Tunnel Lining Crack Recognition Based on Improved Multiscale Retinex and Sobel Edge Detection

Table 2

Objective quality evaluation of each algorithm.

Algorithm	PSNR	Entropy	Contrast
Original image	91.49	4.19	59.15
SSR	94.56	4.93	89.11
MSR	95.38	4.95	86.85
MSR-B algorithm	105.30	5.32	126.42