PENGARUH PENERAPAN POINT OPERATION IMAGE ENHANCEMENT PADA CITRA PENAMPUNG TERHADAP KAPASITAS PESAN PADA STEGANOGRAFI DCT SEKUENSIAL DAN STEGANOGRAFI DCT F5; EFFECT OF POINT OPERATION IMAGE ENHANCEMENT ON MESSAGE CAPACITY AT COVER IMAGE BETWEEN DCT SEQUENTIAL AND DCT F5 STEGANOGRAPHIC ALGORITHM

DIAN HAFIDH ZULFIKAR, Agus Harjoko

2015 | Disertasi | FMIPA

Steganography in the transform domain involves the manipulation of algorithms and image transforms. JPEG images is one steganography in the domain Discrete Cosine Transform (DCT). Some of the criterias of good steganography surely must have optimal capacity, good quality and good durability ( Robust). Besides the algorithm itself, the cover image is one of the things that are important in determining of steganography. Steganographic process in DCT domain is generally performed on the value of DCT quantization process results which has a value other than 0, of course, is related to the distribution of the diversity of pixels in the image. In this study will apply some point operation of image enhancement techniques (POIE) like histogram equalization, contrast stretching, brigthening and gamma correction to the cover image on DCT sequential and DCT F5 steganographic method to determine differences in message capacity, quality and robustness of stego image. The parameter used is the number of bits that can be accommodated message, PSNR and MSE value, and the value of DCT coefficient quantization results. Based on test results have got several conclusions that message capacity on DCT sequential greater than the DCT F5 steganographic method either before or after POIE, stego image quality on DCT F5 better than the DCT sequential steganographic method well before and after POIE, both DCT F5 and DCT sequential steganographic method equally resistant to manipulated on stego image.

Kata Kunci : Steganographic; domain DCT; cover image; message capacity, image quality; point operation image enhancement; DCT sequential; DCT F5.