Author Affiliations
1College of Science, National University of Defense Technology, Changsha 410073, China2Xi’an Satellite Control Center, Xi’an 710043, China3Tiansun Laboratory, Changsha 410073, China4School of Computer Science and Technology, Xidian University, Xi’an 710071, China5College of Electronic Science, National University of Defense Technology, Changsha 410073, China6Hunan Institute of Traffic Engineering, Hengyang 421099, Chinashow less
Fig. 1. (a) Experimental schematic of non-iris SSCI system. RD, rotating diffuser; u, 35–50 cm; v, 15 cm; (b) flow chart of the proposed method.
Fig. 2. Experiment results of non-iris SSCI at a scale factor of 0.3. (a1)–(a4) Raw speckle images of different objects; (b1)–(b4) resized speckle images of (a1)–(a4); (c1)–(c4) autocorrelations of (b1)–(b4); (d1)–(d4) images reconstructed from (c1)–(c4) through phase-retrieval algorithm; (e1)–(e4) corresponding original objects. Scale bars, 1 mm.
Fig. 3. Logarithmic speckle autocorrelation and the normalized power spectrum at different scale factors s. (a1) Autocorrelation of the original object, i.e., the ideal autocorrelation; (b1) power spectrum generated from (a1); (a2)–(a5) speckle autocorrelations at different scale factors 0.1, 0.4, 0.7, and 1; (b2)–(b5) power spectrum from (a2)–(a5), respectively; (c1)–(c5) corresponding reconstructed results for (b1)–(b5) through Ping-pong algorithm; (d) normalized frequency spectra of the center rows of (b1)–(b5) (positive frequencies are shown); (e) quantitative evaluation of speckle autocorrelations using PSNR at different scale factors. Scale bars, 1 mm.
Fig. 4. Experimental results with another two cameras and new parameters. (a1)–(a4) Autocorrelations of the resized image by the factor of s at different distances v; (b1)–(b4) images reconstructed from (a1)–(a4) through phase-retrieval algorithm; (c1)–(c4), (d1)–(d4) as in (a1)–(a4), (b1)–(b4) but for different cameras and s. Scale bars, 1 mm.
Fig. 5. Comparison of experimental results by digital resizing and pixel binning. (a1)–(a3) Raw speckle images of symbol “5” at different distances v: (a1)v = 10 cm; (a2) v = 15 cm; (a3) v = 20 cm; (b1)–(b3) resized speckle images (central part is shown) of (a1)–(a3) by different s (0.5, 0.3, 0.25); (c1)–(c3) objects reconstructed from (b1)–(b3) through phase-retrieval algorithm; (d1)–(d3) binned (2 × 2, 3 × 3, 4 × 4) speckle images at the same distance v as in (a1)–(a3); (e1)–(e3) objects reconstructed from (d1)–(d3) through phase-retrieval algorithm. Scale bars, 1 mm.