Application of Image Analysis Combined with Computational Expert Approaches for Shrimp Freshness Evaluation

Figures & data

FIGURE 1 A: Lighting chamber for image capturing; B: shrimp side pictures; and C: shrimp top pictures.

TABLE 1 The variables extracted from the images captured

Variable	Description
mean_l	means of lightness
mean_a	means of redness
mean_b	means of yellowness
mean_h	means of lightness hue
mean_s	means of saturation
mean_v	means of value
Rcontrast	Red color contrast
Rhomogeneity	Red homogeneity
Renergy	Red energy
RCorrelation	Red Correlation
Rentropy	Red entropy
Gcontrast	Green color contrast
Ghomogeneity	Green homogeneity
Genergy	Green energy
GCorrelation	Green Correlation
Gentropy	Green entropy
Bcontrast	blue color contrast
Bhomogeneity	blue homogeneity
Benergy	blue energy
BCorrelation	blue Correlation
Bentropy	blue entropy
Hcontrast	hue color contrast
Hhomogeneity	hue homogeneity
Henergy	hue energy
HCorrelation	hue Correlation
Hentropy	hue entropy
Scontrast	saturation contrast
Shomogeneity	saturation homogeneity
Senergy	saturation energy
SCorrelation	saturation Correlation
Sentropy	saturation entropy
Vcontrast	value contrast
Vhomogeneity	value homogeneity
Venergy	value energy
VCorrelation	value Correlation
Ventropy	value entropy
glcmRmean	means of Red gray-level co-occurrence matrix (GLCM)
glcmGmean	means of Green gray-level co-occurrence matrix (GLCM)
glcmBmean	means of blue gray-level co-occurrence matrix (GLCM)
glcmHmean	means of hue gray-level co-occurrence matrix (GLCM)
glcmSmean	means of saturation gray-level co-occurrence matrix (GLCM)
glcmVmean	means of value gray-level co-occurrence matrix (GLCM)

