Visual Inspection of Cylindrical Product s Lateral Surface using Cameras and Image Processing

Transcription

1 Vsual Inspecton of Cylndrcal Product s Lateral Surface usng Cameras and Image Processng Mohammed A.H. Al, M. Malah, H.H. Tang and S. Kaz Abstract Vsual nspecton usng cameras s used here for testng the lateral surface of cylndrcal products. The nspecton can be carred out accordng to avalable resources by: lne scan camera system, matrx camera wth concal mrror system and matrx camera wth mult flat mrrors system. The research s amed to use the prevous systems for testng the objects surface and makng comparson between the mentoned systems. Ths requres sutable settng of each system to perform experments and gettng mages, ncludes: settng of camera, lght, object and mrrors. The mage of each system has a dfferent vew from each other and t s qute dffcult to make drectly comparson between them. For ths reason, the mages should have the same vew for ts lateral surface, so called the developed vew. The mage of the lne scan camera s used as a reference for the developed vew and the mages comng from matrx camera wth concal mrror and mult flat mrrors are manpulated usng mage processng n MATLAB program to fnd the developed vew of lateral surface of the nspected object. The developed vew of the mages from the prevous systems s compared n terms of ther resoluton and accuracy, for the same tested object, n order to choose whch system s sutable for the nspecton task. Keywords Concal mrrors, mage processng n MATLAB, lne scan camera, matrx camera, multple flat mrrors. T I. INTRODUCTION HE fnshng surface of ndustral parts such as shafts, bearngs, pstons, rngs and pns should be smooth wthn the permssble lmts before nstallaton process, as the defects n these parts may damage or reduce the lfe of machne. There are several nspectons methods that can be dvded nto two groups: Destructve nspecton methods (DT), Nondestructve testng (NDT), dependng on the requred degree of surface smoothness and the presence of defects n crystallne structure of these parts. Vsual test s one of the famous methods of non destructve tests. It gves the possblty to detect the defects lke: shape defects, corrosons, fatgue cracks and leaks at dfferent stages durng the producton process, whch eventually results n tme-savngs and lower fnancal costs. Manuscrpt receved January 3, All authors are wth the Department of System Dynamcs and Control, Faculty of Mechancal Engneerng, Unverst Teknolog Malaysa, UTM Johor Bahru, Johor MALAYSIA. E-mals(moh-al-hashm@maktoob.com,musa@fkm.utm.my, tanghh@fkm.utm.my, skaz75@gmal.com) Ths test can be carred out ether by naked eye nspectons (not applcable and naccurate), or by nspectons wth the use of endoscope, magnfyng glass and cameras. Several researches have been done n the area of automatc vsual nspecton for testng the surface objects whch can be from smple surface lke sheets to complex lke cylndrcal, mult-shape objects. Zhang et al. presented an automatc vson system to detect and classfy surface defects due to the processes of grndng and polshng [1]. Omar et al. has provded a system capable of self-adjustment pantng booth operaton for an automotve fuel tank producton, based on the defects detected by automatc nspecton system [2]. Ja et al. proposed a real-tme vsual nspecton system that uses vector machne to automatcally learn complex defect patterns [3]. Norfum et al. nnovated a new method based on an optcs model for hghly relable surface nspecton of ndustral parts [4]. Sun et al. proposed a real-tme magng and detecton system for weld defects n steel tubes [5]. Rosat et al. presented an automatc defects detecton for coated plastc component n automotve ndustry [6]. Laurowsk et al. and Demoynek et al. have proposed 3D objects nspecton systems that can be used for path plannng and localzng these products durng