Research Article LabVIEW 2010 Computer Vision Platform

Hindawi Publishing CorporationJournal of Analytical Methods in ChemistryVolume 2013 Article ID 193230 8 pageshttpdxdoiorg1011552013193230

Research ArticleLabVIEW 2010 Computer Vision Platform Based VirtualInstrument and Its Application for Pitting Corrosion Study

Rogelio Ramos Roumen Zlatev Benjamin Valdez Margarita Stoytcheva Moacutenica Carrilloand Juan-Francisco Garciacutea

Engineering Institute Autonomous University of Baja California Boulevard Benito Juarez SN 21280 Mexicali BCN Mexico

Correspondence should be addressed to Roumen Zlatev roumenuabcedumx

Received 9 November 2012 Revised 30 January 2013 Accepted 17 February 2013

Academic Editor Maria da Conceicao Branco Montenegro

Copyright copy 2013 Rogelio Ramos et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A virtual instrumentation (VI) system called VI localized corrosion image analyzer (LCIA) based on LabVIEW 2010 was developedallowing rapid automatic and subjective error-free determination of the pits number on large sized corroded specimens The VILCIA controls synchronously the digital microscope image taking and its analysis finally resulting in a map file containing thecoordinates of the detected probable pits containing zones on the investigated specimenThe pits area traverse length and densityare also determined by the VI using binary large objects (blobs) analysis The resulting map file can be used further by a scanningvibrating electrode technique (SVET) system for rapid (one pass) ldquotruefalserdquo SVET check of the probable zones only passingthrough the pitrsquos centers avoiding thus the entire specimen scan A complete SVET scan over the already proved ldquotruerdquo zones coulddetermine the corrosion rate in any of the zones

1 Introduction

The increased application of self-constructed LabVIEW-based chemical virtual instruments (VIs) is due to their flexi-bility and ability to satisfy all the specific user requirementscombined with the simplicity of the construction Manyconfigurations of LabVIEW-based VI have been reporteduntil now corresponding to their specific chemical applica-tion defined by the user needs Meng et al [1] described aVI system based on LabVIEW 80 for ion analyzer whichcan measure and analyze ion concentrations in solutioncomprising a high input impedance voltmeter (widely usedin measuring the EM generated by ion selective electrode)a homemade conditioning circuit data acquisition boardand a computer It can calibrate automatically the slopetemperature and positioning When applied to determinethe reaction rate constant by pX it achieved live acquir-ing real-time displaying automatic processing of testingdata generating a report of results and other functionsThis method simplifies the experimental operation avoidscomplicated procedures of manual data processing and per-sonal error and improves veracity and repeatability of the

experiment results Wang et al [2] reported a LabVIEW-based chemical virtual instrument (VI) for temperaturesand pressures measurement By selecting hardware modulessuch as the PCI-DAQ card or serial port method and thesoftware modules different kinds of sensors can be used forcreating different chemical instruments allowing extremelyflexible solutions for automatic measurements in the physicalchemistry research Lenehan et al [3] developed a LabVIEW-based software for the automation of a sequential injectionanalysis instrument for the determination of morphineThe detection is based on chemiluminescence reaction withacidic potassium permanganate in the presence of sodiumpolyphosphate The authors reported excellent analyticalcharacteristics of the developed LabVIEW-based softwaresystem to be achieved the precision of the determinationwas 07measured by the relative standard deviation for fivereplicate measurements of morphine standard and the limitof detection was determined to be as low as 5sdot10minus11M Bowieet al [4] reported a flow-injection- (FI-) based instrumentunder LabVIEW control for iron monitoring in marinewaters The instrument incorporates a miniature low-powerphotomultiplier tube (PMT) and a number of electric and

2 Journal of Analytical Methods in Chemistry

solenoid actuated microvalves and peristaltic pumps Thesoftware allows full control of all flow injection componentsand the processing of the data from PMT The optimizedsystem is capable of 20 injections per hour including pre-concentration and wash steps The analytical characteristicsof the developed LabVIEW-based system are reported to beas follows a detection limit of 21 pM at linear range of 21ndash2000 pM with a 60-second sample load time and averageprecision between replicate FI peaks of 59 plusmn 32 (119899 = 4)over the linear range