TABLE 2 Statistics of the variables

Variable no.	Name of variable	Mean	Std	Asymmetry	Minimum	Maximum	Range
49	glcmRrange	704797	143686	1.1603	296717	1418603	1121886
52	glcmGrange	629731	178345	1.3374	360667	1404951	1044284
58	glcmHrange	593060	158837	1.8553	347863	1326154	978291
64	glcmVrange	605333	176884	1.4446	351729	1317575	965846
55	glcmBrange	607804	174330	1.4575	359247	1320592	961345
61	glcmSrange	603266	120685	2.2910	439472	1199375	759903
51	glcmRvar	43494	7248	2.9193	35727	80564	44837
66	glcmVvar	43006	7423	3.0559	36275	80878	44604
57	glcmBvar	42982	7432	3.0706	36368	80851	44483
54	glcmGvar	43038	7529	3.0425	36009	80325	44316
60	glcmHvar	43709	7518	3.0834	37400	81523	44123
63	glcmSvar	43702	7097	3.0399	37881	79049	41168
50	glcmRmean	16345	2734	3.1304	14198	29981	15784
53	glcmGmean	16345	2734	3.1304	14198	29981	15784
56	glcmBmean	16345	2734	3.1304	14198	29981	15784
59	glcmHmean	16345	2734	3.1304	14198	29981	15784
62	glcmSmean	16345	2734	3.1304	14198	29981	15784
65	glcmVmean	16345	2734	3.1304	14198	29981	15784
4	l_var	4422	802	0.4824	2988	6771	3783
9	b_range	52.91	12.34	0.1697	23.00	82.00	59.00
7	l_range	235.6	8.3	0.1011	219.0	255.0	36.0
1	mean_l	32.27	5.82	0.5965	19.98	53.02	33.04
8	a_range	33.43	2.11	0.4930	28.00	40.00	12.00
3	mean_b	127.9	0.4	0.2737	127.1	129.2	2.1
6	b_var	127.9	0.4	0.2737	127.1	129.2	2.1
2	mean_a	128.3	0.4	0.0035	127.4	129.2	1.8
5	a_var	128.3	0.4	0.0035	127.4	129.2	1.8
16	h_range	0.7121	0.1866	-0.4920	0.3157	0.9302	0.6146
17	s_range	0.6347	0.1339	-0.0895	0.3251	0.9000	0.5749
38	Hentropy	0.1270	0.1231	0.5932	0.0000	0.4489	0.4489
18	v_range	0.6642	0.1049	-0.6649	0.4039	0.8471	0.4431
21	Renergy	0.4840	0.0831	-0.7829	0.2141	0.6387	0.4245
26	Genergy	0.4133	0.0959	0.2830	0.2555	0.6319	0.3764
43	Sentropy	0.948	0.064	-2.5883	0.625	1.000	0.375
46	Venergy	0.3953	0.0969	0.5437	0.2653	0.6351	0.3698
31	Benergy	0.3960	0.0941	0.4959	0.2654	0.6222	0.3568
36	Henergy	0.3979	0.0631	0.4650	0.2810	0.5524	0.2714
34	Hcontrast	0.3004	0.0610	0.3345	0.1764	0.4474	0.2710
12	mean_v	0.3113	0.0345	0.4643	0.2232	0.4274	0.2042
41	Senergy	0.4747	0.0455	1.0477	0.4126	0.5932	0.1806
10	mean_h	0.5243	0.0287	0.4050	0.4823	0.5810	0.0987
37	HCorrelation	0.9001	0.0176	-0.2222	0.8550	0.9377	0.0827
19	Rcontrast	0.0547	0.0154	1.1051	0.0286	0.1101	0.0815
24	Gcontrast	0.0638	0.0194	0.2229	0.0291	0.1050	0.0759
11	mean_s	0.1247	0.0183	-0.0882	0.0923	0.1619	0.0696
44	Vcontrast	0.0643	0.0181	0.0513	0.0310	0.0996	0.0687
29	Bcontrast	0.0647	0.0172	0.0399	0.0316	0.0966	0.0651
42	SCorrelation	0.9150	0.0134	-0.3285	0.8824	0.9428	0.0604
23	Rentropy	0.992	0.010	-1.8335	0.954	1.000	0.046
20	Rhomogeneity	0.9729	0.0077	-1.1184	0.9450	0.9858	0.0407
25	Ghomogeneity	0.9683	0.0096	-0.2190	0.9481	0.9855	0.0373
39	Scontrast	0.0489	0.0091	0.7569	0.0334	0.0706	0.0372
28	Gentropy	0.994	0.007	-1.7581	0.965	1.000	0.035
33	Bentropy	0.994	0.007	-1.6124	0.965	1.000	0.035
48	Ventropy	0.994	0.007	-1.7600	0.965	1.000	0.035
45	Vhomogeneity	0.9681	0.0089	-0.0425	0.9509	0.9845	0.0337
30	Bhomogeneity	0.9679	0.0085	-0.0338	0.9524	0.9842	0.0318
27	GCorrelation	0.9863	0.0047	-1.4909	0.9690	0.9923	0.0233
15	v_var	0.0352	0.0048	0.0964	0.0253	0.0479	0.0226
32	BCorrelation	0.9859	0.0046	-1.2468	0.9710	0.9923	0.0213
13	h_var	0.0227	0.0042	0.7387	0.0155	0.0345	0.0190
40	Shomogeneity	0.9757	0.0045	-0.7191	0.9650	0.9837	0.0187
47	VCorrelation	0.9876	0.0039	-1.1195	0.9758	0.9932	0.0173
35	Hhomogeneity	0.9729	0.0036	0.2514	0.9655	0.9815	0.0160
22	RCorrelation	0.9892	0.0031	-0.9453	0.9795	0.9948	0.0153
14	s_var	0.0026	0.0007	0.3683	0.0015	0.0044	0.0029

