Depth-image-based Rendering 3D Images Research Articles

A bilateral attention based generative adversarial network for DIBR 3D image watermarking

This paper presents a bilateral attention based generative adversarial network (BAGAN) for depth-image-based rendering (DIBR) 3D image watermarking to protect the image copyright. Convolutional block operations are employed to extract main image features for robust watermarking, but embedding watermark into some features will degrade image quality much. To relieve this kind of image distortion, the bilateral attention module (BAM) is utilized by mining correlations of the center view and the depth map to compute attention of the 3D image for guiding watermark to distribute over different image regions. Since a modality gap exists between the center view and the depth map, a cross-modal feature fusion module (CMFFM) is designed for BAM to bridge the cross-view gap. Because the depth map has lots of flat background information including many redundant features, to prune them, the depth redundancy elimination module (DREM) is used for cross-view feature fusion. In the decoder, two extractors with the same structure are built to recover watermark from the center view and the synthesized view, respectively. In addition, the discriminator is supposed to build a competitive relationship with the encoder to increase the image quality. The noise sub-network is used to train different image attacks for robustness. Extensive experimental results have demonstrated that the proposed BAGAN can obtain higher watermarking invisibility and robustness compared with existing DIBR 3D watermarking methods. Ablation experiments have also proven the effectiveness of DREM, CMFFM and BAM on BAGAN.

A robust blind watermarking algorithm for depth-image-based rendering 3D images

The protection of 3D contents from illegal distribution has attracted considerable attention and depth-image-based rendering (DIBR) is proved to be a promising technology for 3D image and video displaying. In this paper, we propose a new digital watermarking scheme for DIBR 3D images based on feature regions and ridgelet transform (RT). In this scheme, the center view and the depth map are made available at the content provider side. After selecting the reference points of the center view, we construct the feature regions for watermark embedding. Considering the sparse image representation and directional sensitivity of the RT, the watermark bits are embedded into the amplitudes of the ridgelet coefficients of the most energetic direction. The virtual left and virtual right views are generated from the watermarked center view and the associated depth map at the content consumer side. The watermarked view has good perceptual quality under both the objective and subjective image quality evaluations. The embedded watermark can be detected blindly with low bit error rate (BER) from the watermarked center view, the synthesized left and right views even when the views are distorted and distributed separately. The experimental results demonstrate that the proposed scheme exhibits good performance in terms of robustness against various image processing attacks. Meanwhile, our method can be robust to common DIBR processing, such as depth image variation, baseline distance adjustment and different rendering conditions. Furthermore, compared with other related and state-of-the-art methods, the proposed algorithm shows higher accuracy in watermark extraction.

NSCT-Based Robust and Perceptual Watermarking for DIBR 3D Images

Depth-image-based rendering (DIBR), where arbitrary views are synthesized from a center image and depth image, has received much attention in the three-dimensional (3D) research field. With advances in depth-acquisition techniques and the proliferation of 3D glasses and 3D display devices, there is a growing demand for schemes to protect the copyrights of DIBR 3D images. Digital watermarking is a typical protection technology and designing a watermarking method for DIBR 3D images is a challenging task because the synchronization of watermarks can easily be broken in the process of generating synthetic images. To address this issue, we propose a non-subsampled contourlet transform (NSCT)-based blind watermarking for DIBR 3D images. To ensure the proposed method has properties of robustness against the DIBR process, we conduct an analysis of robustness for NSCT subbands against DIBR attacks. Based on the analysis results, we select subbands that are robust against DIBR attacks and embed watermark in the low coefficients of NSCT subbands using quantization-based embedding. While ensuring robustness, the proposed method also improves the imperceptibility of watermarks by adjusting their embedding strength according to computed perceptual masking values. Through experiments, we show that the proposed method is robust against both desynchronization attacks of the DIBR process and common attacks including signal processing operations and geometric distortions. The high imperceptibility of our method is also verified by several evaluation metrics in a subjective and objective manner.

Quality evaluation of DIBR 3D images based on blind watermarking

The quality evaluation of stereoscopic images is becoming increasingly important in 3D multimedia applications. Watermarking-based quality evaluation has been a promising technology for 3D content quality evaluation. In this work, we propose a novel quality evaluation scheme for depth-image-based rendering (DIBR) 3D images. The scheme utilizes the watermarking technique to evaluate the quality of watermarked images under various distortions. In this scheme, the watermark is embedded into the selected coefficients of dual-tree complex wavelet transform sub-bands of the center view. The virtual left and right views are synthesized from the watermarked center view and the associated depth map using the DIBR technique at the receiver side. The watermark can be detected from the three views individually, and the quality of these views under various attacks can be estimated by examining the degradation of corresponding extracted watermarks. In addition, the quality evaluation is made possible by checking the generated mapping curve, which maps the normalized correlation of the extracted watermark to the quality measure of the watermarked image under distortions. There is a high correlation between the estimated quality and the calculated quality. The experimental results demonstrate that the proposed scheme has good performance of quality evaluation for DIBR 3D images under JPEG compression, JPEG 2000 compression, Gaussian noise, and Gaussian blur. Moreover, our proposed scheme exhibits superiority over other related methods in terms of evaluation accuracy.

