What is Chrome's Circularity ?
- Analysis on Glass and Ceramic Target
Chrome on ceramic calibraiton plate and chrome on glass calibration plate as below have same circle array pattern.
The circle pattern profile, or circularity here, of two plates are compared. One plate is made of glass with chrome pattern. Another one is made of ceramic. An industrial camera system, 20Mega pixel camera with a telecentric lens, are used to capture images of both plates.

- Find circle edge points from dark-to-bright transission;
- A best-fit circle is found based on edge points;
- Distances of actual edge points to their ideal edge locations are calculated;
- For a same circle, circularity value can be deduced absed on these distances;
Circularity Results - Chrome on Glass Calibration Target | ||
---|---|---|
Circle 01/μm | Circle 02/μm | Circle 03/μm |
0.930355217 | 0.882166867 | 0.745621688 |
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Circularity Results - Chrome on Ceramic Calibration Target | ||
---|---|---|
Circle 01/μm | Circle 02/μm | Circle 03/μm |
1.632780942 | 2.001454584 | 1.740648624 |
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Original Data

Figure 1: distance tolerance of ceramic circle/μm

Figure 2: distance tolerance of glass circle/μm
Ceramic Plate Circularity
circle edge points to its best-fit circle/μm
circle edge points to its best-fit circle/μm
Circle 1 Tolerance | Circle 2 Tolerance | Circle 3 Tolerance |
---|---|---|
0.690279699 | -0.154455564 | -0.198290834 |
0.051954771 | -0.048769763 | 0.362189014 |
-0.181674373 | 0.25432293 | -0.12970735 |
-0.252535435 | 0.065962548 | 0.2970796 |
-0.038615636 | -0.228296616 | -0.06482041 |
0.050049835 | 0.004864981 | 0.616196767 |
0.063070369 | 0.429784191 | 0.616196767 |
-0.022962989 | -0.645827212 | -0.154196086 |
-0.521039056 | -0.114397137 | -0.067476698 |
0.400277808 | -0.495253159 | -0.08585265 |
-0.052620713 | -0.020316403 | 0.004737328 |
-0.14806614 | -0.152180218 | 0.138382664 |
0.035103911 | -0.090652639 | 0.08742304 |
0.011147296 | 0.055159523 | -0.005504426 |
-0.330031932 | -0.330863685 | 0.911506222 |
0.556199511 | 0.301711589 | 0.078344887 |
0.189384886 | -0.10398427 | 0.045048007 |
0.399707331 | -0.122508274 | -0.212919503 |
-0.079561022 | 0.806084643 | 0.046858827 |
-0.051900985 | -0.14948442 | 0.187946108 |
0.223336638 | -0.366543421 | 0.090138193 |
-0.193835993 | 0.268406048 | 0.575024272 |
0.151630013 | -0.129058214 | 0.0995647 |
0.147328844 | 0.004403614 | 0.253648531 |
0.257288588 | -0.035368305 | -0.297348971 |
-0.206824271 | 0.222924939 | -0.07909764 |
0.42549509 | 0.201559821 | 0.050687959 |
-0.044355988 | -0.016820575 | -0.43317066 |
-0.205556109 | 0.116559245 | 0.027722161 |
-0.152868248 | -0.322613138 | -0.392895313 |
-0.143310089 | 0.122550277 | -0.322531505 |
-0.085816675 | 0.152550588 | -0.192290387 |
-0.314980973 | -0.359728465 | -0.242197383 |
-0.277037561 | 0.640154717 | 0.031903433 |
-0.753476357 | 0.442074953 | -0.218983773 |
0.036935189 | 0.103744964 | -0.040421537 |
0.207899669 | -0.868538614 | 0.009062739 |
0.538969105 | -0.259102955 | -0.309538552 |
0.122081202 | -0.534710905 | -0.370262057 |
-0.424167064 | 0.050268728 | -0.168215191 |
0.282819128 | -0.349193367 | 0.085858305 |
-0.189896761 | -0.209985101 | 0.064843084 |
0.025357879 | -0.009824665 | -0.238702843 |
-0.381121826 | 0.559349493 | -0.094212577 |
0.224083157 | -0.573418351 | 0.178920688 |
-0.147860483 | 1.00754664 | 0.361478261 |
0.307762952 | -0.078827971 | -0.208886889 |
0.462937101 | -0.08256025 | 0.606995549 |
-0.266459582 | 0.21870932 | 0.278074584 |
0.035327109 | 0.07165238 | 1.007222509 |
0.448863109 | 0.157227298 | 0.251022586 |
