A larger value prevents the algorithm from registering a section of missing e data as an edge Fitted
7. on a set of parameters You can control the measurement regions for the left and the right side A measurement region defines the region in which the measurement tool will search for the feature points Feature points are located on each side using the following algorithm 1 Onthe left side search from left to right to find a surface area with data that covers at least the Surface Width On the right side search from right to left Search Direction 2 If asurface region is found fit a line called the surface line using the data within the area Search Direction Initial Surface Region acg inin a Surf Ca m i eon Fitted Surface Lines 3 Search for avalid edge region that is located at least Surface Offset away from end of the surface region If a surface region is not found move along the search direction and repeat step 1 Gocator Measurement Tool Technical Manual 8 Initial Surface Region search for edge Search for edge Inis iem a Surface p MN j Eger Fitted Surface Lines A valid edge region is detected when an edge matches the Nominal Radius or when the depth exceeds the Minimum Depth The search algorithm uses the Void Width Max to distinguish between an actual edge from an area of missing data referred to as void 4 favalid edge region is detected a model fit is applied to the surface and edge regions to accurately determine the region positions and feature point locations The
8. Description Illustration A point on the best fit circle to be used to calculate the feature point The selected point is on the circumference at the specified angle from the start of the edge region Fitted Surface Line The angle is measured from the axis perpendicular to the fitted surface line Fitted Surface Line Defines the type of feature point and it can be IN either a corner or a tangent A tangent edge point is the point selected based on the defined Edge Angle A corner edge point is the intersect point between the fitted surface line and a edge line formed by interpolating the points at and after the tangent within the edge region Fitted Circle aature Point Groove Algorithm The groove measurement tool first locates valley along the profile line The bottom point of a valley the valley point is the first estimation of the position of the groove bottom For each valley the algorithm searches for corner to the left and to the right to find the groove corners A groove candidate is found when the groove corners are located on the left and right before the next valley is reached Two groove Gocator Measurement Tool Technical Manual 12 candidates may share the same corner as shown in the right image below See the tables below for the parameters used by the algorithm 2 Shared peak 2 Find the peaks to left and right of valley points groove corners ooo d N s eee ecce te e e a
9. e e eoe e Bottom Corner e e E e Left C eee S eft Corner 9 s e e e e e e e e Ce e e JE e e Right Corner e e 9099909906 e Rising Edge e epccccce Examples Point Type Falling Edge pee Finds a falling edge in the region of interest 0 Falling Edge E Any Edge M0 Finds a rising or falling edge in the region of interest C tege e 40900000990 Pobre M Q E Edge e escccccc Median e 2 Determines the median location of points in the region of e Oe Median interest M e Fit Lines Some measurements involve estimating lines in order to measure angles or intersection points A fit line can be calculated using data from either one or two fit areas LINE LINE AREA A AREA A AREA B A line can be defined using one or two areas Two areas can be used to bypass discontinuity in a line segment Gocator Measurement Tool Technical Manual Gap and Flush Algorithm The gap and flush tools use the same algorithm to find a feature This algorithm first searches for two regions on each side a surface region and an edge region See the tables below for the parameters used by the algorithm Left Side Right Side Surface Region Surface Region Edge Region Edge Region After the algorithm finds the regions it places a feature point in the surface region based
10. efinitions in the A gorithm Technical User Manual on how this parameter is used for different base types Specifies the width of the region around the edges from which the data is used to calculate the step change See Strip Step Edge Definitions in the A gorithm Technical User Manual on how this parameter is used by different base types Specifies the nominal width needed to make the transition from the base to the strip See Strip Step Edge Definitions in the A gorithm Technical User Manual on how this parameter is used by different base types The maximum width of missing data allowed for the data to be considered as part of a strip when Void is selected in the Left or Right Edge parameter This value must be smaller than the Edge Support Width Gocator Measurement Tool Technical Manual 18 Parameter Description Gap gt Maximum void Measurement region When occlusion and exposure causes data drops users should use the gap filling function to fill the gaps Minimum Strip Width Specifies the minimum width for a strip to be considered valid Tilt Enables disables tile correction Decision See Decisions page 30 Region The measurement region defines the region in which to search for the strip If possible the region should be made large enough to cover the base on the left and right sides of the strip Sides of the Strip See Regions page 31 for more information Output See Output Filters page 31 Stri
