Efficient Collusion Attack-Free Access Control for JPEG 2000 Coded Images

This paper proposes an efficient access control method for JPEG 2000 coded images with multiple dimensions of hierarchical scalability. An access control method is required to 1) be resilient to collusion attack and 2) manages less number keys from the perspective of the key management cost. The proposed method is resilient to collusion attack and manages only one key. Moreover, the proposed method reduces the length of managed key in comparison with the conventional methods satisfying above two requirements. This feature serves an efficient key management.APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference. 4-7 October 2009. Sapporo, Japan. Poster session: Image, Video, and Multimedia Signal Processing 1 (5 October 2009)

Reversible Image Processing for Color Images with Flexible Control

In this paper, we propose an image processing method for color images to reversibly achieve flexible functions. Most previous research has focused on reversible contrast enhancement (CE) for grayscale images. When we directly apply these methods to color images, hue distortion is caused. Several previous methods have been proposed for color images. These methods, however, only have a CE function. We previously proposed a reversible method for color images that enhances the brightness contrast and improves the saturation. Without losing the advantages of our previous method, we propose a new method to expand the ability of image processing. The proposed method reversibly achieves not only CE and saturation improvement but also sharpening or smoothing and brightness increases or decreases. It ensures full reversibility and thus perfectly reconstructs raw images in any case. The experimental results demonstrate the effectiveness of the proposed method in terms of image quality and reversibility

High-Capacity Reversible Data Hiding in Encrypted Images with Flexible Restoration

In this paper, we propose a novel reversible data hiding in encrypted images (RDH-EI) method that achieves the highest hiding capacity in the RDH-EI research field and full flexibility in the processing order without restrictions. In the previous work in this field, there exist two representative methods; one provides flexible processing with a high hiding capacity of 2.17 bpp, and the other achieves the highest hiding capacity of 2.46 bpp by using the BOWS-2 dataset. The latter method has critical restrictions on the processing order. We focus on the advantage of the former method and introduce two efficient algorithms for maximizing the hiding capacity. With these algorithms, the proposed method can predict each pixel value with higher accuracy and refine the embedding algorithm. Consequently, the hiding capacity is effectively enhanced to 2.50 bpp using the BOWS-2 dataset, and a series of processes can be freely conducted without considering any restrictions on the order between data hiding and encryption. In the same way, there are no restrictions on the processing order in the restoration process. Thus, the proposed method provides flexibility in the privileges requested by users. Experimental results show the effectiveness of the proposed method in terms of hiding capacity and marked-image quality

An Extension of Reversible Image Enhancement Processing for Saturation and Brightness Contrast

This paper proposes a reversible image processing method for color images that can independently improve saturation and enhance brightness contrast. Image processing techniques have been popularly used to obtain desired images. The existing techniques generally do not consider reversibility. Recently, many reversible image processing methods have been widely researched. Most of the previous studies have investigated reversible contrast enhancement for grayscale images based on data hiding techniques. When these techniques are simply applied to color images, hue distortion occurs. Several efficient methods have been studied for color images, but they could not guarantee complete reversibility. We previously proposed a new method that reversibly controls not only the brightness contrast, but also saturation. However, this method cannot fully control them independently. To tackle this issue, we extend our previous work without losing its advantages. The proposed method uses the HSV cone model, while our previous method uses the HSV cylinder model. The experimental results demonstrate that our method flexibly controls saturation and brightness contrast reversibly and independently