Microscopy and Image Analysis Based Approaches for the Species-Specific Identification of Bovine and Swine Bone Containing Material

Figures & data

Figure 1. Examples of swine (Sus scrofa) (A) and bovine (Bos taurus)(B) bone lacunae at X40 magnification.

Figure 2. Key steps in lacunae measurements. Reproduced with permission of Prof. L. Pinotti (Pinotti, 2009).

Figure 3. Box plots showing selected primary descriptors (lacunae axis major and perimeter) in bovine (bov) and swine (sus) species. Diamond represents mean; line within the box is the median; circle stand for the outlier.

Figure 4. Box plots showing selected derived shape descriptors (lacunae aspect and roundness2) in bovine (bov), and swine (sus) species. Diamond represents mean; line within the box is the median; circle stand for the outlier.

Table 1. Primary descriptors used in the experiment.

ID	Variable	Description
V1	Area, µm^2	Area of the object, includes area of the hole if fill holes is turned on
V11	Axis major, µm	Length of major axis of ellipse
V12	Axis minor, µm	Length of minor axis of ellipse
V13	Diameter max, µm	Length of longest line joining two points of the object’s outline and passing through the centroid
V14	Diameter min, µm	Length of shortest line joining two points of the object’s outline and passing through the centroid
V15	Diameter mean, µm	Average length of diameters measured at 2 degree intervals and passing through the object’s centroid
V16	Radius max, µm	Maximum distance between object’s centroid and outline
V17	Radius min, µm	Minimum distance between object’s centroid and outline
V19	Perimeter, µm	Length of the object’s outline. More accurate than previous version. Old version now called perimeter2
V28	Size (length), µm	Feret diameter (i.e. caliper length) along major axis of object
V29	Size (width), µm	Feret diameter (i.e. caliper length) along minor axis of object
V30	Perimeter2, µm	Chain code length of the outline. It also includes any outlines of holes. Faster but less accurate than perimeter
V32	Perimeter (convex), µm	Perimeter of the convex outline of the object
V33	Perimeter (ellipse), µm	Perimeter of the equivalent ellipse
V35	Polygon area, µm^2	Area included in the polygon defining the object’s outline. Same polygon as that used for perimeter
V40	Box width, µm	Width of the object’s bounding box
V41	Box height, µm	Height of the object’s bounding box
V42	Min feret, µm	Smallest caliper (feret) length
V43	Max feret, µm	Longest caliper (feret) length
V44	Feret mean, µm	Average caliper (feret) length
V57	Convex area, µm^2	Area of a polygon which has major axis and minimum axis for sides

Table 2. Derived shape descriptors used in the experiment.

ID	Variable	Description
V2	Aspect	Ratio between major axis and minor axis of the ellipse equivalent to object
V3	Area/box	Ratio between area of object and area of its bounding box
V4	Box X/Y	Ratio between width and height of object’s bounding box
V20	Radius ratio	Ratio between max and min radius
V21	Roundness	(Perimeter2)/(4π area). It uses perimeter2 and area by default. Select perimeter and area for more accurate roundness
V34	Perimeter ratio	Ratio of convex perimeter to perimeter
V55	Form factor	4π area/perimeter2
V56	Roundness2	4π area/axis major2
V58	Solidity	Area/convex area

Table 3. Mean and standard deviation by species of all lacunae primary descriptors measured.

ID	Variable	BOV		SUS		P
		Mean	SD	Mean	SD
V1	Area, µm^2	102.15	33.64	93.85	27.77	0.0105
V11	Axis major, µm	18.24	3.30	16.35	3.71	<0.0001
V12	Axis minor, µm	7.33	2.12	7.50	1.67	0.3826
V13	Diameter max, µm	18.85	3.54	16.74	3.89	<0.0001
V14	Diameter min, µm	6.74	1.89	6.91	1.46	0.3396
V15	Diameter mean, µm	11.30	1.50	10.86	1.37	0.0043
V16	Radius max, µm	10.04	1.89	9.04	2.17	<0.0001
V17	Radius min, µm	3.01	0.94	3.09	0.76	0.3364
V19	Perimeter, µm	49.91	10.82	45.14	11.15	<0.0001
V28	Size (length), µm	19.15	3.58	17.11	3.97	<0.0001
V29	Size (width), µm	8.30	2.39	8.23	1.90	0.7549
V30	Perimeter2, µm	53.79	11.93	48.62	12.19	<0.0001
V32	Perimeter convex, µm	44.53	7.10	40.91	7.79	<0.0001
V33	Perimeter ellipse, µm	42.24	6.27	38.97	6.87	<0.0001
V35	Polygon area, µm^2	96.28	32.75	88.48	26.88	0.0134
V40	Box width, µm	14.65	4.80	13.78	4.61	0.0822
V41	Box height, µm	14.18	4.83	12.68	4.23	0.0017
V42	Feret (min), µm	8.17	2.33	8.10	1.80	0.7446
V43	Feret (max), µm	19.20	3.56	17.18	3.95	<0.0001
V44	Feret (mean), µm	14.30	2.26	13.14	2.48	<0.0001
V57	Convex area, µm^2	132.80	43.93	121.96	36.66	0.0109

BOV, bovine; SUS, swine; SD, standard deviation.

Table 4. Mean and standard deviation by species of all lacunae derived shape descriptors measured.

ID	Variable	BOV		SUS		P
		Mean	SD	Mean	SD
V2	Aspect	2.74	1.06	2.31	0.86	<0.0001
V3	Area/box	0.54	0.11	0.58	0.09	<0.0001
V4	Box X/Y	1.26	0.80	1.28	0.77	0.7802
V20	Radius ratio	3.76	1.68	3.18	1.46	0.0005
V21	Roundness	2.27	0.69	2.00	0.97	0.0033
V34	Perimeter ratio	0.88	0.07	0.90	0.06	0.0623
V55	Form factor	0.53	0.14	0.60	0.14	<0.0001
V56	Roundness2	0.41	0.15	0.48	0.15	<0.0001
V58	Solidity	0.77	0.01	0.77	0.02	0.4597

BOV, bovine; SUS, swine; SD, standard deviation.