11. ference e 9 The set of refined edges is then used to locate and inspect o e the feature If the Reference Regions option is enabled and set to AutoSet the edges are also used to calculate the location of the reference regions Filter phase The detected location and dimensions are then compared to the nominal and tolerance settings If the refined feature falls within the measurement region and its measurements fit within the specified tolerance the results are reported If not an invalid result is returned Parameters Parameter Description Nominal Radius Expected radius of the hole Radius Tolerance The maximum variation from the nominal radius from the nominal radius Reference Regions The algorithm uses the Reference Regions option to calculate the Z position of the hole It is typically used in cases where the surface around the hole is not flat Gocator Measurement Tool Technical Manual 23 Parameter Description Same Z level Reference Regic Detected Hole Same Z level When this option is set to Autoset the algorithm automatically determines the reference region When the option is not set to Autoset the user manually specifies the reference region The location of the reference region is relative to the detected center of the hole and positioned on the nominal surface plane When the Reference Regions option is disabled the tool measures the hole s Z position using all the data in the
12. i e blocked by reflections Gocator Measurement Tool Technical Manual 13 Fitted lines Fi ve ki ee ee Hees e s ley Poin ga Valley Point o Groove bottom For U shaped and open groove the distance from each point within the groove including the added point for open shaped groove is projected onto the width line The groove bottom s X is at the centroid of the projected values along the width The groove bottom s Z is at the maximum depth of the groove Fitted lines B ral Ne a eo ow Hees DE ley Poin a Valley Point e Groove bottom Groove candidates that do not meet the minimum and maximum width and depth settings are rejected The width and depth measurements are invariant to the groove rotation The width is the distance between the groove corners and the depth is perpendicular distance of the groove bottom from the groove width Parameters Parameter Description Shape Shape of the groove Gocator Measurement Tool Technical Manual 14 Parameter Location Groove X and Groove Z measurements only Select Type Index Minimum Depth Minimum Width Maximum Width Decision Description U Shape V Shape Open Shape Specifies the location type to return Bottom Groove bottom For a U shape and open shape groove the X position is at the the centroid of the groove For a V shape groove the X position is at the intersection of lines fitted to the left
13. lack regions With one or more reference region the algorithm calculates the Z positions as the average values of the data within the regions When the user places the reference region manually all of the data is used whether the data is inside or outside the opening The user should place the reference region carefully Tilt Correction Tilt of the target with respect to the alignment plane Set to Auto Set to have the tool automatically detect the target s tilt or enter the angles manually Auto Set requires the measurement region to cover more areas on the surface plane than other planes The results from the Plane X and Y tool can be used for angles X and Y parameters Decision See Decisions page 30 Region See Regions page 31 Output See Output Filters page 31 Stud Algorithm The Stud algorithm measures the stud in three steps searching for the tip finding the reference plane and shaft fitting See the tables below for the parameters used by the algorithm Searching for the tip The algorithm looks for the approximate location of the tip If Auto Tilt is enabled the algorithm uses the flat surface around the tip to estimate the orientations of the part The approximate tip is the location of the highest maximum Z pixel after correction for the nominal tilt angle Finding the reference plane The reference regions are positioned using the approximate tip the nominal angle values and the nominal stud length Com
14. measurement region except for a bounding rectangular region around the hole Tilt Correction Tilt of the target with respect to the alignment plane When this option is set to Autoset the tool automatically detects the tilt Otherwise the user must enter the angles manually Autoset requires the measurement region to cover more areas on the surface plane than other planes The results from the Plane X and Y tool can be used for angles X and Y parameters Partial Detection Enable if only part of the hole is within the measurement region If disabled the hole must be completely in the region of interest for results to be valid Gocator Measurement Tool Technical Manual 24 Parameter Description Decision See Decisions page 30 Region See Regions page 31 Output See Output Filters page 31 Opening Algorithm The Opening tool processes the data in three phases Search Measure and Filter See the tables below for the parameters used by the algorithm Search phase The tool searches for coarse data transitions edge data and performs a coarse fitting of the opening shape specified by the orientation angles and the nominal dimensions to determine the most likely candidate If Tilt Correction is enabled the algorithm uses the flat surface in the measurement region to estimate the orientation of the part Measure phase A more rigorous edge detection NE algorithm is applied to precisely determine the iu tee edges arou
