Contourlet transform has been proved superior to wavelet in representation piecewise texture and contour characters in digital images. In order to improve the retrieval rate further, we studied the representation abilities of some different filters for texture features in two contourlet retrieval systems. The two systems both used Canberra distance for similarity measure, but different feature ...

For image compression purposes a general framework for modification of transform coefficients is proposed in this paper. To show the functionality of the method, we applied it to the contourlet transform. Unlike non-linear approximation (NLA) algorithms, the proposed algorithm causes the modification of the coefficients to be performed in a controlled manner. Different coefficients in different...

Face recognition is a process of identifying people from their face images. Face recognition technology has many applications such as ATM access, verification of credit card, video surveillance etc. In this paper, we propose a novel face recognition algorithm which exploits both local and global features for feature extraction. Local features are extracted by Gabor wavelets and for global featu...

A new image fusion algorithm of the multispectral image and the panchromatic image is proposed by using the non-subsampled contourlet transform and the lαβ color space. The non-subsampled contourlet transform is used to decompose an image into a low frequency approximate component and several high frequency detail components, and an edge enhancement method is employed to extract features from a...

Speckle noise affects all coherent imaging systems including medical ultrasound. In medical images, noise suppression is a particularly delicate and difficult task. A tradeoff between noise reduction and the preservation of actual image features has to be made in a way that enhances the diagnostically relevant image content. Even though wavelets have been extensively used for denoising speckle ...

we propose a robust quantization-based image watermarking scheme, called the gradient direction watermarking (GDWM), and based on the uniform quantization of the direction of gradient vectors. In GDWM, the watermark bits are embedded by quantizing the angles of significant gradient vectors at multiple wavelet scales. The proposed scheme has the following advantages: 1) Increased invisibility of...

To improve the recognition rate in different conditions, a multiscale face recognition method based on nonsubsampled contourlet transform and support vector machine is proposed in this paper. Firstly, all face images are decomposed by using nonsubsampled contourlet transform. The contourlet coefficients of low frequency and high frequency in different scales and various angles will be obtained....