Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 58 Meaurement of the State of Hole With One Exoure Uing a Single Digital Camera CHIN-TUN CHUANG, MING-CHI LU, CHEN-CHIEN HSU 3, YIN-YU LU 4 Deartment of Mechanical an Comuter-Aie Engineering, St. John Univerity, 499 Tam King R., Sec. 4, Tam-Sui, Taiei County, 535 Deartment of Electronic Engineering, St. John Univerity, 499 Tam King R., Sec. 4, Tam-Sui, Taiei County, 535 3 Deartment of Electronic Engineering, Tamkang Univerity 5 Ying-chuan Roa, Tamui, Taiei County, 537 4 Deartment of Comuter Science an Information Engineering, Nation Central Univerity, Taoyuan County, 300 Abtract: - In thi aer, a novel meauring metho for examining the tate of a ingle rille through-thickne hole in term of exact urface roughne, reciion tolerance, eccentricity i reente. The rooe metho can alo meaure the iameter an eth of the hole with one exoure uing a ingle igital camera. It i the aim of thi aer to evelo a new camera oitioning control evice which utilize the forementione meauring metho to reuce exene an roce time uring the meaurement. We eigne the aaratu accoring to an etablihe frame of igital camera meaurement arameter (height of otic oition an with of horizontal view angle). The effectivene of the rooe aroach in meauring the iameter an eth of the through hole ha been valiate by uing gray cale chromatic aberration of the image contour region. Thi meaurement ytem not only increae the accuracy of the meauring reult but i alo alicable with any kin of igital camera. Key-Wor: - meaurement frame, through-thickne hole, igital camera. Introuction Currently, there are many kin of meauring gauge in ue for meauring the iameter a well a the eth of hole in mechanical fabrication inutry. The mot oular meauring gauge i Vernier Calier []-[] which require two te, by meauring the iameter an eth reectively. Other meauring gauge uch a ultraonic wave [3]-[4] an laer beam [5]-[7], too, can be ue for thi meaurement uroe, however, they are claime not being very uer frienly. Meauring gauge mae with a LVDT i alo available [8]-[9]; neverthele, none of the above can rovie a viual image contour region of the rille through-thickne hole an how the meauring ata of iameter an eth of throughthickne hole at one time. A mentione earlier, the goal of thi reearch i to eign a meauring metho that allow the meaurement of through-thickne hole iameter an eth at one hot. It i worthwhile noting that the metho oe not require any hyical contact of the two object (rille through-thickne hole an meauring gauge) to avoi any cratch or any other negative imact. A igital camera with two high intenity LED light i intalle above the hole to be meaure to rovie a viual efinition. Only the to an the bottom of the through-thickne hole are hotograhe which will how a in two ifferent ize roun image contour region. The imenion of the roun image contour region will equal the total ixel it take an bae on the reult, the iameter an eth of the rille through-thickne hole can then be calculate. The econ ection will exlain the reaon we believe the meaurement of hole iameter an eth can be one in one hot. We continue to elaborate on the formula in the thir ection. In the fourth ection, we will rove the ajutment frame
Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 59 eigne i alicable to all kin of igital camera with the correct meaurement arameter. Section five an ix will jutify the formula an calculation roce with an exeriment an followe i the concluion in ection.3. Theory of hole iameter an eth meaurement A mot igital camera effective ixel have reache to the level over 6 million [0]-[] an equie with lighting thee ay, a clear cloe u can be eaily taken even when the illumination i minimal. For a hole with 0mm iameter, total ixel taken in it viual image contour region will be over 000 an the reolution of itance meaurement will reach below 0μm. It i becaue of all the function mentione above intalle in nowaay igital camera, thi reearch can then be ractice an comlete. The following ection will introuce the meaurement concet an tructure with actual viual image contour region taken to rove it accuracy. High Intenity LED Digital Camera θ o Dm h o h h A hown in Figure, attach the igital camera with two high intenity LED light (in orer to rovie enough illumination for a clearer image contour region outut) to the meauring frame at height h. Now the itance between the igital camera an the very bottom of