Intra-frame Distortion Research Articles

Adaptive HEVC video steganography based on distortion compensation optimization

With the development of digital video communication, the steganography based on H.265/HEVC has attracted more and more attention. Because of higher security and better compatibility, the traditional video steganography often used quantized discrete cosine transform (QDCT) or quantized discrete sine transform (QDST) coefficients to embed secret messages. However, the QDCT/QDST-based steganographic methods will cause distortion drift seriously. Although the distortion compensation optimization method can eliminate the intra-frame distortion drift, it ignored the influence of inter-frame distortion. This limitation prompts authors to propose an adaptive HEVC steganography, which eliminates the intra-frame distortion drift while reducing inter-frame distortion. First, the distortion of intra-block and inter-block is analyzed with the prediction and transform process. Then, the corresponding embedding influence is defined, which includes intra-block distortion, inter-frame distortion accumulation, the block texture complexity and the cost of coefficient groups. Finally, the proposed adaptive cost function is designed based on the above definition and the syndrome trellis codes (STC) is used for embedding. The experimental results show that the proposed method has better performance compared with the state-of-the-art coefficient-based steganography in visual quality, bit rate increment and anti-steganalysis.

Reversible Data Hiding Scheme Based on Coefficient Pair Mapping for Videos H.264/AVC without Distortion Drift

Reversible data hiding is a technique for embedding secret data into a cover media. Such technique has the ability to recover marked cover media to its original version after extracting the secret data. In this paper, a new reversible data hiding algorithm for videos H.264/AVC is proposed to improve the embedding capacity while the distortion drift is prevented. To embed the secret data into videos H.264/AVC without any intra-frame distortion drift, in our proposed scheme, the relationship of QDCT coefficients is explored. Then, a coefficient pair mapping mechanism in 2D histogram is introduced for embedding data. The experimental results demonstrated that the proposed scheme obtains reversibility. The proposed scheme prevents intra-frame distortion drift on the marked videos. In addition, the embedding capacity of the proposed scheme is superior to that of existing schemes while guaranteeing the high visual quality of marked videos.

A HEVC Video Steganalysis Against DCT/DST-Based Steganography

The development of video steganography has put forward a higher demand for video steganalysis. This paper presents a novel steganalysis against discrete cosine/sine transform (DCT/DST)-based steganography for high efficiency video coding (HEVC) videos. The new steganalysis employs special frames extraction (SFE) and accordion unfolding (AU) transformation to target the latest DCT/DST domain HEVC video steganography algorithms by merging temporal and spatial correlation. In this article, the distortion process of DCT/DST-based HEVC steganography is firstly analyzed. Then, based on the analysis, two kinds of distortion, the intra-frame distortion and the inter-frame distortion, are mainly caused by DCT/DST-based steganography. Finally, to effectively detect these distortions, an innovative method of HEVC steganalysis is proposed, which gives a combination feature of SFE and a temporal to spatial transformation, AU. The experiment results show that the proposed steganalysis performs better than other methods.

Correcting intra-volume distortion for AO-OCT using 3D correlation based registration.

Adaptive optics (AO) based ophthalmic imagers, such as scanning laser ophthalmoscopes (SLO) and optical coherence tomography (OCT), are used to evaluate the structure and function of the retina with high contrast and resolution. Fixational eye movements during a raster-scanned image acquisition lead to intra-frame and intra-volume distortion, resulting in an inaccurate reproduction of the underlying retinal structure. For three-dimensional (3D) AO-OCT, segmentation-based and 3D correlation based registration methods have been applied to correct eye motion and achieve a high signal-to-noise ratio registered volume. This involves first selecting a reference volume, either manually or automatically, and registering the image/volume stream against the reference using correlation methods. However, even within the chosen reference volume, involuntary eye motion persists and affects the accuracy with which the 3D retinal structure is finally rendered. In this article, we introduced reference volume distortion correction for AO-OCT using 3D correlation based registration and demonstrate a significant improvement in registration performance via a few metrics. Conceptually, the general paradigm follows that developed previously for intra-frame distortion correction for 2D raster-scanned images, as in an AOSLO, but extended here across all three spatial dimensions via 3D correlation analyses. We performed a frequency analysis of eye motion traces before and after intra-volume correction and revealed how periodic artifacts in eye motion estimates are effectively reduced upon correction. Further, we quantified how the intra-volume distortions and periodic artifacts in the eye motion traces, in general, decrease with increasing AO-OCT acquisition speed. Overall, 3D correlation based registration with intra-volume correction significantly improved the visualization of retinal structure and estimation of fixational eye movements.