15. nd the feature Edge detection at this LM NM stage will reject outliers and noise The algorithm ware T Serum requires opposite sides and ends to be associated with a comparable number of edge pixels with the weaker side or end having at least 2596 of the stronger The set of refined edges is then used to locate and inspect the feature If the Reference Regions setting is enabled the edges are also used to calculate the location of the reference regions Gocator Measurement Tool Technical Manual 25 Filter phase The detected location and dimensions are compared to the nominal and tolerance settings If the refined feature falls within the measurement region and its measurements fit within the specified tolerance the results are reported If not an invalid result is returned Parameters Parameter Type Nominal Width Nominal length Nominal Angle Nominal Radius Description Rounded Slot Rectangle Nominal width of the opening Nominal length of the opening Nominal angle of the opening The default orientation is the length of the opening along the X axis Orientation 0 degrees Orientation 90 degrees Y Y A A X gt X Pp The diagram above illustrates the case where the surface is not tilted When the surface is tilted the orientation is defined with respect to the normal of the surface not with respect to the X Y plane Nominal radius of the opening ends If the opening t
16. nt Tool Technical Manual 30 Output Filters Output filters can be applied to measurement values before they are output from the Gocator sensors Operation Description Scale and Offset The Scale and Offset settings are applied to the measurement value according to the following formula Scale Value Offset Scale and Offset can be used to transform the output without the need to write a script For example to convert the measurement value from millimeters to thousands of an inch set Scale to 39 37 Hold Last Valid Hold the last valid value when the measurement is invalid Measurement is invalid if there is no valid value Smoothing Apply moving window averaging to reduce random noise in a measurement output The averaging window is configured in number of frames If Hold Last Valid is enabled smoothing uses the output of the Hold Last Valid filter Output Scde 1 Offset 0 E Hold last walid E Smoothing 1 Samples To configure the output filters 1 Select a measurement Click on the in a measurement panel to expand it Click the arrow next to Output to expand the panel 2 Enable filters and configure the settings Regions The Region parameter is used to limit the region in which a measurement will occur See the individual tools for details on the best way to use this parameter with each tool The parameter can be configured graphically using the mouse in the data viewer when the Measuremen
17. p Start and Terminate Conditions The Strip tool allows you to define how a strip starts and ends The Left Edge parameter controls how a strip starts and the Right Edge parameter controls how a strip ends Start terminate conditions Condition Description Rising Rising step edge detected based on the strip edge parameters See Strip Step Edge Definitions page 21 for details on how the step edge is detected Falling Falling step edge detected based on the strip edge parameters See Strip Step Edge Gocator Measurement Tool Technical Manual 19 Condition Description Definitions page 21 for details on how the step edge is measured Data end The first for the left edge or the last for the right edge valid profile data point in the measurement region Left edge data end Right edge data end Measurement region Void Gaps in the data that are larger than the maximum void threshold Gap gt Maximum void Measurement region Gaps at the ends of the measurement region s boundary are not considered as a void Measurement region Data end These gaps are not void The following examples show how the parameters affect the strip detection in different scenarios Leftand Right Edge conditions Condition Example Left Rising data end void Strip 0 Strip 1 Right Falling data end void D Gocator Measurement Tool Technical Manual 20 Condition Example Left Rising void Right Falling void Lef
18. pared to the hole opening misplaced stud reference regions are more likely to cause a failure to produce any measurement Gocator Measurement Tool Technical Manual 20 Shaft fitting The shaft region is determined based on the approximate tip position the nominal angles the reference plane position and the stud nominal size parameters Shaft fitting is successful if the algorithm can fit at least three circles with the stud diameter along the shaft Fitting each circle requires sufficient data along the top portion the shaft Because of occlusions the bottom of the shaft is often not visible to the sensor and the algorithm is designed to handle this situation Parameters Parameter Nominal Stud Radius Nominal Stud Length Base Height Tip Height Radius Offset Reference Regions Tilt Correction Decision Region Output Gocator Measurement Tool Technical Manual Description Expected radius of the stud Expected length of the stud The height above the base surface that will be ignored when the truncated cone is fit to the stud data The height from the top of the surface that will be ignored when the truncated cone is fit to the stud data The distance from the tip of the stud from which the radius is measured The algorithm uses reference regions to calculate the base plane of the stud Reference regions are relative to the base of the stud Tilt of the target with respect to the alignment plane Se