The flexibility of the VIs allows their application practi-cally in any branch of the chemical technology For examplethe quality control of the conversion coating on aluminumalloys requires the determination of the pits number appear-ing on the 3times 10 inches control specimens after their testing insaline chamber at extreme conditions high temperature highrelative humidity and high saline concentration accordingto the standard ASTM B117 According to this standard thenumber of the appearing pits is the measure of the corrosionresistance of the protective coating The pits counting how-ever actually made by simple specimen observation results insubjective errors due to the bad distinction of the pits fromsome ldquopits-likerdquo simple stains andhence false results about thecorrosion resistance of the conversion coatings That is whya rapid and subjective error-free method for pits counting isnecessaryThus the purpose of the present work is to developsuch a VI and to test it on real specimens for express andobjective pits counting

Such a VI must determine the pit centers coordinatespit areas their traverse lengths and the densities using blobsanalysis resulting in a map file which can be used furtherby a SVET system [5ndash7] to perform a rapid (one pass)ldquotruefalserdquo check of the probable pit containing zones onlywithout scanning of the entire specimen A VI fulfilling allthese requirements using a particle analysis based on blobsanalysis [4] included in IMAQ libraries [5] for LabVIEW2010 called localized corrosion image analyzer (LCIA) wasdeveloped and described in the present paper Its hardwareand software are presented together with some application forpit recognition on real metal samples

The specimen optical scan performed by a digitalmicroscope connected to a PC yields a database file (a mapfile) containing the coordinates of all the surface defectssimilar to pits not only the ones caused by corrosionImage analysis performed by LabVIEW 2010 was applied forpreliminary image recognition and distinction of the pitsThe created mapmust be actualized by ldquotruefalserdquo SVET testapplication allowing the distinction of the true corroded (pitcontaining) zones from the ldquocorroded-likerdquo ones to be usedfurther froma SVET system for corrosion rate determinationThe truefalse test is a rapid single linear SVET scan over thecenters of the probable zones in which coordinates are savedin the created by the VI LCIA map file The simple linearSVET scanwill result in a specific and easy recognizable peakscontained curve in coordinates current intensitycoordinate

The scanning vibrating electrode technique (SVET)which was developed for biological applications [5] wasadapted later by Isaacs [6 7] for corrosion studies of pitting

intergranular and galvanic corrosion SVET allows the deter-mination of the current distribution above the metal surfacemeasuring the potential gradient (voltage drop) proportionalto the ionic current density Δ119864 = (119868

1

minus 1198682

)119877 that appearsbetween the two levels of the electrode vibration (from 1to 100 120583m) above the studied surface SVET is a furtherdevelopment of the scanning reference electrode technique(SRET) [8 9] but provides higher sensitivity due to ac signalmeasurement allowing obtaining a higher signal to noise(SN) ratio due to the better noise suppression For examplethe minimal voltage drops levels measurable by SRET areabout 200120583V [10 11] while 5 120583V can be achieved by SVET[12ndash14]

The LabVIEW-based VI subject of the present paperemploys the first main point of the approach developed bythe authors based on the following two main points

(i) computer vision application for video inspection bydigital microscope of the surface of interest anddatabase (map file) creation of the probable pitscontaining areas

(ii) rapid ldquotruefalserdquo test by single linear SVET scan forreal pits distinction followed by a map file actualiza-tion

Additionally a complete SVET scanning of the recog-nized real pits areas can be performed if the corrosion ratedetermination is necessary The VI performing the videoinspection and the creation of the map file only is the subjectof the present work while the SVET VI is the subject ofanother publication

2 Systemrsquos Hardware Configuration

Three main devices were involved in the system hardwareconfiguration a video inspection mighty scope near infrared10xndash200x 13MP 141015840 CMOS color 6 LED light type oper-ating at 850 nm USB 20 interfaced digital microscope witha homemade lineal stage focus controlling mechanism inthe range from 85mm to 112mm with stepper motor NPMPF35-24C1 a homemade SVET device with X-Y stagesstepper motors VEXTAmodel PX245M-01A and a personalcomputer Dell Optiplex 7010 Core i7 CPU 340GHzWindows 8 Pro operating system as illustrated in Figure 1