-0.241471726 | 0.056469147 | 0.143042311 |
0.063353319 | 0.577329831 | 0.280984718 |
0.879304585 | -0.307497544 | 0.126182953 |
-0.062138555 | 0.216043089 | -0.201351034 |
0.004244868 | -0.349725533 | 0.02569446 |
-0.259675877 | 0.045112968 | 0.716333921 |
-0.369388946 | -0.595577621 | -0.006254585 |
-0.18926684 | -0.515742989 | 0.004922716 |
0.501757286 | -0.037214137 | -0.515821836 |
0.187229484 | -0.001080541 | -0.509758098 |
-0.114377074 | 0.748157599 | -0.455592075 |
-0.715297474 | -0.306307933 | -0.733426115 |
-0.133331586 | -0.504360517 | -0.437174242 |
-0.429654388 | 1.13291597 | -0.553970541 |
Glass Plate Circularity
circle edge points to its best-fit circle/μm
circle edge points to its best-fit circle/μm
Circle 1 Tolerance | Circle 2 Tolerance | Circle 3 Tolerance |
---|---|---|
0.091995961 | 0.050258151 | 0.130265936 |
-0.169715055 | -0.029823 | 0.114100118 |
-0.21416425 | -0.070387738 | 0.077060318 |
-0.01142235 | -0.009703095 | 0.251599688 |
0.003859566 | 0.038180366 | 0.111241407 |
-0.097560225 | 0.157394146 | 0.077939498 |
0.13359006 | -0.15500293 | -0.091290406 |
0.033398475 | -0.160039311 | -0.084630405 |
-0.056321212 | -0.088112065 | 0.140543844 |
0.15607994 | -0.022261369 | 0.101283485 |
-0.043852083 | -0.479280449 | 0.060230889 |
0.24610395 | -0.001501942 | 0.02681445 |
-0.286774453 | -0.269254764 | -0.03510439 |
0.05835938 | -0.215635766 | 0.170371682 |
0.1208963 | 0.103831788 | 0.141598408 |
0.152811544 | 0.068478188 | 0.180770229 |
0.198294141 | 0.029427128 | 0.05978146 |
0.199588578 | 0.247820192 | -0.16448023 |
0.272684222 | -0.003986382 | 0.157125903 |
0.40783353 | -0.154998635 | 0.048317561 |
0.235040734 | 0.223389077 | 0.004587461 |
0.191184431 | 0.045486546 | 0.14728261 |
0.036707914 | 0.136829844 | -0.089203279 |
0.01949872 | 0.117883342 | -0.316826537 |
-0.033760779 | 0.207696686 | -0.085870582 |
0.023017749 | 0.047578671 | -0.157511871 |
-0.185901721 | -0.006294775 | -0.040820262 |
-0.082355358 | 0.100473711 | -0.148631652 |
-0.399342093 | -0.040110269 | -0.231112887 |
-0.131754926 | 0.010610411 | -0.165372541 |
-0.194473762 | -0.057159163 | -0.0583752 |
-0.178428809 | 0.017813329 | -0.141940781 |
-0.348457199 | 0.001381945 | -0.080989144 |
-0.112934797 | -0.006396027 | -0.060257957 |
-0.074978826 | -0.017771296 | -0.042830084 |
-0.317458118 | -0.205891414 | 0.180725428 |
0.11238122 | -0.252349085 | -0.087568832 |
-0.174936528 | 0.127660439 | 0.029227841 |
-0.297581625 | -0.129305142 | 0.254315806 |
0.019494976 | -0.118563885 | 0.282422472 |
0.066060583 | -0.028193321 | 0.146287693 |
-0.031706697 | -0.049549018 | 0.221890137 |
0.09633944 | 0.140416656 | 0.257098642 |
0.021318125 | 0.028780256 | -0.117512106 |
0.531013124 | -0.103020072 | 0.37712237 |
0.408258166 | 0.19777205 | 0.187553074 |
0.477641638 | -0.116846798 | 0.196647944 |
0.260511255 | -0.152405934 | 0.057588359 |
0.345117281 | 0.012694822 | 0.141985857 |
0.318479556 | -0.136572258 | 0.179337105 |
0.336655505 | 0.102757585 | -0.368499318 |
-0.046208571 | -0.032642637 | -0.036120826 |
-0.125247794 | -0.077709626 | -0.280441258 |
-0.061718187 | 0.402886417 | -0.060777036 |
-0.102055852 | -0.012168314 | -0.221940423 |
-0.247502303 | 0.097478346 | -0.168554537 |
-0.149994388 | -0.064579099 | -0.162200331 |
-0.083605477 | 0.027320993 | -0.365483307 |
-0.0881842 | 0.0472734 | -0.202338465 |
-0.321358346 | -0.090186506 | -0.202067386 |
-0.250556665 | -0.006732071 | -0.060910069 |
-0.069956847 | 0.102934286 | -0.003998168 |
-0.148409271 | 0.130665361 | -0.000275401 |
-0.069956847 | 0.113847932 | -0.003998168 |
-0.148409271 | 0.113847932 | -0.000275401 |
-0.171076391 | 0.135872544 | -0.219888512 |