machnng operatons [7, 8, 9]. In ths research, lne scan and matrx camera system were used to vsually nspect the lateral surface of cylndrcal object aganst surface defects. Lne scans camera system gves the opportunty to perform mage acquston of cylndrcal object's surface lne by lne, whle matrx camera system s well suted for text recognton and mage processng n one-frame unt. Two systems are desgned to nspect the cylndrcal objects usng matrx camera: - Camera wth concal mrror. - Camera wth multple flat mrrors. The mages from the cameras should be manpulated by mage processng programs n order to ether mprove ts pctoral nformaton for human nterpretaton or for autonomous machne percepton [10]. The processng of mages n ths project has been done usng specal codes n MATLAB, whch stores mages as matrces, n order to make these mages sutable for utlzng n comparson step between the three systems wth a condton that ensure good extractng of features. Issue 2, Volume 6,

2 II. LINES SCAN CAMERA SYSTEM A lne scan camera s an mage capturng devce havng a CCD sensor whch s formed by a sngle lne of photosenstve elements (pxels). The lne scan camera should be used n applcatons where hgh resoluton mages are requred, and for nspectng the objects whch moves lke sheet (contnuous processng). The hardware of ths system as llustrated n Fg. 1, conssts of the followng parts: 1- Lne scan camera wth lens: DALSA S H40, base camera lnk wth 8 bt wth CCD 512 pxels, C-Mount. 2- Holder of camera whch mantans the camera n the correct poston of object. 3- Holder of object wth capablty of rotaton usng stepper motor. 4- Holder of lght to produce homogeneous lght. III. MATRIX CAMERA SYSTEM Matrx camera s an array mage sensor, whch uses a rectangular mosac of pxels to capture an mage. Ths camera works well to capture the large objects smaller than the feldof-vew of a camera. Two expermental setups for performng ths nspecton system are employed, namely, the matrx camera system wth concal mrror system and matrx camera system wth multple flat mrrors system as explaned n the followng sectons. A. Matrx Camera System wth Concal Mrror System The hardware components of ths system as shown n Fg. 3a nclude the followng parts:- 1- Matrx camera: the camera used for ths purpose s JAI CV- M1 wth ( ) pxels CCD sensor, C-Mount. 2- Concal mrror: the angle of ths cone s 45, dameter of bottom base s 11mm. 3- Base body. 4- Holder of mrror. 5- Holders of camera. 6- Holders of object. 7- Holders of lght Fg. 1: Lne scan camera system A number of experments have been done consderng dfferent cylndrcal objects wth varyng heghts and dameters. The settng of the experment for the lne scan camera was as follows: The dstance between the lens and the nspected object s 200 mm and the dstance between the lght source and the nspected object s 150 mm. The lens used s TAMRON wth magnfcaton 1:3.9, dameter of the lens, Ø=25.5 mm, focal length=75mm. The mage for the object s shown n Fg. 2a whle Fg. 2b depcts the mage by usng the lne scan camera system. Fg. 3: Matrx camera wth concal mrror system. Close vew of concal mrror. The mage of the object n Fg. 2a s shown n Fg. 4 through matrx camera wth concal mrror. Fg. 2: Horzontal and vertcal lnes pattern on cylndrcal object (D=11 mm, H=30 mm). Image acqured of ths object by lne scan camera. Issue 2, Volume 6,