The optical inspection by a digital microscope allows thecapturing of full images from 4mm2 to 1700mm2 (opticalzoom in the range from 10x to 200x) respectively of thestudied surface with a resolution of 1600 to 1200 effectivepixels at shot speed user controllable from 1 to 11000 secThefocus adjustingmechanism (Y stage Figure 1) was driven by astepper motor controlled by the LCIAwhich controls also thereal time image capturing and its transfer through the USBinterface The white balance was carried out automaticallyemploying the integrated 6 white LED light ring around thelenses

The homemade SVET device [15] which uses the map fileproduced by the VI subject of the present work consists ofa vibrating electrode with edge diameter of approximately1 120583m 100mV p-p and frequency of the vibration of 60Hz

Journal of Analytical Methods in Chemistry 3

Stepper motor

Digital microscope

Sample

Focusmotion controller

Personal computer

USB

USB

Preamplifier DASUSB 6009

Motion controller SVET

Sample

USB

USB Vibrating electrode

119884

119884

stage

119883

119883-119884 stages

Figure 1 VI LCIA system configuration

at amplitude of the displacement adjustable in the rangebetween 1 and 100 120583m over the specimen surface The vibrat-ing electrode was mounted on X-Y linear stages mechanismproviding 5 120583mstep resolution The SVET electrode X-Ydisplacement and vibration were controlled by a separate VIinstrument running its own software and communicatingwith the LCIA using the map file containing the pitscoordinates previously obtained with the LCIA The SVETanalog signal was amplified by a controlled gain high inputimpedance instrumentation preamplifier (1013Ohm100 fA)and after its digitalizing by national instruments modelUSB 6009 data acquisition system (DAQ) digital signal wastransferred to the PC through the USB port and processed byits VI lock-in amplifier LabVIEW tool

21 Systemrsquos Operation TheLCIA focuses captures the imageof the specimen surface and analyzes it creating a databasefile in real time containing the exact coordinates area andtransverse length of probable pits This file is employed bya SVET system with its own control software performingthe truefalse test to distinguish the true pits coordinatesIn ldquotruerdquo case a complete SVET scan of the probable areacan be performed and the corrosion rate be determined ifpreliminary chosen by the operator in the interface screen Inldquofalserdquo case the SVET electrode goes to the next probable areaup to the last using optimized trajectory In both cases afterthe truefalse test performance an updating of the alreadyexisting database file takes place

3 Programming

The flow diagram of VI LCIA system shown in Figure 2 isdivided in two main subvirtual instruments image digitizingsub-VI and image analyzing sub-VI both executed to get the

complete pits location information The image digitizing sub-VI creates the samplersquos digital image by making a previewfocusing image capturing histogram display and focusverification entirely synchronized in real time with the imageanalyzing sub-VI Both sub-VIs are implemented in ldquostackedsequence 1rdquo structure where the image digitizing sub-VI isexecuted for frame 0 of stacked sequence 1 and the imageanalysis sub-VI is executed for frame 1 of stacked sequence 1(see Figure 2)

31 Digitizing Sub-VI General Description The image digi-tizing sub-VI is located in frame 0 of the Stacked Sequence 2inside the Stacked Sequence 1 shown in Figure 3 where thefunctions focus and image preview are performed simulta-neouslywithin a ldquowhile loop execution controlrdquoThe focus hastwo nested ldquocaserdquo structures When the main ldquocaserdquo structureis true the focus starts by the execution of ldquofocus sectionrdquosub-VI through a ldquocase true substructurerdquo this process callsup the node for writing via USB to control the driver ofstepper motor mounted on the focus mechanism it focusesby using a ldquoforrdquo cycle and a structure type stacked sequence(programming shown on Figure 3) When the main casestructure is false however it calls up through the USB portthe writing node which indicates the motor driver to de-energize the motor and by this way the focusing processstops The previously mentioned procedure sets the forwardor backward sequence to control the execution time thespeed of the focus mechanism stepper motor and the focustermination through the control driver