the hole to be meaure become h hence the hole-eth Hm equal to h- h. Elaboration on how to calculate the hole-eth (Hm) an hole-iameter (Dm) will be inclue in the later ection. When the igital camera hotograh from to own, the viual reult will how two roun gray cale contour region. The larger one being the to of the hole a it i cloer to the camera (h) an the maller one i the bottom of the hole which i more itant from the camera (h). The imenion of the two roun gray cale contour region can be ue to etermine the total ixel taken in the viual image contour region an then obtain the hole-iameter an hole-eth meaurement by alying the formula introuce next. In Figure, ho i the height of the otic oition an θ enote the with of horizontal view angle. Both are the meaurement arameter an by utilizing the ajutment tructure eigne in thi tuy, ifferent meaurement arameter can then be calculate een on which kin or bran of igital camera in ue, i.e. the tructure i alicable to all igital camera. We will now look at the actual image contour region in the icture taken to exlain why the imenion of image contour region can be ue to calculate the actual hole-iameter an hole-eth. Figure an 3 give a comarion between the image contour region of two ifferent rille through-thickne hole (in term of iameter an Hm h o :Height of otic oition h :Ditance between the to of the hole an igital camera D m :Hole iameter of amle H m :Hole eth of amle h : h + H m Fig. Schematic iagram of ytem for hole iameter(d m ) an eth (H m ) meaurement. Hole-iameter of amle: mm Hole-eth of amle: 4.9mm Fig. actual image contour region of amle Ⅰ
Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 60 Dm. When uing the triangular theorem to etermine the relationhi between the horizontal itance an height: Hole-iameter of amle: mm Hole-eth of amle: 0.3mm Fig. 3 actual image contour region of amle Ⅱ. eth) an it i obviou that the imenion of two roun image contour region in each viual reult vary. It i worthwhile noting that when hoto-grahing the hole-contour, there i no nee to focu on the center of the circle (hole). A long a the two gray cale contour region fit into one creen, the meaurement can then be one. Both A in Figure an 3 are the image contour region of the hole-urface an B are the holebottom. In later ection, we will icu how to etermine how many ixel an area of image contour region (A & B) take.. Formula for meaurement In orer to give a clear exlanation, we will enlarge the grahic an go through the formula auming the camera hotograh at the center of the contour region (hole). Diameter(D m ) will remain the ame regarle of anything an accoring to our reviou invetigation [3]-[6]. Since the can time an horizontal itance are in irect roortion, hence the total ixel taken will alo grow when the horizontal itance exten when uing a igital camera for meaurement. N (max) D ( h ) = D () m N( D(h) i the maximum horizontal itance when the height i at h an the horizontal angle i at θ. In the cae of viual image contour region, the maximum amount of ixel taken for every horizontal line canne i enote a N (max) an with the hole iameter (urface of the hole) being Dm, N(h) rereent the number of total ixel taken for Fig. 4 Schematic iagram of meaurement frame. h = D( h )cotθ h o () From () an () we then erive the following formula N( h ) ( ho + h ) Dm = (3) N (max) cotθ Since N (max) ha been etermine, we will then exlain how to utilize the ajutment tructure to obtain the meaurement arameter for the igital camera. Auming ho an cotθ are alo known an h being the height that the uer can ecie, thi leave N(h) to be the only variable in the formula. Therefore, once N(h) i etermine, the hole iameter Dm can then be calculate. From Figure an 3, there will be 3 ifferent gray cale contour region. In the center, the viual contour region i the hole-bottom, the next contour region i the vertical inner ie of the hole an followe by the urrouning of the hole-urface. When comaring the outut in term of gray cale chromatic aberration, the ifference between Figure 5 an 6 can be eaily itinguihe. N(h) an N(h) enote the iameter of the two circle (to an bottom of the rille through-thickne hole reectively) hown below:
Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 6 A N( N( B K th Scan Line Fig. 5 ifferentiation of image contour region Ⅰ. The unknown eth H m =h -h N (max) N (max) H m = Dm cotθ [ ] (7) N( N( From Formula 3, the iameter of the hole ha been calculate an from Formula 7, the eth of the rille through-thickne hole i alo etermine. Thi truly achieve what we ha rooe earlier, to have the meaurement reult of the iameter an eth at one time through the hole viual image contour region outut. N( N( Vertical Scale h o A B K th Scan Line Fig. 6 ifferentiation of image contour region Ⅱ. We calculate the total ixel taken for the um of all roun image contour region intea of uing the one with the bigget quantity of ixel for iameter calculation. AN(h) an AN(h) rereent the um of ixel for the two roun image contour region (urface an bottom of the hole with N(h) an N(h) being the iameter of each) an from the formula ue to calculate the imenion of a circle, we erive the following: AN( AN( N ( h ) =, N( h ) = (4) π π We chooe the above way to etermine N(h) an N(h) i becaue it i bae on the ame concet of uing the metho of mean (average). Thi i to avoi mijugment an ultimately to increae the meaurement accuracy. For the art of hole-bottom, the height to where the camera i remain to be h an the iameter of which alo tay till (Dm). At height h, the igital camera houl have the maximum horizontal itance which i: N (max) D( = D m (5) N(h ) h then become h = D( h) cotθ ho N (max) = ( ) Dm cotθ N( h) h (6) o P P Horizontal Scale θ Dm Dm Fig. 7 Ajutment Structure. Q Q. Etablihing the meaurement arameter When lacing the horizontal meaurement gauge between P an Q, the itance obtaine i h m an ame alie when meauring the itance (h m ) between P an Q. The horizontal itance for both cae i D m. = Dm cotθ h O (8) = D m cotθ h S O (9) From (8) an (9) we get Dm Dm ho = (0) D D cot m h h m m m θ = () Dm Dm Aly the meaurement arameter ho an cotθ into formula 3 an 7, we will be able to get Dm an Hm reectively.
Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 6.3 Pixel calculation bae on the gray cale contour region outut Figure an 3 are the viual outut we obtaine when meauring the hole an Figure 5 an 6 enote the borer of the circle which are one bae on the ifference of gray cale chromatic aberration. Thi will allow u to know to which extent the ixel are to be calculate. There are four chromatic aberration on the canning-line of image contour region. A B cae cae cae 3 cae 4 Fig. 8 Jugment rule of ixel calculation. From Figure 8, we are able to know that ixel taken for each line canne. Therefore, every time when Figure 5 an 6 are canne, the um of the total ixel for the two image contour region will be known imultaneouly [AN(h) an AN(h)] which can then be utilize for N(h) an N(h) calculation by aoting formula 4. Regaring the ixel calculation, there are ifferent alication available. However, we have taken the ifference in term of meaurement arameter for ifferent igital camera into conieration an conclue with an eaiet jugment rule an calculation metho. An exeriment i conucte to rove that the metho i ractical to erve the meaurement uroe an more etail will be rovie in the next ection. 3 Exeriment reult A. Scheme of exeriment () The igital camera i PANASONIC Electric Inutrial Co., Lt. Lumix DMC-FZ30 Tye. () N (max)= 04 ixel. (3) Meaurement arameter uggete by meaurement frame ho+ h = 48.99 mm, cotθ=.. (4) Detail of the hole of amle to be meaure a Table We rille everal through-hole from variou teel late with ifferent thicknee. With the eth of each hole being known (each teel late thickne), we then meaure every hole-iameter by uing a meauring gauge an label them iniviually. Table contain the meaurement reult of the iameter an eth of each hole rouce in the amle No of 3 4 5 6 amle Actual hole iameter (mm) Actual hole eth (mm) N(h ) (ixel) N(h ) (ixel) Value of hole iameter meaurement (mm) Value of hole eth meaurement (mm) Error value of hole iameter meaurement % Error value of hole eth meaurement % 4 Concluion 5 5 5 9 0. 4.9 0.3 4.9 4.9 0.3 76.356.535.3.5356.635. 338.339.6339.04.847.47.3 5.33 5.4 5.378.7.4.37 0.965.87.655.935.87.03..68.49 -.48 -.69 -.85 7.43 6.88 6.9 7.8 6.85 8.80 In thi aer The metho of meaurement for meaure iameter an eth of hole by uing only one igital camera. We eign an aaratu of meaurement ytem that alie to any kin of igital camera which allow two imenional meaure to be achieve bae on the image contour region outut a long a the meaurement arameter uggete by the ytem are correctly being aote. The error of meaurement value i within the accetance range an it alo hel in checking the tate of holeurface through image contour region outut.