A robust steganography method for HEVC based on secret sharing

This paper presents a robust steganography method for HEVC based on secret sharing. To prevent intra-frame distortion drift, three Classes of intra-frame prediction are defined. To improve the robustness of the secret message, the embedded message has been encoded into n sub-secrets by using (t, n)-threshold secret sharing. Then the encoded message is embedded into the multi-coefficients of the selected 4 × 4 luminance DST blocks which meet the Classes mentioned above. When the test video faced with different loss-rates, the survival rate of the proposed steganography method has increased by around 24.27%, 27.38%, 61.91% and 32.26% compared with Swati, Hayat, and Shahid (2014), respectively; the survival rate of the proposed steganography method has increased by around 28.74%, 34.60%, 56.05% and 41.40% compared with Liu, Liu, and Zhao (2017), respectively; when the loss-rate is less than 15%, the proposed steganography method can get 100% survival rate. And the experiments prove that the proposed method can achieve high performance than previously video steganography methods based on HEVC, especially for visual quality and robustness performance.

An adaptive steganographic scheme for H.264/AVC video with distortion optimization

With the popularity of streaming media, data hiding in H.264/AVC video streams has attracted more and more attention. However, how to achieve high secure video steganography while preventing intra-frame distortion drift is a challenging task. In this paper, based on Syndrome–Trellis Code(STC), we propose a secure steganographic scheme using Quantized Discrete Cosine Transform (QDCT) coefficients of I-frames. We first present a theoretical analysis of the block distortion, which consists of inter-block distortion caused by data embedding in reference pixels of adjacent blocks and inner-block distortion caused by data embedding in local pixels of current block. Based on block distortion analysis, we propose a novel distortion optimization strategy by avoiding inter-block distortion and decreasing inner-block distortion. The cost function is constructed based on block distortion, bit-rate change and texture complexity of DCT block. Compared with distortion compensation methods, the proposed method not only considers the distortion optimization but also introduces secure steganographic scheme. Experimental results show that the proposed scheme can resist the state-of-the-art steganalytic method while achieving high visual quality.

IMU-Aided High-Frequency Lidar Odometry for Autonomous Driving

For autonomous driving, it is important to obtain precise and high-frequency localization information. This paper proposes a novel method in which the Inertial Measurement Unit (IMU), wheel encoder, and lidar odometry are utilized together to estimate the ego-motion of an unmanned ground vehicle. The IMU is fused with the wheel encoder to obtain the motion prior, and it is involved in three levels of the lidar odometry: Firstly, we use the IMU information to rectify the intra-frame distortion of the lidar scan, which is caused by the vehicle’s own movement; secondly, the IMU provides a better initial guess for the lidar odometry; and thirdly, the IMU is fused with the lidar odometry in an Extended Kalman filter framework. In addition, an efficient method for hand–eye calibration between the IMU and the lidar is proposed. To evaluate the performance of our method, extensive experiments are performed and our system can output stable, accurate, and high-frequency localization results in diverse environment without any prior information.

Adaptive Video Data Hiding through Cost Assignment and STCs

With the increasing popularity of digital video communication, video data hiding has become an active research topic in covert communication and privacy protection. Traditional video data hiding methods often use quantized discrete cosine transform (QDCT) coefficients to carry a sufficient payload. However, since QDCT coefficients expose texture features and motion characteristics of the present video frame heavily, data embedding with QDCT coefficients may lead to significant intra-frame distortion and inter-frame distortion drift. To avoid obvious visual artifacts and keep bit-rate within a satisfactory level of the marked video, data embedding in QDCT coefficients should take into account both the intra-frame and inter-frame distortion impacts. It motivates the authors to propose an efficient cost assignment-based video data hiding method in this paper. The proposed cost assignment method aims to accurately evaluate the data embedding distortion. Specifically, the proposed scheme considers intra-frame changes and intra-frame distortion drift, for which the texture and motion changes of frames can be measured. The frame position is also used to reflect a cumulative distortion difference of multiple frames. For data embedding, syndrome-trellis code (STC) is adopted to minimize the overall distortion. Experimental results show that the proposed method significantly outperforms existing works in terms of payload-distortion performance.