TABLE 3a General fisher weights

Order	Variable	FW	Index of variable
1	mean_s	1.81768	11
2	mean_a	1.80385	2
3	a_var	1.80385	5
4	mean_h	1.39050	10
5	s_var	1.34800	14
6	mean_v	1.16282	12
7	glcmHrange	1.03916	58
8	glcmGrange	0.93738	52
9	HCorrelation	0.81493	37
10	Genergy	0.79556	26
11	glcmBrange	0.77957	55
12	Senergy	0.76862	41
13	glcmVrange	0.76339	64
14	l_var	0.75940	4
15	mean_b	0.75889	3
16	b_var	0.75889	6
17	Shomogeneity	0.73622	40
18	Scontrast	0.72532	39
19	Venergy	0.71213	46
20	Benergy	0.71163	31
21	Hhomogeneity	0.71087	35
22	a_range	0.68911	8
23	Gcontrast	0.65230	24
24	Ghomogeneity	0.64979	25
25	l_range	0.59323	7
26	Henergy	0.56208	36
27	mean_l	0.55357	1
28	glcmGvar	0.53779	54
29	glcmRrange	0.53547	49
30	glcmRvar	0.53230	51

TABLE 3b Fisher weights for categories 1 and 2

Order	Variable	FW	Index of variable
1	mean_v	2.59850	12
2	mean_a	1.93064	2
3	a_var	1.93064	5
4	l_range	1.75111	7
5	Benergy	1.30074	31
6	Venergy	1.27149	46
7	l_var	1.25436	4
8	mean_b	1.23805	3
9	b_var	1.23805	6
10	Genergy	1.19190	26
11	glcmGrange	1.18379	52
12	glcmBrange	1.16927	55
13	glcmVrange	1.12184	64
14	Vhomogeneity	1.02947	45
15	Vcontrast	1.01744	44
16	Bhomogeneity	0.95099	30
17	Bcontrast	0.93443	29
18	Ghomogeneity	0.87467	25
19	Gcontrast	0.86510	24
20	Hcontrast	0.83693	34

TABLE 3c Fisher weights for categories 1 and 3

Order	Variable	FW	Index of variable
1	mean_h	4.78273	10
2	mean_a	4.41163	2
3	a_var	4.41163	5
4	s_var	2.96057	14
5	mean_s	2.34845	11
6	a_range	1.86517	8
7	mean_b	1.86026	3
8	b_var	1.86026	6
9	b_range	1.67028	9
10	Benergy	1.48839	31
11	Genergy	1.43653	26
12	Venergy	1.42884	46
13	l_var	1.42454	4
14	glcmGrange	1.14411	52
15	l_range	1.09884	7
16	glcmBrange	1.06012	55
17	glcmVrange	1.02242	64
18	Ghomogeneity	1.01079	25
19	Gcontrast	0.99278	24
20	mean_v	0.98523	12

TABLE 3d Fisher weights for categories 1 and 4

Order	Variable	FW	Index of variable
1	mean_a	3.69438	2
2	a_var	3.69438	5
3	s_var	3.00501	14
4	mean_v	2.97945	12
5	glcmGrange	2.21970	52
6	Genergy	2.04087	26
7	Gcontrast	1.93656	24
8	mean_s	1.93081	11
9	Ghomogeneity	1.90340	25
10	mean_h	1.84934	10
11	glcmBrange	1.74047	55
12	glcmVrange	1.72916	64
13	l_var	1.72656	4
14	Shomogeneity	1.72620	40
15	mean_l	1.72268	1
16	Scontrast	1.69613	39
17	Venergy	1.45227	46
18	Benergy	1.37783	31
19	Senergy	1.26653	41
20	glcmGvar	1.24111	54