19. point in the measurement region Void Gap in the data that is larger than the maximum void threshold Gaps connected to the measurement region s boundary are not considered as a void See Strip Start and Terminate Conditions in the A gorithm Technical User Manual for the definitions of these conditions Gocator Measurement Tool Technical Manual 17 Parameter Right Edge Select Type Index Minimum Edge Height Edge Support Width Edge Transition Width Maximum Void Description Specifies the features that will be considered as the strip s right edge You can select more than one condition Rising Rising edge detected based on the strip edge parameters Falling Falling edge detected based on the strip edge parameters Data end Last valid profile data point in the measurement region Void Gap in the data that is larger than the maximum Void parameter Gaps connected to the measurement region s boundary are not considered as a void See Strip Start and Terminate Conditions in the A gorithm Technical User Manual for the definitions of these conditions Specifies how a strip is selected when there are multiple strips within the measurement area Best The widest strip Index from The Left 0 based strip index counting from left to right Index from the Right O based strip index counting from right to left O based strip index Specifies the minimum deviation from the strip base See Strip Step Edge D
20. point with the maximum Z value in the region of JOH n e e interest Ese e 9 a Bottom Finds the point with the minimum Z value in the region of e e interest t oe s XO Bottom Left Finds the point with the minimum X value in the region of interest ee Right Finds the point with the maximum X value in the region of interest ud s o 9 Right e Average Determines the average location of points in the region of Ce ete O Average interest e Gocator Measurement Tool Technical Manual Point Type Corner Finds a dominant corner in the region of interest where corner is defined as a change in profile slope Top Corner Finds the top most corner in the region of interest where corner is defined as a change in profile shape Bottom Corner Finds the bottom most corner in the region of interest where corner is defined as a change in profile shape Left Corner Finds the left most corner in the region of interest where corner is defined as a change in profile shape Right Corner Finds the right most corner in the region of interest where corner is defined as a change in profile shape Rising Edge Finds a rising edge in the region of interest Gocator Measurement Tool Technical Manual Examples Corner Os E i Top Corner e e e ecco ec 99
21. s of a strip Region B and C See the tables below for the parameters used by the algorithm B C 0o E 9 9 e e e o o Cee 6 A D Base Base When the target is sitting on the surface the base is lower than the strip as shown above Alternatively for a groove the base is above the strip surface The base could be missing when the target is hanging in the air or the surface holding the target falls outside the sensor s active area You can control the base type in the measurement panel The Strip tool can detect multiple strips You can select an ROI referred to as the measurement region from which the algorithm search for multiple strips Gocator Measurement Tool Technical Manual 16 Parameters Parameter Base Type Location Strip Height Strip X and Strip Z measurements only Left Edge Measurement Region Pa ain MN Description Specifies if the strip has a base or not Base Type Flat Base Type None Specifies the strip position from which the measurements are performed Left Left edge of the strip Right Right edge of the strip Center Center of the strip Specifies the features that will be considered as the strip s left edge You can select more than one condition Rising Rising edge detected based on the strip edge parameters Falling Falling edge detected based on the strip edge parameters Data end First valid profile data
22. t Rising Right Data end void Left Data end void Strip 0 Right Falling Left Falling Right Rising The Strip tool detects step edges based on the parameters Base Type Edge Transition Width Edge Support Width and Minimum Edge Height When Base Type is set to Flat the regions around the edges are visible and the edge positions are between the base and the strip surface Edge Support Width Edge Position Edge Height Edge Transition Width The Minimum Edge Height parameter defines the size of the step edge The Edge Transition Width parameter specifies the nominal width of the transition from the base to the strip surface Gocator Measurement Tool Technical Manual 21 The Edge Support Width parameter defines the width of the region around the edges from which the data is used to measure the step change This region should be relatively smooth and flat To improve noise immunity the height level of the Edge Support Width parameter is calculated by averaging the data within the region When the base is set to None the tool looks for continuous sections that are wider than the Edge Support Width parameter and have no data points that deviate positively or negatively more than the value of the Minimum Edge Height parameter The height level of the continuous region is calculated based on the fitted line as shown below First data point deviates more than Edge Height The algori