32 Digitizing Sub-VI Image Preview and Real-Time FocusingThe image preview is made by using the LabVIEW NiIMAQdx libraries tools that allow the reading of camera ormicroscope through aUSB portThis job is performedwithin


VI system

ADIPCL

StopYes

Yes Yes

Imagedigitalization Image analysis

Capture set parameters Analysis set parameters

Focus Umbral adjust

Save and stop

file ready to SVET Capture

NoNo

Figure 2 Flow diagram for VI LCIA

an ldquoeventrdquo structure (see Figure 3) and allows simultaneousreal-time image observation and focusing

The image preview is taken by the application of theLabVIEWNi IMAQdx tool [16] allowing automatic detectionand camera(s) selection by the user via the USB port Thissub-VI is implemented outside the ldquowhile looprdquo and insidethe ldquoeventrdquo structure shown in Figure 3

33 Digitizing Sub-VI Image Capture Focus Verification andImage Save Once the ldquocapturerdquo button located on the sub-VI front panel is pressed the frame 0 of stack sequence 2terminates and the frame 2 starts automatically capturing theimage and saving it in lowastjpg format file (the programming isshown in Figure 4) After saving the generated file the sub-VI ldquocontentrdquo generates the corresponding histogram for theimage capturing Figure 5 shows the user graphic interface(the front panel of VI LCIA for the image digitizing) wherethe corroded surface image already captured is displayedtogether with the corresponding histogram According tothe histogram values the user decides to keep the image forfurther analysis or to delete it and run the process again

34 Image Analysis Sub-VI In the image analysis applied byVI LCIA to metal samples for pitting corrosion determina-tion described on this document the blob analysis of IMAQ

library from LabVIEW 2010 [17] was applied This techniqueinvolves several vision operations and analytical procedureswhich detect within the image any 2D object which could bea potential pit located on the studied corroded metal surfaceThe image processing generates blobs and then works withthem to calculate the area and perimeter of the pit and thenumber of the generated blobs is an important characteristicfor pits distinguishing Blob (binary large object) is a group ofinterconnected pixels that have the same logic state and thesame light intensity [18]

The basic structure of an image recognition VI by theapplication of blob analysis in IMAQ LabVIEW consists ofimage acquisition histogram calculation thresholding andblobrsquos filtering and analysis

The image recognition VI for pitting corrosion applica-tion has all these components as well as the morphology andparticle labeling to improve the shape and definition of pitsunder investigationThe programming diagram of the imageanalysis sub-VI is shown in Figure 6

By means of the icons IMAQ create and IMAQ readfile the precaptured images are acquired into the sub-VI fordigitizingAfter that the color threshold process is performedto turn the image into binary format in the first sectionOnce the threshold process is done the desired morphologyof pitting is predefined by IMAQ morphology and then afiltering process is performed by IMAQ particle filter whichcan be used to clean up the image deleting the nondesiredparticles defined as noise The pitting spots in the alreadyclean image are labeled and highlighted in different colorsby IMAQ label so they can be easily distinguished Finallythe pitting spots which are pixels are counted to be convertedin real metric units by IMAQ particle analysis and savedtogether with the LCIA generated parameters as pit locationarea and transverse length

Once the blob analysis is performed the system proceedsto convert pixels to metric units for all the parametersdetermined by the blob analysis (program process shown inFigure 5) The conversion to square millimeters of the areais performed by the subarray from array subset area theconversion to millimeters of the length is performed by thesubarray from array subset length and finally the location bycoordinates in the subarrays (X Y) performed by array subsetfor coordinate X and coordinate Y respectively

4 Applications

The system VI LCIA was applied for image recognitionin localized corrosion studies of aluminum alloys AA6061-T3 specimens determining the number density and coor-dinates of probable pits areas together with their dimen-sions Then the created database file was employed forreal-time scanning of the affected by the corrosion areasonly employing SVET improving thus the scanning timemore than ten times compared with the time for completeSVET scan of the entire surface In Figure 7(a) left isshown the microscope image of a carbon steel UNS G10180sample obtained with VI LCIA application There one ofthe pits is highlighted with a circle as an example and


