Atlas-based segmentation of neck muscles from MRI for the characterisation of Whiplash Associated Disorder

Whiplash-associated disorder (WAD) is a commonly occurring injury that often results from neck trauma suffered in car accidents. However the cause of the condition is still unknown and there is no definitive clinical test for the presence of the condition. Researchers have begun to analyze the size of neck muscles and the presence of fatty infiltrates to help understand WAD. However this analysis requires a high precision delineation of neck muscles which is very challenging due to a lack of distinctive features in neck magnetic resonance imaging (MRI). This paper presents a novel atlas-based neck muscle segmentation method which employs discrete cosine-based elastic registration with affine initialization. Our algorithm shows promising results based on clinical data with an average Dice similarity coefficient (DSC) of 0.84±0.0004

An Overview of Digital Video Watermarking

The illegal distribution of a digital movie is a common and significant threat to the film industry. With the advent of high-speed broadband Internet access, a pirated copy of a digital video can now be easily distributed to a global audience. A possible means of limiting this type of digital theft is digital video watermarking whereby additional information, called a watermark, is embedded in the host video. This watermark can be extracted at the decoder and used to determine whether the video content is watermarked. This paper presents a review of digital video watermarking techniques in which their applications, challenges and important properties are discussed, and categorizes them based on the domain in which they embed the watermark. It then provides an overview of a few emerging innovative solutions using watermarks. Protecting a 3D video by watermarking is an emerging area of research. The relevant 3D video watermarking techniques in the literature are classified based on the image-based representations of a 3D video in stereoscopic, depth-image-based rendering and multi-view video watermarking. We discuss each technique and then present a survey of the literature. Finally, we provide a summary of this study and propose some future research directions

Robust DT CWT Based DIBR 3D Video Watermarking using Chrominance Embedding

The popularity of 3D video is increasing daily due to the availability of low-cost 3D televisions and high-speed Internet access. However, currently the contents of 3D video can be distributed illegally without any protection. For views generated using a depth-image-based rendering technique, not only the left and right views can be distributed as 3D content, but also the center, left, or right views individually as 2D content. As digital video watermarking is a possible way of protecting these views from unauthorized distribution, in this paper, we propose a digital watermarking method for depth-image-based rendered 3D video. In this method, the watermark is embedded in both of the chrominance channels of a YUV representation of the center view using the dual-tree complex wavelet transform. Then, the left and right views are generated from the watermarked center view and depth map using a depth-image based rendering technique. Finally, the watermark can be extracted from the center, left, and right views in a blind fashion without using the original unwatermarked center, left, or right views. This watermark is robust to geometric distortions, such as upscaling, rotation and cropping, downscaling to an arbitrary resolution, and the most common video distortions, including lossy compression and additive noise. Due to the approximate shift invariance characteristic of the dual-tree complex wavelet transform, the technique is robust against distortions in the left and right views generated using depth-image based rendering. The proposed method can also survive baseline distance adjustment and both 2D and 3D camcording

3D-Mapping for Visualisation of Rigid Structures: A Review and Comparative Study

In this review, we discuss state-of-the-art developments in 3D models for small and rigid structures. This includes the pros and cons of cutting-edge range cameras used as active 3D scanners, while also considering passive image reconstruction schemes by means of the well-known structure-from-motion (SfM) algorithms. Furthermore, we discuss the issue of how data fusion algorithms can be used to optimally fuse 2D contour information onto 3D models for several different applications. Considering the benefits of 3D range sensors, we also review current trends in optimum data fusion of point clouds from 3D range sensors. We present the benefits and the limitations of each algorithm against various design considerations. To highlight the pros and cons, we also perform a comparative study of the performance of a 3D range sensor, represented by an iPad structure sensor, with respect to the well-known SfM software packages, namely, Bundler, Microsoft PhotoSynth, Agisoft PhotoScan, and Smart3DCapture. Last, we highlight several research opportunities and potential research challenges associated with each technique

Blind Video Watermarking for the Detection of Illegal Downloading of Video Content

