This paper presents two JPEG steganographic methods using quantization index modulation (QIM) in the discrete cosine transform (DCT) domain. The two methods approximately preserve the histogram of quantized DCT coefficients, aiming at secure JPEG steganography against histogram-based attacks. In comparison with F5 as a representative JPEG steganography, the proposed methods show high performanc...

This brief proposes an efficient prime factor algorithm for the discrete cosine transform. In the proposal, we formulate the decomposition directly, by using the proposed input and output mapping, a novel in-place address generation scheme for input index mapping is derived, while the formulations in the literature require a table to store the index mapping. Besides, our approach requires one o...

Colliding Bodies Optimization (CBO) is a population-based metaheuristic algorithm that complies physics laws of momentum and energy. Due to the stagnation susceptibility of CBO by premature convergence and falling into local optima, some meritorious methodologies based on Sine Cosine Algorithm and a mutation operator were considered to mitigate the shortcomings mentioned earlier. Sine Cosine Al...

The recognition of human faces, especially those with different orientations is a challenging and important problem in image analysis and classification. This paper proposes an effective scheme for rotation invariant face recognition using Log-Polar Transform and Discrete Cosine Transform combined features. The rotation invariant feature extraction for a given face image involves applying the l...

introduction: filtering can greatly affect the quality of clinical images. determining the best filter and the proper degree of smoothing can help to ensure the most accurate diagnosis. methods: forty five patient’s data aquired during brain phantom spect studies were reconstructed using filtered back-projection technique. the ramp, shepp-logan, cosine, hamming, hanning, butterworth, metz and w...

Motivated by the fact that in textures, there is usually a presence of strongly oriented harmonics, a representation which is both well-localised in frequency and orientation is desirable to efficiently describe such oriented harmonic features. Here we introduce a family of directional trigonometric bases for a bi-variate function which is defined as !#"%$ & '( )$+* ,-&% .% /.% where the 0 is a...