Figure 3 Digitizing sub-VI image preview and focusing

Figure 4 Sub-VI for image caption

in the right part of the same figure its identification byVI LCIA is shown determining its area to be 0041mm2and its transversal length to be 176 times 094mm as dis-played in the graphic interface of the image analysis sub-VI These values fit very well with those obtained by theSVET device and the AMF microscope application Thetotal time for the SVET scan of the 25 times 25mm specimenwith the LCIA application was found to be about 4

only of the total time required for complete SVET scan ofthe same specimen achieving an acceleration of about 25times [14]

5 Conclusions

A virtual instrumentation system called VI LCIA based onLabVIEW 2010 was developed allowing rapid determination


Figure 5 Imagersquos caption front panel

Figure 6 Blobs analysis and pixel conversion to metric units

of the pits number on large metal specimens The VI LCIAcontrols synchronously the focus adjustment and the imagetaking by a digital microscope and the image analysisresulting in detection and the mapping of the probable

pits containing zones on the corroded metal specimen withtheir traverse length and density using blobs analysis Thecreated map is further used by a homemade SVET VIsystem with its own LabVIEW 2010 software to control


(a)

(b)

Figure 7 (a) Left specimen microscope image (a) right map of the probable pits areas created by LCIA using the microscope image (b) theLCIA user interface

a rapid performing (one pass scan) ldquotruefalserdquo check of theprobable pits containing zones and also is able to perform acomplete SVET scan of the already recognized ldquotruerdquo zonesto determine the corrosion rate

Acknowledgments

The authors are pleased to acknowledge the Materials andCorrosion Laboratory and the Automatization and VirtualInstrumentation Laboratory of the Engineering Institute ofthe Autonomous University of Baja California Mexico forthe support in the development and experimentation relatedto the present work

References

[1] H Meng J-Y Li and Y-H Tang ldquoVirtual instrument fordetermining rate constant of second-order reaction by pXbased on labVIEW 80rdquo Journal of Automated Methods andManagement in Chemistry vol 2009 Article ID 849704 7pages 2009

[2] W Wang J Li and Q Wu ldquoThe design of a chemical virtualinstrument based on LabVIEW for determining temperaturesand pressuresrdquo Journal of AutomatedMethods andManagementin Chemistry vol 2007 Article ID 68143 7 pages 2007

[3] C E Lenehan N W Barnett and S W Lewis ldquoDesign ofLabVIEW-based software for the control of sequential injectionanalysis instrumentation for the determination of morphinerdquoJournal of Automated Methods and Management in Chemistryvol 24 no 4 pp 99ndash103 2002

[4] A R Bowie E P Achterberg S Ussher and P J WorsfoldldquoDesign of an automated flow injection-chemiluminescenceinstrument incorporating a miniature photomultiplier tubefor monitoring picomolar concentrations of iron in seawaterrdquoJournal of Automated Methods and Management in Chemistryvol 2005 no 2 pp 37ndash43 2005

[5] L Jaffe and R Nucitelli ldquoAn ultrasensitive vibrating probe formeasuring steady extracellular currentsrdquo Journal of Cell Biologyvol 63 no 2 pp 614ndash628 1974

[6] H S Isaacs ldquoEffect of height on the current distribution meas-ured with a vibrating electrode proberdquo Journal of the Electro-chemical Society vol 138 no 3 pp 722ndash728 1991

[7] H Isaacs Localized Corrosion R Staehle B Brown J Krugerand A Agarwal Eds NACE Houston Tex USA p 158 1974


[8] S Fujimoto and T Shibata ldquoMeasurement and evaluation ofcorrosion and corrosion protection (3) Characterization oflocalized corrosion scanning vibrating electrode techniquerdquoDenki Kagaku vol 64 no 9 pp 967ndash971 1996

[9] H S Isaacs and Y Ishikawa ldquoCurrent and potential transientsduring localized corrosion of stainless steelrdquo Journal of theElectrochemical Society vol 132 no 6 pp 1288ndash1293 1985

