Acquisition of a single grid-based phase-contrast X-ray image using instantaneous frequency and noise filtering

Table 1 Peak signal-to-noise ratio (PSNR), mean squared error (MSE), and structural similarity index map (SSIM) values for the reference and comparison images

Image quality	Reference:	RT4 (5X) Bottom row, 5st column image
	Comparison:	RT4 (5X)					RT2 (5X)
		1st column image	2st	3st	4st	5st
PSNR value (dB)	Top row	12.42	19.89	20.1	17.52	16.15	10.04
	Middle row	12.95	15.25	17.8	20.42	22.74
	Bottom row	14.71	18.91	22.7	27.54 ¹
MSE value	Top row	0.011	0.0047	0.0046	0.0062	0.0072	0.015
	Middle row	0.01	0.008	0.006	0.0044	0.0034
	Bottom row	0.0085	0.0052	0.0034	0.0019 ¹
SSIM value	Top row	0.86	0.95	0.96	0.92	0.89	0.79
	Middle row	0.87	0.91	0.94	0.96	0.98
	Bottom row	0.91	0.96	0.98	0.99 ¹

Reference image: bottom row, fifth column of RT4. Comparison image: the 14 images of RT4 excluding the reference image and the one image of RT2 in Fig. 8. RT: rectangle

ISSN: 1475-925X