High Capacity Image Steganography Using Modified LSB Substitution and PVD against Pixel Difference Histogram Analysis

Abstract

The combination of pixel value differencing (PVD) and least significant bit (LSB) substitution gives higher capacity and lesser distortion. However, there are three issues to be taken into account: (i) fall off boundary problem (FOBP), (ii) pixel difference histogram (PDH) analysis, and (iii) RS analysis. This paper proposes a steganography technique in two variants using combination of modified LSB substitution and PVD by taking care of these three issues. The first variant operates on 2 × 3 pixel blocks and the second technique operates on 3 × 3 pixel blocks. In one of the pixels of a block, embedding is performed using modified LSB substitution. Based on the new value of this pixel, difference values with other neighboring pixels are calculated. Using these differences, PVD approach is applied. The edges in multiple directions are exploited, so PDH analysis cannot detect this steganography. The LSB substitution is performed in only one pixel of the block, so RS analysis also cannot detect this steganography. To address the FOBP, suitable equations are used during embedding procedure. The experimental results such as bit rate and distortion measure are satisfactory.

Digital Image Steganography Using Eight-Directional PVD against RS Analysis and PDH Analysis

“…On the other hand the PSNR of type 1 is better than that of type 2. Table 6 represents the comparison of the proposed technique with the adaptive PVD technique in [26] and hybrid techniques in [27,28]. The comparison parameters are average PSNR and average hiding capacity values.…”

“…The hiding capacity of proposed technique is greater than all the four variants of the hybrid technique proposed in [27]. The technique in [28] uses PVD with modified LSB (MLSB) substitution. The results of this technique (type 1) are as good as the results of 8 Advances in Multimedia Table 5: Results of proposed eight-directional PVD technique.…”

“…Proposed, type 1 (t=3, Range Table 1) Proposed, type 2 (t=4, Range Table 6: Comparison of the proposed technique with techniques in [26][27][28].…”

“…Seven lakhs (700,000) bits 3 PVD +3 LSB +EMD, type 2 [27] 38.95 1798834 7 PVD +3 LSB +EMD, type 1 [27] 40.28 1710888 7 PVD +3 LSB +EMD, type 2 [27] 37.26 1823282 Proposed eight-directional PVD, type 1 39.55 2361368 Seven lakhs (700,000) bits Proposed eight-directional PVD, type 2 37.22 2603604 Five-directional PVD+MLSB, type 1 [28] 37.62 2399853…”

“…Eight lakhs and forty thousand (840,000) bits Five-directional PVD+MLSB, type 2 [28] 36.23 2514038 Eight-directional PVD+MLSB, type 1 [28] 37.49 2394086 Eight-directional PVD+MLSB, type 2 [28] 35.60 2603604 the proposed technique (type 1). Similarly, the results of this technique (type 2) are as good as the results of the proposed technique (type 2).…”