Proceeing of the 007 WSEAS Int. Conference on Circuit, Sytem, Signal an Telecommunication, Gol Coat, Autralia, January 7-9, 007 63 Thi ytem of meaurement will be economical an ortable for hole-rilling fabrication. Reference: [] htt://www.mitutoyo.com/prouct Tye Reult Form.ax tye=33. [] htt://www.mitutoyo.com/prouct Tye Reult Form.ax tye=36. [3] Aleio Carullo, Franco Ferrari, an Salvatore Graziani, Ultraonic Ditance Senor Imrovement Uing a Two-Level Neural Network, IEEE Tranaction on Intrumentation an Meaurement, Vol. 45, No.,.677-68, Aril 996. [4] A. Caarullo an M. Parvi, An ultraonic enor for itance meaurement in automotive alication, IEEE Senor J., Vol., no. 3,.43-47, Oct. 00. [5] K. Ougi, K. Miyauchi, N. Furui, an H. Miyakohi, Develoment of the canning laer rather for ACC ytem, JSAE Rev. 0,.579-554, 999. [6] Y. M. KlimKov, A laer olarmetric enor for meauring angular ilacement of object, in Proc. Eur. Conf. Laer an Electro-Otic, Se. 8-3, 996,.90-90. [7] C.-C. Peng, A Comact Digital Image Sening Ditance an Angle Meauring Device, M.S. thei, Taoyuan County, Taiwan, Ot. Sci. Center, Nation Central Univ., Taiwan, R.O.C., 00. [8] G.Y. Tian, Z.X. Zhao, R.W. Baine, an P. Corcoran, The eign of miniaturie ilacement tranucer for ee hole iameter meaurement, Mechatronic,.37 37, 999. [9] G.Y. Tian, Z.X. Zhao, R.W. Baine, an P. Corcoran, A miniaturie enor for ee hole iameter meaurement, Preciion Engineering 3,.36 4, 999. [0] CANON igital IXUS 60 camera, with the effective ixel in aroximately 6.0M, an the cloet focu itance range from 5cm to 50cm. [] PANASONIC igital LUMIX FX3 camera, with the effective ixel in aroximately 6.0M, an the cloet focu itance by 5cm. [] FUJIFILM igital F30 camera, with the effective ixel in aroximately 6.3M, an the cloet focu itance range from 5cm to 80cm. [3] M.-C. Lu, W.-Y. Wang, an H.-H. Lan, Image- bae height meauring ytem for Liqui or article in tank, in Proc. IEEE Int. Conf. Networking, Sening an Control, vol., 004,.4-9. [4] M.-C. Lu, W.-Y. Wang, an C.-Y. Chu, Otical-Bae Ditance Meauring Sytem (ODMS), The Eighth International Conference on Automation Technology, 005,.8-83. [5] M.-C. Lu, Image-bae height meauring ytem for Liqui or article in tank, ROC atent of invention, No. 0536, 004. [6] Ming-Chih Lu, Wei-Yen Wang, an Chun-Yen Chu, Image-Bae Ditance an Area Meauring Sytem, IEEE Senor Journal, vol. 6, no.,.495-503, Aril 006.