3 Fg. 4: Image of cylndrcal object n matrx camera wth concal mrror system. B. Matrx Camera System wth Multple Flat Mrrors System The multple flat mrrors system as shown n Fg. 5a conssts of the followng parts:- 1- Matrx camera: the camera s JAI CV-M1 wth ( ) pxels CCD sensor, C-Mount. 2- Multple flat mrrors: fve mrrors (50mm 20mm 3mm) supported by holders on the rng usng taped glue as n Fg. 5b. 3- Rng wth 16 dvson angle: A range wth outer radus=167mm and nner radus=120mm wth thckness 15mm) gves us a possblty to dvde the range nto sxteen sectors (each one can hold mrror). 4- Connecton beams: fve beams (80mm 20mm 8mm) connect the holder of mrrors to rng. 5- Mrror holders t has ncdence of Object holder: cylndrcal part wth 50 mm n dameter and wth 200mm n heght s supported n the exact mddle of range. 7- Base body. 8- Holders of cameras. 9- Holders of lght. Fg. 6: Image of cylndrcal object n matrx camera wth multple flat mrrors system. IV. DEVELOPED VIEW OF MATRIX CAMERA'S IMAGES In order to compare the prevous nspecton systems, to decde whch one s sutable for ths project, there s a need to make a graphc model wth smlar development vew of the three systems, whch produce the cylndrcal object n a rectangular shape, snce ths vew s able to produce enormous nformaton for defects of objects, as shown n Fg. 2b. Ths s due to the fact that the mages taken from these systems cannot be compared drectly, as shown n Fgs. 2b, 4 and 6. The mages of the cylndrcal object n lne scan camera are used as reference as shown n Fg. 2b and the mages from matrx camera are processed n MATLAB to fnd the rectangular developed vew. A. Developed Vew of Matrx Camera wth Concal Mrror The mages from the matrx camera wth concal systems have to be processed through two steps, n order to extract the developed rectangular vew: 1) Mathematcal model: The cylndrcal object can be descrbed n cylndrcal coordnate system as shown n Fg. 7. z z p x y θ Fg. 7: Cylndrcal object coordnate system. From Fg. 7, any pont p n the lateral surface of object has n cylndrcal coordnate system the followng dmensons as n Eqs. 1-3: Fg. 5: Matrx camera wth multple flat mrrors system. ( b) Close vew of mult flat mrrors. The mage resulted from settng n Fg. 2a s shown n Fg. 6. x = r cosθ y = r sn θ z = z (1) (2) (3) Issue 2, Volume 6,

4 INTERNATIONAL JOURNAL OF MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES Where θ s the angle between the orgnal coordnate system and the choosng pont. r s the radus of the object and t has constant value. z s the heght of ths ponts n the drecton of z startng from 0 to h heght of the object. Ths lateral crcumference surface of the object occurs n the camera's mage lke a dsk shape as shown n Fg. 8. y1 to a rectangle vew. The ntermedate step s to transfer every crcular lne n the dsk nto horzontal straght lne. The factor used for transferrng the crcular sector lne (as shown n Fg θ 9a) to a straght lne s 2πR 360 (Fg. 9.b). Then the straght (h tan α + r) lnes n Fg. 9b are stretched usng the factor, (z tan α + r), n order to make the bottom surface of the object looks lke the upper surface as shown n Fg. 9c. R θ x1 (c) Fg. 9: Steps for transferrng mage's vew of object to developed vew (c.) At the end, the developed vew of the whole lateral surface can be descrbed n Cartesan coordnate system, x2,y2 as shown n Fg. 10. Fg. 8: Camera's mage of cylndrcal object n the mage coordnate system. x2 Any ponts n the prevous dsk can be descrbed n the mage coordnate system x1,y1 as depcted n Fg. 8 by Eqs. 4 and 5 as follows: x1=r cos θ y1=r sn θ y2 (4) (5) Fg. 10: Developed vew of the lateral surface of object Where R s the radus of the dsk startng from the nner radus of dsk to the outer radus of dsk. Note: The nner radus of the dsk n the mage = radus of the object, takng nto consderaton the effect of the lens. The value of R n the mage coordnate system can be found usng r and z from the cylndrcal object coordnate system takng nto consderaton the magnfcaton effect of the lens and the type of camera used. Ths effect s called the factor of lens and camera fc. R can be calculated from Eq. 6 as follows: R=fc (z tan α+r) (6) Where α s the concal mrror angle. If the value of R from Eq. 4,5 s compensated n Eq. 6, one gets Eq. 7,8: x1=fc (z tan α+r) cos θ y1=fc (z tan α+r) sn θ (7) (8) y 2 = 2πfc (z tan α) x 2 = fc z tan α θ (h tan (αα+ r) 360 (z tan (αα+ r) (9) (10) Any pont n the coordnate system of the cylndrcal object x, y, z can be transferred to the mage coordnate system x1, y1 and the developed vew coordnate system x2, y2, and vce versa. 