23. t page is active Some measurements use more than one region Gocator Measurement Tool Technical Manual 31 Parameters Region R X 28 704 mm Width 71475 mm Y 41 803 mm Length 71 593 mm 7 50 mm Height 100 mm Output Decision Min 0 mms Max 0 mm3 Remove This parameter is also referred to as a measurement region To configure regions 1 Select a measurement Click on the in a measurement panel to expand it 2 Check the Region checkbox to enable a region 3 Configure the region using the fields You can also configure the region graphically using the mouse in the data viewer Gocator Measurement Tool Technical Manual 32
24. t to Auto Set to have the tool automatically detect the tilt or enter the angles manually Auto Set requires the measurement region to cover more areas on the surface plane than other planes The results from the Plane X and Y tool can be used for angles X and Y parameters See Decisions page 30 See Regions page 31 See Output Filters page 31 29 Common Parameters Decisions Results from a measurement tool can be compared against minimum and maximum thresholds to generate pass fail decisions The decision state is pass if a measurement value is between the minimum and maximum threshold in the user interface these values are displayed in green Otherwise the decision state is fail in the user interface these values are displayed in red 9 Area 4 2978 250 Link Disabled vw D4 Parameters Region R gt Output Decision Min 2978 mm2 Max 2979 mm2 Remove Value 50 380 is within the decision thresholds Min 80 Max 100 Decision Pass 9 Area 4 2978 250 Link Disabled ID 4 Parameters Region R gt Output Decision Min 2979 mm2 Max 2980 mm2 Remove Value 102 928 is outside the decision thresholds Min 80 Max 100 Decision Fail Along with measurement values decisions can be sent to external programs and devices In particular decisions are often used with digital outputs to trigger an external event in response to a measurement Gocator Measureme
25. thm then backs off by the value of the Edge Transition Width parameter and uses the data up to the back off point to create the fitted line and projects the edge point on the line This step prevents the points near the end of a rounded strip from affecting the height of the strip Gocator Measurement Tool Technical Manual 22 Part Tools Hole Algorithm The Hole tool processes the data in three phases Search Measure and Filter The algorithm can separate out background information that appears inside the hole It can also detect holes that only partially appear in the data See the tables below for the parameters used by the algorithm Search phase The tool searches for coarse data transitions edge data and performs a coarse fitting of the hole model specified by the orientation angles and the nominal value to determine the most likely candidate If Tilt Correction is set to Autoset the algorithm uses the data within the measurement region to estimate the orientation of the part Measure phase A more rigorous edge detection At least 2596 of the points around the algorithm is applied to precisely determine the edges circle should be present around the feature Edge detection at this stage will reject x outliers and noise The algorithm requires at least 25 of e 9 the data around the hole for the candidate to remain 1 valid The accuracy of the algorithm improves when the points e are spread more evenly along the hole s circum
26. ype is set to rectangular the radius setting is disabled The opening has an oval shape if the radius is equal to of the width The opening is a rounded rectangle when the radius is less than of the width Gocator Measurement Tool Technical Manual 26 Parameter Description Radius 1 2 width Radius width Radius gt width Radius vA Width Width Length a me Length E f N Width m gt Length Width Tolerance The maximum variation from the nominal width from the nominal value Length Tolerance The maximum variation from the nominal length from the nominal value Orientation Tolerance The maximum variation from the nominal orientation from the nominal value Reference Regions The algorithm uses reference regions to calculate the Z position of the hole Reference regions are relative to the center location of the feature This option is typically used in cases where the surface around the opening is not flat Same Z level Reference Region Detected Opening Same Z level When the Reference Regions setting is disabled the tool measures the hole s Z position using the all data in the measurement region except for a bounding rectangular region around the opening Gocator Measurement Tool Technical Manual 27 Parameter Description Data used to calculate Z position orange Opening Data NOT used for Z calculation blue or b
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