[10] K R Trethewey D A Sargeant D J Marsh and A A TamimildquoApplications of the scanning reference electrode technique tolocalized corrosionrdquo Corrosion Science vol 35 no 1-4 pp 127ndash129 1993

[11] E Gileadi E Kirowa-Eisner and J Penciner Interfacial Electro-chemistry p 216 Addison-Weseley Reading Mass USA 1975

[12] R S Thornhill and U R Evans ldquo109 The electrochemistry ofthe rusting process along a scratch-line on ironrdquo Journal of theChemical Society pp 614ndash621 1938

[13] R S Thornhill and U R Evans ldquo402 The electrochemistry ofthe corrosion of partly immersed zincrdquo Journal of the ChemicalSociety pp 2109ndash2114 1938

[14] R Ramos R K Zlatev M S Stoytcheva B Valdez and SKiyota ldquoNovel SVET approach and its application for rapidpitting corrosion studies of chromatized aerospatiale aluminumalloyrdquo Novel SVET ECS Transactions vol 29 no 1 pp 23ndash312010

[15] R Ramos R K Zlatev M S Stoytcheva B Valdez S FloresandAMHerrera ldquoPitting corrosion characterization by SVETapplying a synchronized noise suppression techniquerdquo ECSTransactions vol 29 no 1 pp 33ndash42 2010

[16] NI-IMAQdx User Manual September 2006 Part Number371970A-01 National Instruments Corporation httpwwwnicompdfmanuals371970apdf

[17] Counting Particles or Cells Using IMAQ Vision NationalInstruments Corporation httpwwwnicomwhite-paper3169en

[18] Analisis y procesamiento de imagenes National InstrumentsAlliance Member httpwwwtracnovacomtracnova-pubAnE1lisis20amp20ProcImE1genespdf

Submit your manuscripts athttpwwwhindawicom

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Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


solenoid actuated microvalves and peristaltic pumps Thesoftware allows full control of all flow injection componentsand the processing of the data from PMT The optimizedsystem is capable of 20 injections per hour including pre-concentration and wash steps The analytical characteristicsof the developed LabVIEW-based system are reported to beas follows a detection limit of 21 pM at linear range of 21ndash2000 pM with a 60-second sample load time and averageprecision between replicate FI peaks of 59 plusmn 32 (119899 = 4)over the linear range

The flexibility of the VIs allows their application practi-cally in any branch of the chemical technology For examplethe quality control of the conversion coating on aluminumalloys requires the determination of the pits number appear-ing on the 3times 10 inches control specimens after their testing insaline chamber at extreme conditions high temperature highrelative humidity and high saline concentration accordingto the standard ASTM B117 According to this standard thenumber of the appearing pits is the measure of the corrosionresistance of the protective coating The pits counting how-ever actually made by simple specimen observation results insubjective errors due to the bad distinction of the pits fromsome ldquopits-likerdquo simple stains andhence false results about thecorrosion resistance of the conversion coatings That is whya rapid and subjective error-free method for pits counting isnecessaryThus the purpose of the present work is to developsuch a VI and to test it on real specimens for express andobjective pits counting

Such a VI must determine the pit centers coordinatespit areas their traverse lengths and the densities using blobsanalysis resulting in a map file which can be used furtherby a SVET system [5ndash7] to perform a rapid (one pass)ldquotruefalserdquo check of the probable pit containing zones onlywithout scanning of the entire specimen A VI fulfilling allthese requirements using a particle analysis based on blobsanalysis [4] included in IMAQ libraries [5] for LabVIEW2010 called localized corrosion image analyzer (LCIA) wasdeveloped and described in the present paper Its hardwareand software are presented together with some application forpit recognition on real metal samples

The specimen optical scan performed by a digitalmicroscope connected to a PC yields a database file (a mapfile) containing the coordinates of all the surface defectssimilar to pits not only the ones caused by corrosionImage analysis performed by LabVIEW 2010 was applied forpreliminary image recognition and distinction of the pitsThe created mapmust be actualized by ldquotruefalserdquo SVET testapplication allowing the distinction of the true corroded (pitcontaining) zones from the ldquocorroded-likerdquo ones to be usedfurther froma SVET system for corrosion rate determinationThe truefalse test is a rapid single linear SVET scan over thecenters of the probable zones in which coordinates are savedin the created by the VI LCIA map file The simple linearSVET scanwill result in a specific and easy recognizable peakscontained curve in coordinates current intensitycoordinate

