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A content based digital image signature scheme for image authentication is proposed. The signature is implemented by image watermarking in the wavelet domain. We introduce interdependency between the watermark and the image data sequence, so that the detection and verification of the signature are independent of the original image and the knowledge of the original watermark sequence or location are...
Improvements of embedded zero-tree wavelet (EZW) coding by employment of soft-thresholding in the wavelet domain are reported. By proper adjustment of the thresholds, the attainable PSNR can be slightly improved (around 0.3 dB). Moreover, soft-thresholding can improve the visual appearance of the coded images, especially in the very low data rate case. The quality in the early stages of progressive...
This contribution is about the design of an image compression scheme for near loss-less image compression of a restricted class of images and a specific application. The images are digital diagnostic X-ray images of the coronary vessels of the human heart. This paper proposes a novel compression scheme with a compression ratio of 8–10 with preservation of the diagnostic image quality. Central in our...
This paper proposes a noise reduction method for screen content coding using HEVC. The proposed method focuses on that the histograms of pixel values for screen content have distinct and sparse peaks respectively. This property is often degraded by the coding distortion, which arises some small peaks around the original peak. This paper presents a method for removing the small peaks derived from the...
In this paper, we propose a noise reduced tone mapping method based on information content weights, where the perceptually unimportant pixels are smoothed during the decomposition in two steps. First, a saliency-based information content weight is introduced to give high fidelity to the data term based on the ratio of the local pixel power and the overall noise power in the base layer decomposition...
In this paper, we propose a new perceptual model for balanced multiwavelet (BMW) transforms. The latter transform achieves simultaneous orthogonality and symmetry without requiring any input prefiltering. The proposed model is derived using multiresolution domain extensions of Chou's model. The proposed model depends only on the image activity and not the multifilter sets used by the transform, unlike...
In this paper, a new image compression method is presented using the Distance Transform on Curved Space (DTOCS) and derivative information in finding positions for control points. In previous work it has been shown that the control points are not in exactly optimal positions. This paper presents theoretical considerations according to which the new method enhances the decompressed image quality particularly...
It is known that the performance of the Discrete Wavelet Transform (DWT) decreases when attempting to compress noisy images, and that it can be improved if a suitable denoising algorithm is used as a preprocessing stage. In this paper we show that this cannot be straightforwardly applied to the Integer Wavelet Transform (IWT) due to the non-linear operations involved. We propose an algorithm based...
In this work we address the problem of document image compression, which has recently received increasing attention in the literature. To guarantee a high compression ratio and a satisfactory visual quality, the problem at hand requires sophisticated compression techniques, together with careful image preprocessing to remove noise, paper degradation artifacts, and ghost images from the back page....
Steganography is an authenticated technique for maintaining secrecy of embedded data. The novel concept of replacing mantissa part of cover image by the generated mantissa part of payload is proposed for higher capacity and security. The Lifting wavelet Transform (LWT) is applied on both cover image and payload of sizes a * a and 3a * 2a respectively. The mantissa values of Vertical band (CV), Horizontal...
Contrast and brightness of digital images can be adjusted by contrast enhancement. Mostly digital images are stored in Jpeg format in real application like Internet and Mobile phones. In order to reduce the size digital images are compressed with high, middle and low quality factor. Move and paste type of images are created by malicious person, in which contrast of one source image is enhanced to...
Pre-processing and post-processing algorithms improve on the performance of a video compression system especially by removing spurious noise and insignificant features from the original video data. So that this will increases compression efficiency, attenuates coding artifacts and mainly improving the quality of Video data. And more over existing video compression standards like MPEG, H.26x series...
With the growing awareness of the fraud case for digital images, the researchers have developed some forensic techniques that based on the intrinsic statistical history or trace left by the JPEG compression to determine an image's manipulation. In this letter, we present an improved counter-forensic scheme that based on parameter adjustment. The simulation shows that by using the proposed strategy...
Watermarking in wavelet domain and with SVD is popular due to its robustness. In this paper a watermarking technique using DCT wavelet and hybrid DKT-DCT wavelet along with SVD is proposed. Wavelet transform is applied on host and SVD is applied on watermark. Few singular values of watermark are embedded in mid frequency band of host. Scaling of singular values is adaptively done for each channel...
In this paper, we propose a new reversible watermarking of medical images for the applications in telemedicine. By using a bit-stream insertion scheme, the patient's information can be treated as a watermark and can be embedded into the bit-stream of a cover image for remote transmission. The proposed method simplifies the design of traditional image coding after a reversible watermarking. Experimental...
Micro lens captures less light than normal lens dose, which makes low quality noise image, and current image sensor cannot preserve whole dynamic range in real world. HDR image with multi-exposure image overcomes the problems mentioned above. Choosing good exposure time is a seldom-discussed but important issue in HDR imaging technology. In this paper we propose a Histogram Based Exposure Time Selection...
The detection of JPEG prior compression has become an essential task in the detection of forgery in image forensics. In this paper we propose a novel DCT implementation technique that can be utilized in the detection of any hacking or tampering of JPEG/DCT compressed images. The proposed approach is based upon recent literature ideas of recompressing JPEG image blocks and detecting if this block has...
Compared to HD (high definition), UHD (ultra-high definition) video provides higher visual quality. However, artefacts in UHD content are more apparent due to increased spatial resolution. False contouring is one of the visual artefacts in compressed UHD video sequences which affect the visual experience. This paper proposes a dithering method to remove the visual contouring while keeping artefact-free...
This paper presents a robust watermarking for still digital images based on Fast Walsh-Hadamard Transform (FWHT) and Singular Value Decomposition (SVD) using Zigzag scanning. In this paper, after applying Fast Walsh-Hadamard transform to the whole cover image, the Walsh-Hadamard coefficients are arranged in zigzag order and mapped into four quadrants-Q1, Q2, Q3, Q4. These four quadrants represent...
Visual cryptography is one of the emerging technology which has been used for sending secret images in highly secure manner without performing the complex operations while encoding. This technology can be used in the many fields like transferring military data, financial scan documents, sensitive image data and so on. In the literature different methods are used for black and white image which produce...
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