TABLE 3e Fisher weights for categories 2 and 3

Order	Variable	FW	Index of variable
1	mean_s	3.48230	11
2	glcmHrange	1.37913	58
3	a_range	1.02949	8
4	Senergy	0.99950	41
5	mean_h	0.97335	10
6	h_range	0.92599	16
7	s_var	0.91014	14
8	Henergy	0.73503	36
9	b_range	0.63133	9
10	mean_a	0.50438	2
11	a_var	0.50438	5
12	Shomogeneity	0.50384	40
13	Scontrast	0.50109	39
14	Renergy	0.45628	21
15	RCorrelation	0.43315	22
16	glcmSrange	0.33341	61
17	Rhomogeneity	0.22344	20
18	Rcontrast	0.22223	19
19	glcmRrange	0.21576	49
20	Ventropy	0.18419	48

TABLE 3f Fisher weights for categories 2 and 4

Order	Variable	FW	Index of variable
1	mean_s	3.04445	11
2	glcmHrange	2.22633	58
3	HCorrelation	1.81717	37
4	Henergy	1.57999	36
5	h_range	1.40807	16
6	Senergy	1.39403	41
7	Hhomogeneity	1.36529	35
8	Shomogeneity	1.33794	40
9	Scontrast	1.31480	39
10	s_var	1.01352	14
11	glcmHvar	0.91585	60
12	glcmRvar	0.88849	51
13	glcmGvar	0.88571	54
14	glcmRmean	0.86399	50
15	glcmGmean	0.86399	53
16	glcmBmean	0.86399	56
17	glcmHmean	0.86399	59
18	glcmSmean	0.86399	62
19	glcmVmean	0.86399	65
20	glcmBvar	0.84295	57

TABLE 3g Fisher weights for categories 3 and 4

Order	Variable	FW	Index of variable
1	Hhomogeneity	1.77240	35
2	HCorrelation	1.55413	37
3	a_range	1.13129	8
4	v_range	1.04548	18
5	glcmRvar	1.01147	51
6	glcmHvar	0.98419	60
7	glcmRrange	0.96354	49
8	glcmSvar	0.91367	63
9	glcmRmean	0.91199	50
10	glcmGmean	0.91199	53
11	glcmBmean	0.91199	56
12	glcmHmean	0.91199	59
13	glcmSmean	0.91199	62
14	glcmVmean	0.91199	65
15	glcmGvar	0.90864	54
16	glcmVvar	0.88552	66
17	glcmBvar	0.88193	57
18	glcmHrange	0.74522	58
19	glcmGrange	0.61882	52
20	Hcontrast	0.57892	34

FIGURE 2 Cultured shrimp color changes during storage on ice.

FIGURE 3 The color change of four groups of pacific white shrimps (litopenaeus vannamei) during 9 days of storage on ice.

FIGURE 4 Variation of shrimp color parameters from side pictures during storage on ice; A: r, g, and b; B: h, s, and v; C: L*, a*, and b*; and D: c and h.Day: 1 = first day, 2 = third day, 3 = sixth day, 4 = ninth day; h = hue, c = chroma.

TABLE 4 Fisher weights of a single category (mean of three FW between pairs of categories), for some variables and the most discriminant sums of standardized variables

Variable or sum	Indexes	For class 1	For class 2	For class 3	For class 4
a_range	8			1.34
a_var	5	3.35	0.86	1.68	1.33
a_var+b_range	5 + 9	3.65
a_var+mean_s	5 + 11	4.34		3.30
a_var+s_var	5 + 14	5.10
glcmHrange	49	1.52	1.34		1.40
Henergy	36		0.96
mean_a+glcmGrange	2 + 49
mean_h	10	2.27		1.92
mean_s	11		2.18	1.97	1.69
mean_v	12	2.19	0.92
s_var	14	2.05		1.29	1.34
s_var+Hhomogeneity	14 + 35				3.02
v_range+Shomogeneity	18 40

TABLE 5 Characteristics of the principal components. Pretreatment: column autoscaling