2) MATLAB Algorthm: The MATLAB algorthm conssts of the followng steps: - Readng and croppng the mage wth the dmensons descrbed n Eq. 11: x=y= 2(br) (11) Where, (br) s the largest crcular lne, as shown n Fg Transferrng of the symmetrcal rotatng lnes to normal straght lnes: The lateral surface of the nspected cylndrcal object s shown n Fg. 4 as crcular lnes. The equaton of the In order to get the lateral crcumference surface of the cylndrcal object as the mage of lne scan camera vew, the dsk vew comng from mage coordnate system s developed Issue 2, Volume 6, 2012 Any pont of the developed vew of ths object can be descrbed n Cartesan coordnate system of the developed vew x2 and y2 as llustrated n Eqs. 9 and

5 crcle generates postve and negatve values, and unfortunately, the MATLAB mage processng program can deal only wth postve values. Therefore, the crcle s dvded nto four sectons as descrbed n Eqs as follows: Frst quarter: ( Sx- x)²+ (Sy- y)²= r ² Second quarter: Thrd quarter: Fourth quarter: ( x-sx)²+ ( x-sx)²+ (Sy- y)²= (y -Sy)²= 2 ( Sx-x)²+ (y -Sy)²= r 2 r 2 r (12) (13) (14) (15) Fg. 13: Stretch of lnes from to done by MATLAB program. Where, (Sx, Sy) s the center of the crcle (known). From the above equatons, and n order to fnd the value of thrd varable, the value of the two varables should be known. Also, n order to ncrease the accuracy and avod squared hghest values, every quarter s dvded nto two sectons as shown n Fg Fltraton: As the values of the pxel s coordnate system must be always be an nteger n MATLAB, the approxmatng values should be derved from Eqs Two dmensonal order statstc flters were used for ths purpose as shown n Fg. 14. (c) Fg. 11: Combnng the left half and rght half to get the frst quarter (c). Then, every crcular lne has to be transferred to a normal lne by usng specal assgnment code n MATLAB as shown n Fg. 12. Fg. 14: The effects of Two Dmensonal Order flter Image before flter Image after flter. The two sectons of these quarters must be reflected, as shown n Fg. 15. Fg. 12: Transferrng step of crcular lnes nto straght lnes. In the prevous step, the outcome of the straght lnes as shown n Fg. 12b have no smlar length, so a measurng scale algorthm s used. If the length of the lnes from the bggest radus s br and from the smallest radus sr, the measurng scale s as expressed n Eq. 16 as follows: Fg. 15: Half secton of the quarter need to reflect Reflecton of ths secton. The collectons of the quarters n one frame are the developed vew of the matrx camera wth concal mrror as shown n Fg. 16. ms=br/(br- sr+ 1 ) (16) The result s llustrated n Fg. 13. Issue 2, Volume 6,

6 INTERNATIONAL JOURNAL OF MATHEMATICAL MODELS AND METHODS IN APPLIED SCIENCES ψ 4 = ψ and ffth mrror ψ 4 = ψ The angle between axes zrf of the global coordnate system and the partal coordnate of the partal mrrors zr s α whch s equal to 45 n ths settng. The partal coordnate system can be descrbed n relatve to the global coordnate system as gven n Eq. 20. x r 0 cos α y r = 0 sn α z r 1 0 Fg. 16: Developed vew of the object n matrx camera wth concal mrror. B. Developed Vew of the Matrx Camera wth Multple Flat Mrrors The mages from the matrx camera wth fve flat mrrors systems have to be manpulated through two steps, n order to extract the developed rectangular vew: 1) Mathematcal model: The prevous cylndrcal object as depcted n Fg. 7 can be nspected usng fve flat mrrors wth one camera system. Any pont on the crcumference of the cylndrcal object can be descrbed n a coordnate system, the so called real coordnate system xrf, yrf and zrf as expressed n Eqs xrf = r cos θ yrf = r sn θ zrf = z sn α cos ψ cos α sn ψ 0 0 sn ψ 0 xrf cos ψ 0 yrf 0 1 zrf (20) The partal axes (xr, yr) descrbe the vew of the object n the mrrors, where zr descrbe the thckness of mrrors. The prevous descrpton usng 3D coordnate system s useful for descrbng the settng of the system, but t s not useful to descrbe mage n the partal mrrors because the mage has only two axes coordnate system. Therefore the coordnate system wth two axes s used to fnd the poston of every ponts n the mage of the cylndrcal object, thus t s called the mage coordnate system. Each partal mrror's mage can be descrbed by specal two axes coordnate system as shown n Fg. 18. (17) (18) (19) ypf x Where θ changes from 0 to 360. r s the radus of the object and t has constant value. z s the heght of the object and t changes from 0 at the bottom base of cylndrcal object to h whch s the top part of the cylndrcal object. The object and the settng of the partal mrror are descrbed n global coordnate system by fve partal coordnate system as shown n Fg. 17: xpf y yrf Fgure 18: Coordnate system of partal mrrors and fxed mage coordnate system zrf xr yr x, y specal coordnate system for each mrror. xpf, ypf fxed mage coordnate system. The mage coordnate system apples to the real coordnate system mentoned above wth a scale related to the knd of camera and lens used as descrbed by Eqs xrf zr zrf xpf = fc. xrf ypf = fc. yrf y = fc. y r. cos α x = fc. x r. sn α Fg. 17: Global coordnate system and partal coordnate system n mult flat mrrors The angle between the axes xrf, yrf of the global coordnate system and the partal coordnate (xr, yr) s explaned as Any pont n these mrrors can be descrbed n specal coordnate of each mrror as follows: Every crcular lnes n object wll occur as straght horzontal lnes n mrrors (see Fg 19), and therefore we can fnd that n follows: For frst mrror, the angle s ψ 1, the second mrror, ψ 2 = ψ , the thrd mrror ψ 3 = ψ , fourth mrror Issue 2, Volume 6, 2012 (21) (22) (23) (24) 345

7 the deal case, ths straght lnes have the same length wth the dameter of the crcle,.e., 2R. β R Image wdth n partal mrrors Mrror Object zrf Base zrf.ctan Fg. 19: Image wdth of cross secton of object n partal mrror Length of object n partal mrror. Ths length can be descrbed usng the specal coordnate system of each mrror as gven n Eq. 25. x = R cos β and y = fc.zrf.c tan α (25) Where β changes from 0 to 180 n every specal coordnate system. R = fc.r s the radus of the object n the mage coordnate system whch s greater than r (radus of the object) by a factor fc (the effect of camera and lens). α s the angle of mrrors n z drecton. It s notced that some parts of the mage occur twce and n order to capture the parts whch occur only once n each mrror, the pentagon dmensons and angles should be derved as shown n Fg 20a. The requred pentagon s one n whch the fve sdes are located nsde of crcle as shown n Fg. 20b. α x = Rcosβ 54 β 126 (26) The poston of any pont n each mrror coordnate system can be calculated n the mage coordnate system. The total angle of mrrors locaton n relaton to the mage coordnate system can be calculated usng Eq. 27: ϕ = ψ + ω (27) Where ψ s the constant angle for each mrror descrbed before. ω s the rotatonal angle of whole system about the reference mage coordnate system. The pont p on the crcumference of the object can be descrbed n the mage coordnate system for those parts whch occur only once n each related partal mrrors as gven n Eq. 28. xpf cos ϕ sn ϕ x + t = = ypf sn ϕ cos ϕ y + g cos ϕ sn ϕ fc.r cos β + t sn ϕ cos ϕ fc.zrf.c tan α + g (28) Where ϕ + 36 θ ϕ 36, t s the shftng of every partal mrror axes to the center of mage coordnate system n x drecton. g s the shftng of every partal mrror axs to the center of mage coordnate system n y drecton. The fve partal vews of the mage n mrrors are collected n one vew, whch looks lke those shown n Fg. 21. It can be descrbed n the so called collectng coordnate system, xcf, ycf and the relatonshp