A Novel DIBR 3D Image Watermarking Algorithm Resist to Geometrical Attacks

A histogram shape based method is utilized to design watermarking algorithm to protect the Depthimage-based rendering (DIBR) 3D images. To make the watermarking method robust to common attacks, much more suitable pixel groups are selected for watermark embedding which are insensitive to geometric attacks. Taking into account the adjusting of baseline distance in DIBR process might affect the watermarking extraction, a postprocessing is proposed after DIBR process to make the proposed watermarking method much more robust to DIBR process. As the experimental results shown, the proposed method is much more robust to the geometric attacks and combined attacks compared with existing methods. In addition, the proposed watermarking method also has good robustness to the adjusting of baseline distance and depth image blurred.

A SIFT features based blind watermarking for DIBR 3D images

Depth image based rendering (DIBR) is a promising technique for extending viewpoints with a monoscopic center image and its associated per-pixel depth map. With its numerous advantages including low-cost bandwidth, 2D-to-3D compatibility and adjustment of depth condition, DIBR has received much attention in the 3D research community. In the case of a DIBR-based broadcasting system, a malicious adversary can illegally distribute both a center view and synthesized virtual views as 2D and 3D content, respectively. To deal with the issue of copyright protection for DIBR 3D Images, we propose a scale invariant feature transform (SIFT) features based blind watermarking algorithm. To design the proposed method robust against synchronization attacks from DIBR operation, we exploited the parameters of the SIFT features: the location, scale and orientation. Because the DIBR operation is a type of translation transform, the proposed method uses high similarity between the SIFT parameters extracted from a synthesized virtual view and center view images. To enhance the capacity and security, we propose an orientation of keypoints based watermark pattern selection method. In addition, we use the spread spectrum technique for watermark embedding and perceptual masking taking into consideration the imperceptibility. Finally, the effectiveness of the presented method was experimentally verified by comparing with other previous schemes. The experimental results show that the proposed method is robust against synchronization attacks from DIBR operation. Furthermore, the proposed method is robust against signal distortions and typical attacks from geometric distortions such as translation and cropping.

Robust contourlet-based blind watermarking for depth-image-based rendering 3D images

The copyright protection for 3D multimedia has attracted considerable attention and depth-image-based rendering (DIBR) has been playing a critical role in 3D content representation due to its numerous advantages. In this paper, we propose a new blind watermarking scheme for DIBR 3D images. Considering the directional multiresolution image representation and convenient tree structures of contourlet transform (CT), we perform the watermark embedding and extraction in contourlet domain. The center view and the depth map are available at the content provider side. After applying contourlet transform to the center view, we embed the watermark into the selected contourlet subbands of the center view by quantization on certain contourlet coefficients. The virtual left and right views are generated from the watermarked center view and the associated depth map using DIBR technique at the receiver side. The statistical differences between quantized and unquantized contourlet coefficients are used for watermark extraction. The watermark can be detected with a low bit error rate (BER) from the center view, the left and right views even when each view is distorted and distributed separately. The simulation results demonstrate that the proposed scheme is very robust to image compression, noise addition and geometric attacks such as rotation, scaling and cropping. Moreover, the proposed scheme has good performance in terms of depth image variation and baseline distance adjustment.

A robust DIBR 3D image watermarking algorithm based on histogram shape

Abstract Depth-image-based rendering (DIBR) has become an important technology in 3D displaying. Since either of the center image and generated virtual images might be illegally distributed, we need to protect both of the two kinds of images. In this paper, a histogram shape based watermarking algorithm is proposed to protect the DIBR 3D images. To make the watermarking method robust to common attacks, a pixel mean value based pixel groups selection method is presented to select several suitable pixel groups for watermark embedding. To solve the problem that the dividing of pixel groups can affect the performance of watermark extraction, the width of pixel group is determined by the maximum difference of pixel mean value between the original and attacked images. By this way, the watermark can be extracted with lower bit error rate (BER) from the attacked watermarked image. As the experimental results shown, the proposed method is much more robust to the geometric attacks and combined attacks compared with existing methods. In addition, the proposed watermarking method also has good robustness to the adjusting of baseline distance and depth image blurred.

