Depth Detection of Material Surface Defects Based on Laser Thermography

Defect depth /mm	Gray value	Temperature /K
0.13	124	320.20
0.26	119	317.60
0.39	117	316.50
0.52	112	313.70
0.65	110	312.60
0.78	109	312.00
0.91	108	311.40
1.04	108	311.40
1.17	106	310.30
1.30	105	309.65
1.43	103	308.50
1.56	100	306.70
1.69	98	305.05
1.82	98	305.05
1.95	96	304.50
2.08	90	300.85
2.21	89	299.85
2.34	87	298.50
2.47	83	295.83

Table 2. Parameters of fitting equations
View table
Table 2. Parameters of fitting equations
Fitting curve Fitting equation SSE RMSE
Exponential equation T_B=345-26.28exp(0.25d_depth) 19.79 1.112
Linear equation T_B=320.1-8.97d_depth 23.74 1.18
Quadratic equation T_B =-0.93d_{depth 2}-6.56d_depth +319 20.42 1.13

Table 3. Residuals between fitting equation and measured data
View table
Table 3. Residuals between fitting equation and measured data
Defect depth /mm 0.13 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.17 1.30
‖e‖ 0.22 0.21 0.13 0.20 0.24 0.19 0.14 0.01 0.03 0.02
Defect depth /mm 1.43 1.56 1.69 1.72 1.95 2.08 2.21 2.34 2.47
‖e‖ 0.01 0.04 0.04 0.08 0.09 0.10 0.02 0.01 0.05

Table 4. Parameters of fitting equations

View table

Table 4. Parameters of fitting equations

Various parameters of fitting curve when temperature of A is 320.15 K
Fitting curve		Fitting equation		SSE		RMSE
Exponential equation		T_B=321.7-3.81exp(0.51d_depth)		4.53		0.53
Linear equation		T_B=318.9-3.88d_depth		7.94		0.68
Quadratic equation		T_B =-0.89d_{depth 2}-1.56d_depth +317.9		4.85		0.55
Various parameters of fitting curve when temperature of A is 317.15 K
Fitting curve		Fitting equation		SSE		RMSE
Exponential equation		T_B=321.8-6.45exp(0.33d_depth)		4.25		0.51
Linear equation		T_B=316-3.29d_depth		5.61		0.57
Quadratic equation		T_B =-0.58d_{depth 2}-1.77d_depth +315.3		4.27		0.52
Various parameters of fitting curvewhen temperature of A is 314.15 K
Fitting curve	Fitting equation		SSE		RMSE
Exponential equation	T_B=317-4.33exp(0.39d_depth)		3.96		0.49
Linear equation	T_B=313.3-2.91d_depth		4.21		0.50
Quadratic equation	T_B =-0.26d_{depth 2}-2.23d_depth+313		3.98		0.50

Tools

Get Citation

Copy Citation Text

Jiaqi Liu, Zhijie Zhang, Zhenyu Lin, Wuliang Yin. Depth Detection of Material Surface Defects Based on Laser Thermography[J]. Laser & Optoelectronics Progress, 2021, 58(4): 0411002

Download Citation

EndNote(RIS)BibTex Plain Text

Set citation alerts for article

Save article for my favorites