between xf, yf and xcf, ycf wll be descrbed by Eq. 29 as follows: ycf = ypf (29) xcf = xpf + (30) u 72 Actual wdth of mrror's mage 36 R where u s accumulatng wdth of the mrrors that can be calculated as follows: u1=0; u2=w; u3=u2+w=2w; u4=u3+w=3w; u5=u4+w=4w, where w s the actual wdth of the mrror (see Fg. 20b). Eqs can be rewrtten as descrbed n Eq. 31 as follows: 54 Fg. 20: Geometrcal propertes of pentagon Property of fve partal mrror system From Fg. 19, the angle β should be changed between (54 and 126 ) to ensure that the wdth of the mage n each partal mrror can occur only once, whch can be calculated usng Eq. 26 as follows: xcf cos ϕ sn ϕ x + t + u = = ycf sn ϕ cos ϕ y + g cos ϕ sn ϕ fc.r cos β + t + u sn ϕ cos ϕ fc.zrf.c tan α + g Where ϕ + 36 θ ϕ 36 (31) Issue 2, Volume 6,

8 ycf w vertcal drecton and then cuts the nterested captured mage, as shown n Fg. 22. u2 u3 u4 u5 Mrror1 Mrror2 Mrror3 Mrror4 Mrror5 xcf Fg. 21: Scheme of the developed vew of mult flat system The mrrors coordnate system can be descrbed n the real object coordnate system takng nto consderaton the factor related to the types of cameras and lens fc. Thus, Eqs can be wrtten n real coordnate system usng the followng transformaton as descrbed n Eq. 32. x + t cos ϕ sn ϕ xrf = fc. y + g sn ϕ cosϕ yrf (32) Where ϕ + 36 θ ϕ 36 From prevous Eqs , f any pont of the object s known n real coordnate system (xrf, yrf, zrf), t's poston can be found n partal coordnate system (x, y) and mage coordnate system (xpf, ypf), vce versa. 2) MATLAB Algorthm: In order to get the mage from the fve partal mrrors system as shown n Fg. 5, t should be ntally marked on the base, the global coordnate system (xrf, yrf, zrf) and a partal mrror coordnate system of all the mrrors (x, y, z). The camera axes should be focused at the center of the object. The followng algorthm s used for manpulatng the mage n ths system: - Readng, croppng and rotatng mage for the partal mrrors. - Capturng the mage of object n each mrror: The axes of the partal mrrors should meet each other at the center of object. Due to some deformaton n the hardware system, some correcton n angles of the mrrors has been done. Eq. 33 s used to capture every mrror mage: d x = y tan ϕ ± 2 (33) Where, ϕ = ψ + ω, ψ s a constant angle for each mrror and dependng on the pentagon propertes ψ + 1 = ψ x and y are the coordnate system of each mrror. ω s the rotatonal angle of the whole system around the reference mage coordnate system, d s the dameter of the object. Due to the prevous captured mage from every mrror postoned at a certan angle, the program rotates ths mage tll t s n Fg. 22: The fve captured partal mages of object. - Regstraton: Specal regstraton has been done for the partal vew of mrrors n relaton to the calculaton of the equal sdes of pentagon wth condtons that the center of tested part meets the center of mrrors axes. The capturng wdth of object n all mrrors s equal to the dameter of the tested part nserted by the user. The software program calculates the angles from the frst mrror axes, whch are ncrementally ncreased by (360 /5= 72 ). As the mrrors are supported n rng wth an angle 72 between them respectvely, the dfference between the hardware and software measurement s small. The actual wdth for each mrror s calculated dependng on the property of the pentagon (wth equal sdes). The fnal regstraton of ths tested object s llustrated n Fg. 23. Fg. 23: Developed vew of regstraton the partal vews of mrrors usng program n MATLAB. The accuracy of the regstraton between the fve partal mrrors s shown n Fg. 24. Issue 2, Volume 6,