A novel hashing scheme for Depth-image-based-rendering 3D images

Image hashing as an advanced approach has been widely applied in many areas such as image authentication, and content-based identification and retrieval. Being different from the traditional 2D image hashing scheme, virtual images which are generated in the DIBR process should be considered with the same content as the center image in Depth-image-based rendering (DIBR) 3D image hashing scheme. In this paper, we propose a hashing method for DIBR 3D images by applying three-level Dual-tree complex wavelet transform (DT-CWT) to images and selecting suitable DT-CWT coefficients to form the final hash sequence. Experimental results indicate that the proposed method is robust to a wide range of distortions and attacks. When compared with the current state-of-the-art methods, the proposed method can achieve better identification performances in terms of geometric attacks such as rotation attacks, whilst providing comparable performances under classical distortions such as additive noise, blurring, and compression. Furthermore, the proposed method is also able to ensure that the generated virtual images could be identified with the same content as the corresponding center image due to the characteristic approximate shift invariance of DT-CWT.

A novel watermarking for DIBR 3D images with geometric rectification based on feature points

Depth-image-based rendering (DIBR) has become an important technology in 3D displaying with its great advantages. As a result, more and more 3D products copyright problems turn out. Since either the center view with depth image or the synthesized virtual views could be illegally distributed, we need to protect not only the center views but also the synthesized virtual views. In this paper, a robust watermarking method for DIBR 3D images is proposed. After applying three-level DWT to the center image, we utilize spread spectrum technology to embed the watermark into suitable coefficients of the sub-blocks of the center image, by this way we make our method robust to typical signal distortions, such as JPEG compression, noise addition and median filter. Meanwhile, in order to make the proposed method robust to some common geometric distortion attacks, SIFT-based feature points are used for geometric rectification to eliminate the effect caused by geometric distortion attacks. As the experimental results shown, the proposed method is much more robust to the common signal distortion attacks with lower BER (bit error rate) compared with existing methods. With geometric rectification, our method also performs good robustness to some simple affine transformations. In addition, the proposed watermarking method also has good robustness to the common operations of DIBR processing system.

Watermarking for DIBR 3D images based on SIFT feature points

With number of advantages, depth-image-based rendering (DIBR) has became an important technology in 3D displaying, as result, more and more copyright problems will turn out. Since either the center view with depth image or the synthesized virtual views could be illegally distributed, we need to not only protect the center views but also the synthesized virtual views with a novel method. In this paper, a novel watermarking method for DIBR 3D images is proposed, by using SIFT to select the area where watermarking should be embedded, we can utilize Spread spectrum technology to embed the watermark information into the DCT coefficients of the selected area. As the experimental results shown, the proposed method is much more robust to some common signal distortion attacks with lower BER compared with existing methods.

Robust DT-CWT Watermarking for DIBR 3D Images

The popularity of 3D content is on the rise since it provides an immersive experience to viewers. In this situation, depth-image-based rendering (DIBR) has taken on an important role in 3D technology due to its low bandwidth cost and ease of depth configuration. Noting that the viewer could record provided center view or synthesized views for illegal distribution, it is clear that copyright protection must be taken into account for the DIBR 3D content, including the possibility that one single view could be illegally distributed as 2D content. In this paper, we propose a robust watermarking scheme for DIBR 3D images by quantization on dual-tree complex wavelet transform (DT-CWT) coefficients with consideration of imperceptibility. To make the proposed scheme robust to DIBR process, two characteristics of DT-CWT are employed: approximate shift invariance and directional selectivity. We select certain coefficient sub-blocks and group the coefficient rows based on the properties of DIBR. On the extraction side, the threshold is carefully chosen with a low false positive rate. The simulation results show that the embedded watermark is stably extracted from the center view and the synthesized left and right views. In addition, even if the synthesized left and right views are distorted by general attacks, the watermark is successfully extracted. Furthermore, the proposed scheme is robust to pre-processing of the depth image and baseline adjusting, which are common processing on the DIBR system for better quality of 3D views.

A Digital Blind Watermarking for Depth-Image-Based Rendering 3D Images

The content protection for image-based 3D data is getting more importance with the advance of low cost 3D display devices. The depth-image-based rendering (DIBR) 3D image is one of the image-based 3D data which consists of the center image and the depth image generated by the content provider. The left-eye image and the right-eye image are rendered from the center image and the depth image at the content consumer side. The blind watermarking for DIBR 3D image is rarely studied in the literature. In this paper, a novel blind multiple watermarking scheme is proposed to deal with the content protection problem of DIBR 3D images. Besides the usual requirement of mutual orthogonality among reference patterns for multiple watermark embedding, we found that proper embedding order plays an even more important role in watermarking the DIBR 3D images. Experimental results show that the proposed scheme is robust against the JPEG compression and noise adding attacks. More interestingly, it is found that the proposed watermarking can also tolerate large range variations of the depth image during rendering.