Illegal distribution of a digital movie is a significant threat to the film industry. Currently, camcorder theft is the single largest source of video piracy and is one of the most significant problems facing movie studios and producers. Approximately ninety percent of the first versions available of illegally distributed new release films have been pirated using a digital camcording device in a movie theatre. With the advent of high-speed broadband Internet access, a pirated copy of a digital video can be easily distributed to a global audience for viewing online and downloading within just days of its release in theatres. Even though there are strict laws in many countries against video piracy, they have proven to be ineffective and it has not been possible to prevent this practice. Therefore, protecting the copyright of digital video content is becoming very important. As the popularity of 3D videos is increasing daily, concern over protecting them from unauthorised distribution is also growing.Digital video watermarking is a possible means of limiting this type of digital distribution. This is the process of embedding extra information in a host video signal so that the watermark is imperceptible and, in a blind detection system, it is robust and difficult to remove or alter. In existing watermarking methods, the watermark is usually embedded in the luminance (Y) channel in a YUV representation of a video frame which affects imperceptibility. In addition, none of the existing techniques are robust to the combination of commonly used attacks, including lossy compression, upscaling, rotation, cropping, downscaling in resolution, aspect ratio change, frame rate conversion and camcording. The key focus of this work is to design a digital video watermarking algorithm for both 2D and 3D content that can mitigate their associated challenges.In the first part of this dissertation, a blind digital video watermarking algorithm is proposed. The watermark is embedded in one level (low-frequency coefficients) of the dual-tree complex wavelet transform (DT CWT) of the chrominance (U) channel, and extracted using the same key and level used for embedding. This embedding in the U channel provides a high-quality watermarked video and the DT CWT enhances its robustness to geometric attacks, such as scaling, rotation and cropping, due to its approximate shift invariance characteristic. To evaluate the overall performance of the proposed method for H.264/AVC compression and geometric attacks, an experimental comparison of the proposed U channel embedding approach, Y channel embedding and two existing methods is undertaken. The experimental results verify the efficacy of the proposed algorithm.The downscaling in resolution of a frame in the spatial domain removes the high-frequency information. As a result, the watermark and low-frequency coefficients in the DT CWT domain spread into the new high-frequency coefficients. In such a situation, watermark detection results in a false negative error if it extracts from only the level used for embedding. Therefore, in the second part of this work, an extension of the first method extracts the watermark from any level(s) of the DT CWT decomposition depending on the resolution of the downscaled version of the watermarked frame. However, this method still suffers in terms of temporal synchronisation attacks, such as frame rate conversion, as the embedding key is required for detection. To overcome this limitation, the watermark of a frame is extracted from the information of that frame without using the key used during its embedding. The experimental results show that the proposed method is not only robust to temporal synchronisation attacks and downscaling to an arbitrary resolution but also upscaling, rotation, cropping, lossy compression, camcording, watermark estimation remodulation, temporal frame averaging and multiple watermark embedding.In the last part of this research, the emphasis is on protecting a depth-image based rendered (DIBR) 3D video. The proposed scheme embeds the watermark in both the chrominance channels (U and V) of the centre view using the DT~CWT. Then, the synthesised watermarked stereo pairs (left and right views) are generated at the decoder from both the depth map and watermarked centre view using the DIBR process. The watermark is extracted independently from the centre, left and right views which can be distributed individually as 2D content. The quality of the watermarked 3D video is evaluated by a subjective test and compared with that of a DIBR 3D image watermarking algorithm. The experimental results demonstrate that the proposed scheme provides superior performance to those of state-of-the-art approaches in terms of Gaussian noise addition, baseline distance adjustment and 3D camcording, as well as the attacks considered in the previous part of this study for 2D video

Inter-Subject Image Registration of Clinical Neck MRI Volumes using Discrete Periodic Spline Wavelet and Free Form Deformation

This paper presents a framework for inter-patient image registration which uses a multi-thresholds, multi-similarity measures and multi-transformations based on compactly supported spline and discrete periodic spline wavelets (DPSWs) using the Gauss-Newton gradient descent (GNGD) and gradient descent (GD) optimization methods. Our primary intellectual contribution is incorporating DPSWs in the transformation while another includes fusing out-of-range concept in a surface matching technique which is implemented by a multi-transformations and multi-similarity measures. In particular, as a true deformation cannot be achieved by single combination of transformation, similarity measure (SM) and optimization of a registration process, a moving image is required to be brought within the range of a registration. On the other hand, the surface matching technique involves an edge position difference (EPD) SM in which coarse to fine surfaces are matched using multiple thresholds with a spline-based free from deformation (FFD) method. The registration experiments were performed on 3D clinical neck magnetic resonance (MR) images, with the results showing that our proposed method provides good accuracy and robustness

Eighth International Conference on Digital Image Processing (ICDIP 2016)

Whiplash-associated disorder (WAD) is a commonly occurring injury that often results from neck trauma suffered in car accidents. However the cause of the condition is still unknown and there is no definitive clinical test for the presence of the condition. Researchers have begun to analyze the size of neck muscles and the presence of fatty infiltrates to help understand WAD. However this analysis requires a high precision delineation of neck muscles which is very challenging due to a lack of distinctive features in neck magnetic resonance imaging (MRI). This paper presents a novel atlas-based neck muscle segmentation method which employs discrete cosine-based elastic registration with affine initialization. Our algorithm shows promising results based on clinical data with an average Dice similarity coefficient (DSC) of 0.84±0.0004