9 resoluton, whereas the developed vew through the use of matrx camera wth concal mrror has good resoluton and accuracy whle that wth fve flat mrrors gves good resoluton but bad accuracy. REFERENCES a c d Fg. 24: Pattern of letters that covered cylndrcal object. Image from the matrx camera wth multple flat mrrors. (c) Cover before placng on object. (d) Developed vew of the partal vews of mrrors after mage processng. V. COMPARISON BETWEEN INSPECTION SYSTEMS A number of experments have been done for nspectng the objects n these systems. The horzontal and vertcal lnes pattern object of Fg. 2a s llustrated va the lne scan camera shown n Fg. 2b. Smlarly, the developed vew of the matrx camera wth concal mrror and fve flat mrrors are shown n Fgs. 16 and 23, respectvely. The mage resoluton of these objects s best observed n the lne scan camera system n comparson to the matrx camera counterpart. The accuracy of the mage wth the effect of non-homogeneous lghtng that s acqured by the fve mrrors s relatvely not as effcent as the mproved concal mrrors, but the lne scan camera system has the best accuracy. VI. CONCLUSION The lne scan camera system should be used to nspect the cylndrcal object wth mult-dameters components as t produces hgh resoluton mages for nspected object and accurate mages wthout dstortons for some applcatons. On the other hand, the matrx camera should be used for faster applcaton and t saves more power compared to the lne scan camera whch requres the rotaton of the object, accumulatng lght and adjustng the camera feld. The matrx camera wth concal mrror has some advantages over the mult flat mrrors system n whch the former produces a full feld vew of the object compared to the latter system. However, the matrx camera wth mult flat mrror system should be used nstead of the concal mrror system to nspect the objects havng dfferent dameters. The comparson between these systems n terms of the resoluton and accuracy s always sgnfcant, dependng on the results of the experments, for the same tested objects. The mage produces by the lne scan camera has the best accuracy and best b [1] Zhang X, Krewet C, Kuhlenkoetter B. ''Automatc classfcaton of defects on the product surface n grndng and polshng''. Internatonal Journal of Machne Tools Manufacture, Vol. 46, No. 1, 2006,pp [2] Omar M, Vt V, Sato K, Lu J. Self-adjustng robotc pantng system. Internatonal Journal of Industral Robot; Vol. 33, No. 1, 2006, pp [3] Ja H, Murphey YL, Sh J, Chang T-S. ''An ntellgent real-tme vson system for surface defect detecton''. In: Proceedngs of the 17th nternatonal conference on pattern recognton, Cambrdge, UK, August 23 26, [4] Norfum K, Mutsuo S, Shuch O, Masash O. ''A method for nspectng ndustral parts surfaces based on an optcs model''. Journal of Machne Vson and Applcatons, Vol. 12 No. 4, 2000, pp [5] Sun Y, Ba P, Sun Hy, Zhou P. ''Real-tme automatc detecton of weld defects n steel ppe''. NDT&E Internatonal, Vol. 38, No. 7, 2005, pp [6] Rosat G, Boschett G, Bond A and Ross A. ''Real-tme defect detecton on hghly reflectve curved surfaces''. Optcs and Lasers n Engneerng Vol. 47, 2009, pp [7] M. Weyrch, P. Klen, M. Laurowsk, Y. Wang, Vson based Defect Detecton on 3D Objects and Path Plannng for Processng, Proceedngs of the 9th WSEAS Internatonal Conference on ROCOM [8] O. Demuynck, C. P. Cedeno, A. L. Moore, Industral Machne Vson System for Fast and Precse 3D Object Localzaton, n Proceedngs of the 9th WSEAS Internatonal Conference on Sgnal Processng, Computatonal Geometry and Artfcal Vson, [9] M. Weyrch, M. Laurowsk, P. Klen, and Y. Wang..''A Real-tme and Vson-based Methodology for Processng 3D Objects on a Conveyor Belt''. In WSEAS Internatonal Journal of Systems Applcatons, Engneerng & Development Issue 4, Vol. 5, [10] Gonzalez R, Woods R and Eddns S. Dgtal Image Processng Usng MATLAB. Prentce Hall [11] M. Al, M. Malah, S. Kaz and T. Hng. '' Defects Detecton of Cylndrcal Object's Surface Usng Vson System''. In Proceedng of The 10th WSEAS Internatonal Conference on Computatonal Intellgence, Man-Machne Systems and Cybernetcs (CIMMACS '11), Jakarta, 1-3 December, Issue 2, Volume 6,