Component	Eigenvalue	% Expl. variance	% Cumulative
1	22.164490	34.00766	34.008
2	11.814124	18.12677	52.134
3	6.688553	10.26245	62.397
4	4.160877	6.38416	68.781
5	3.437949	5.27495	74.056
6	2.993565	4.59312	78.649
7	2.422498	3.71691	82.366
8	2.101696	3.2247	85.591
9	1.982746	3.04219	88.633
10	1.144770	1.75646	90.389
11	0.988500	1.51669	91.906
12	0.799062	1.22603	93.132
13	0.622273	0.95477	94.087
14	0.582932	0.89441	94.981
15	0.486600	0.74661	95.728
16	0.436219	0.6693	96.397
17	0.364710	0.55959	96.957
18	0.316729	0.48597	97.443
19	0.299984	0.46027	97.903
20	0.211433	0.32441	98.227

FIGURE 5 Correlation tree among the variables, shown as dendrogram of the similarities (correlation coefficients) obtained by means of the single linkage method. The arrow indicates the group of much correlated variables.

FIGURE.6 Score plot on the two first principal components of all 66 variables (autoscaled). Red: Class1, Blue: Class 2, Green: Class 3, Magenta: Class 4. The convex hulls indicate the dispersion of the classes.

FIGURE 7 Score plot on the two first principal components of the 14 variables/features (autoscaled). Red: class 1, Blue: class 2, Green: class 3, Magenta: class 4.

FIGURE 8 Plots of the differences between scores of LDA. Red: class 1, Blue: class 2, Green: class 3, Magenta: class 4.

TABLE 6 Classification and prediction rates of KNN (K = 1), applied to all the autoscaled variables

Classification matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	19	1	0	0
Objects of class 2	2	17	1	0
Objects of class 3	1	0	18	1
Objects of class 4	1	1	1	17
	In class 1	In class 1	In class 1	In class 4
% correct classifications	95.00	85.00	90.00	85.00
% TOTAL	88.75
Prediction matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	74	5	1	0
Objects of class 2	12	63	4	1
Objects of class 3	4	0	66	10
Objects of class 4	4	4	8	64
	In class 1	In class 1	In class 1	In class 4
% correct predictions	92.50	78.75	82.50	80.00
% TOTAL	83.44

FIGURE 9 95% confidence ellipses computed with T² statistics in the space of the two first components.

TABLE 7 Classification and prediction rates of D-PLS (eight latent variables), applied to all the autoscaled variables

Classification matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	20	0	0	0
Objects of class 2	2	18	0	0
Objects of class 3	1	0	19	0
Objects of class 4	0	1	0	19
	In class 1	In class 1	In class 1	In class 4
% correct classifications	100.00	90.00	95.00	95.00
% TOTAL	95.00
Prediction matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	18	2	0	0
Objects of class 2	2	17	0	0
Objects of class 3	1	1	17	1
Objects of class 4	0	2	1	17
	In class 1	In class 1	In class 1	In class 4
% correct predictions	90.00	85.00	85.00	85.00
% TOTAL	86.25

TABLE 8 Classification and prediction rates of LDA applied to the four features selected by means of multivariate classification trees

Classification matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	100	0	0	0
Objects of class 2	10	85	5	0
Objects of class 3	5	0	95	082
Objects of class 4	0	5	13
	In class 1	In class 1	In class 1	In class 4
% correct classifications	100.00	85.00	95.00	82.00
% TOTAL	90.50
Prediction matrix
Order	Assigned to class 1	Assigned to class 2	Assigned to class 3	Assigned to class 4
Objects of class 1	20	0	0	0
Objects of class 2	2	17	1	0
Objects of class 3	1	0	19	0
Objects of class 4	0	1	3	16
	In class 1	In class 1	In class 1	In class 4
% correct predictions	100.00	85.00	95.00	80.00
% TOTAL	90.00