Improved payload capacity in LSB image steganography uses dilated hybrid edge detection

This research proposed the dilated hybrid edge detection on the three most significant bits (MSB) pixels of cover images with the aim of expanding the edge area so as to increase the data embedding capacity in image steganography. This technique can perform extraction without the need to save edge detection on the original cover image. This is because edge detection is performed on 3-bits MSB images, whereas messages are embedded at x LSB and y LSB values, where x is the number of LSB bits replaced in the edge area and y is the number of bits replaced in the non-edge area, where x and y cannot reach 3-bits MSB, so the edge detection of the cover image and the stego image will be the same. Based on the results of tests carried out, the proposed steganography technique succeeded in improving the quality of imperceptibility, where the PSNR value increased by about 1 to 2 dB when compared to the previous method. Similarly, the message embedding capacity can be increased due to a wider edge area, with the same image dataset obtained an average increase of 4,350–12,364 pixels of the edge area, however, the quality of the stego image imperceptibility can be maintained.