The scanning vibrating electrode technique (SVET)which was developed for biological applications [5] wasadapted later by Isaacs [6 7] for corrosion studies of pitting

intergranular and galvanic corrosion SVET allows the deter-mination of the current distribution above the metal surfacemeasuring the potential gradient (voltage drop) proportionalto the ionic current density Δ119864 = (119868

1

minus 1198682

)119877 that appearsbetween the two levels of the electrode vibration (from 1to 100 120583m) above the studied surface SVET is a furtherdevelopment of the scanning reference electrode technique(SRET) [8 9] but provides higher sensitivity due to ac signalmeasurement allowing obtaining a higher signal to noise(SN) ratio due to the better noise suppression For examplethe minimal voltage drops levels measurable by SRET areabout 200120583V [10 11] while 5 120583V can be achieved by SVET[12ndash14]

The LabVIEW-based VI subject of the present paperemploys the first main point of the approach developed bythe authors based on the following two main points

(i) computer vision application for video inspection bydigital microscope of the surface of interest anddatabase (map file) creation of the probable pitscontaining areas

(ii) rapid ldquotruefalserdquo test by single linear SVET scan forreal pits distinction followed by a map file actualiza-tion

Additionally a complete SVET scanning of the recog-nized real pits areas can be performed if the corrosion ratedetermination is necessary The VI performing the videoinspection and the creation of the map file only is the subjectof the present work while the SVET VI is the subject ofanother publication

2 Systemrsquos Hardware Configuration

Three main devices were involved in the system hardwareconfiguration a video inspection mighty scope near infrared10xndash200x 13MP 141015840 CMOS color 6 LED light type oper-ating at 850 nm USB 20 interfaced digital microscope witha homemade lineal stage focus controlling mechanism inthe range from 85mm to 112mm with stepper motor NPMPF35-24C1 a homemade SVET device with X-Y stagesstepper motors VEXTAmodel PX245M-01A and a personalcomputer Dell Optiplex 7010 Core i7 CPU 340GHzWindows 8 Pro operating system as illustrated in Figure 1

The optical inspection by a digital microscope allows thecapturing of full images from 4mm2 to 1700mm2 (opticalzoom in the range from 10x to 200x) respectively of thestudied surface with a resolution of 1600 to 1200 effectivepixels at shot speed user controllable from 1 to 11000 secThefocus adjustingmechanism (Y stage Figure 1) was driven by astepper motor controlled by the LCIAwhich controls also thereal time image capturing and its transfer through the USBinterface The white balance was carried out automaticallyemploying the integrated 6 white LED light ring around thelenses

The homemade SVET device [15] which uses the map fileproduced by the VI subject of the present work consists ofa vibrating electrode with edge diameter of approximately1 120583m 100mV p-p and frequency of the vibration of 60Hz


Stepper motor

Digital microscope

Sample


Personal computer

USB

USB



Sample

USB


119884

119884

stage

119883

119883-119884 stages




3 Programming






VI system

ADIPCL

StopYes

Yes Yes



Focus Umbral adjust

Save and stop


NoNo











4 Applications







5 Conclusions








(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Stepper motor

Digital microscope

Sample


Personal computer

USB

USB



Sample

USB


119884

119884

stage

119883

119883-119884 stages




3 Programming






VI system

ADIPCL

StopYes

Yes Yes



Focus Umbral adjust

Save and stop


NoNo











4 Applications







5 Conclusions








(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


VI system

ADIPCL

StopYes

Yes Yes



Focus Umbral adjust

Save and stop


NoNo











4 Applications







5 Conclusions








(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






5 Conclusions








(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of







(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


(a)

(b)



Acknowledgments


References





























Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of






















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of










Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

Documents

Research Article LabVIEW 2010 Computer Vision Platform