How does Matlab find its centroids?

I'm given an image of a migrating tissue and am supposed to index them in order to track their movement. I know how to use Matlab's regionprops to get the coordinates of each cell's centroid, but there doesn't seem to be an apparent pattern in how those are acquired. What is the mechanism behind the regionprops centroid function? Ie, does it sweep left to right, up to down, etc?

Here is a list of the x & y coordinates of each centroid.

2. 2.72222222222222 12.3148148148148
3. 1.33333333333333 36.6666666666667
4. 7.24157303370787 52.0168539325843
5. 11.6112600536193 72.5576407506703
6. 1.21428571428571 88.3571428571429
7. 5.12048192771084 107.144578313253
8. 10.6801152737752 130.953890489914
9. 1 129.500000000000
10. 4.42857142857143 152.027210884354
11. 1 170
12. 2.15789473684211 177.526315789474
13. 1.28571428571429 200.142857142857
14. 2.60784313725490 213.529411764706
15. 11.3271889400922 227.488479262673
16. 9.49162011173184 190.329608938548
17. 18.3308687615527 41.3659889094270
18. 15.7302325581395 167.144186046512
19. 12.3804347826087 92.2391304347826
20. 17.1487179487179 210.353846153846
21. 18.4343065693431 8.59489051094891
22. 23.7884615384615 106.205128205128
23. 28.2996389891697 149.891696750903
24. 27.7061611374408 194.099526066351
25. 25.3571428571429 177.446428571429
26. 31.0265486725664 28.8539823008850
27. 33.6319218241042 77.2996742671010
28. 27.8437500000000 216.843750000000
29. 37.3181818181818 126.033492822967
30. 36.5258620689655 226.327586206897
31. 39.4915966386555 97.5378151260504
32. 40.3189189189189 160.756756756757
33. 40.7327044025157 10.1823899371069
34. 44.1309523809524 204.468253968254
35. 46.3154034229829 54.7114914425428
36. 47.2241992882562 181.839857651246
37. 50.3228346456693 144.102362204724
38. 67.5563909774436 24.8928571428571
39. 62.8309859154930 216.827464788732
40. 48.5000000000000 233
41. 53.7386363636364 82.3750000000000
42. 56.4951456310680 50.0097087378641
43. 59.4615384615385 102.750000000000
44. 61.2985074626866 161.626865671642
45. 59.5708661417323 9.24409448818898
46. 65.6092715231788 183.066225165563
47. 74.2796052631579 118.651315789474
48. 70.7100840336134 87.3235294117647
49. 82.0454545454546 41.0580808080808
50. 70.0823529411765 67.1529411764706
51. 78.5631067961165 188.184466019417
52. 79.1071428571429 3.30357142857143
53. 94.7543859649123 207.309941520468
54. 77 233
55. 88.9041095890411 135.566210045662
56. 91.7504873294347 175.397660818713
57. 84.8169014084507 96.3521126760563
58. 96.3712121212121 225.762626262626
59. 88.0093457943925 59.1962616822430
60. 92.3858695652174 82.0760869565217
61. 95.3484848484848 9.92727272727273
62. 89.9152542372881 114.813559322034
63. 104.529616724739 151.097560975610
64. 101.526315789474 68.1578947368421
65. 103.969491525424 104.593220338983
66. 109.338842975207 24.3595041322314
67. 110.425867507886 48.1829652996845
68. 107.038834951456 124.864077669903
69. 112.188235294118 136.541176470588
70. 116.375545851528 83.8646288209607
71. 114.843930635838 175.965317919075
72. 117.733590733591 198.401544401544
73. 118.117647058824 7.10294117647059
74. 127.271186440678 65.9898305084746
75. 121.375000000000 161.275000000000
76. 118.972222222222 219.638888888889
77. 122.918367346939 231.326530612245
78. 129.454849498328 125.053511705686
79. 127.118556701031 27.8969072164948
80. 127.444444444444 146.581196581197
81. 125.939393939394 104.878787878788
82. 123 1
83. 133.982978723404 48.1234042553192
84. 136.648351648352 85.3076923076923
85. 132.219512195122 187.463414634146
86. 136.664835164835 207.714285714286
87. 138.382488479263 168.156682027650

Answer 1

[Image Analyst]

I would think it's the average of all the x coordinates and the average of all the y coordinates. That's the usual formula. It does not matter at all how those coordinates are arrived at.

There is also a weighted mean which weights the coordinates by the gray level at that coordinate.