An Intra-Drift-Free Robust Watermarking Algorithm in High Efficiency Video Coding Compressed Domain

The existing watermarking algorithms in H.265/high efficiency video coding (HEVC) compressed domain cannot achieve intra-frame distortion drift-free and resist the recompression and signal processing attacks simultaneously. Therefore, the application of HEVC watermarking in copyright protection is limited in practice. To solve the problem, this paper proposes an intra-drift-free robust watermarking algorithm, which uses a multi-coefficients modification method to embed the watermark into intra prediction residual pixels of 4 × 4 luminance transform blocks in the spatial domain. Based on the spatial-domain embedding method, watermark information can be extracted from the blocks that have been attacked and merged into 8 × 8 size, which improves the robustness. To further improve the performance of the watermarking algorithm, the proposed algorithm uses a combination of three thresholds according to the application requirements. Experimental results on a publicly available video database (JCT-VC) have justified the effectiveness of the proposed algorithm which has better imperceptibility and robustness than existing algorithms. In addition, the proposed algorithm has high real-time performance and is suitable for application scenarios where the video is distributed on a large scale.

High Embedding Capacity Data Hiding Algorithm for H.264/AVC Video Sequences without Intraframe Distortion Drift

Data hiding is a technique that allows secret data to be delivered securely by embedding the data into cover digital media. In this paper, we propose a new data hiding algorithm for H.264/advanced video coding (AVC) of video sequences with high embedding capacity. In the proposed scheme, to embed secret data into the quantized discrete cosine transform (QDCT) coefficients of I frames without any intraframe distortion drift, some embeddable coefficient pairs are selected in each block, and they are divided into two different groups, i.e., the embedding group and the averting group. The embedding group is used to carry the secret data, and the averting group is used to prevent distortion drift in the adjacent blocks. The experimental results show that the proposed scheme can avoid intraframe distortion drift and guarantee low distortion of video sequences. In addition, the proposed scheme provides enhanced embedding capacity compared to previous schemes. Moreover, the embedded secret data can be extracted completely without the requirement of the original secret data.

A new data hiding method for H.265/HEVC video streams without intra-frame distortion drift

This paper presents a readable H.265/HEVC data hiding method. First, three conditions of the directions of intra-frame prediction and the multi-coefficients are given to avert intra-frame distortion drift. Then, the message is embedded into the multi-coefficients of the 4 × 4 luminance DST blocks of the selected frames which meet the specific conditions. The experimental results show that this data hiding algorithm can effectively avert intra-frame distortion drift and get good visual quality.

A Robust and Improved Visual Quality Data Hiding Method for HEVC

This paper presents a novel and robust data hiding method based on H.265 /High Efficiency Video Coding ( HEVC ) standard. To improve the robustness of data hiding, the embedded data are first encoded into the encoded data by using the BCH syndrome code ( BCH code ) technique. To improve the visual quality of data hiding, three groups of the prediction directions are provided to limit the intra-frame distortion drift. Then, the encoded data are embedded into the multi-coefficients of the selected $4 \times 4$ luminance discrete sine transform blocks, which meet the groups. It is experimentally proven that the proposed method can achieve greater robustness, better visual quality, and higher embedding capacity than previously studied methods.

De-warping of images and improved eye tracking for the scanning laser ophthalmoscope.

A limitation of scanning laser ophthalmoscopy (SLO) is that eye movements during the capture of each frame distort the retinal image. Various sophisticated strategies have been devised to ensure that each acquired frame can be mapped quickly and accurately onto a chosen reference frame, but such methods are blind to distortions in the reference frame itself. Here we explore a method to address this limitation in software, and demonstrate its accuracy. We used high-speed (200 fps), high-resolution (~1 μm), flood-based imaging of the human retina with adaptive optics to obtain “ground truth” information on the retinal image and motion of the eye. This information was used to simulate SLO video sequences at 20 fps, allowing us to compare various methods for eye-motion recovery and subsequent minimization of intra-frame distortion. We show that a) a single frame can be near-perfectly recovered with perfect knowledge of intra-frame eye motion; b) eye motion at a given time point within a frame can be accurately recovered by tracking the same strip of tissue across many frames, due to the stochastic symmetry of fixational eye movements. This approach is similar to, and easily adapted from, previously suggested strip-registration approaches; c) quality of frame recovery decreases with amplitude of eye movements, however, the proposed method is affected less by this than other state-of-the-art methods and so offers even greater advantages when fixation is poor. The new method could easily be integrated into existing image processing software, and we provide an example implementation written in Matlab.

High-speed adaptive optics line scan confocal retinal imaging for human eye.

PurposeContinuous and rapid eye movement causes significant intraframe distortion in adaptive optics high resolution retinal imaging. To minimize this artifact, we developed a high speed adaptive optics line scan confocal retinal imaging system.MethodsA high speed line camera was employed to acquire retinal image and custom adaptive optics was developed to compensate the wave aberration of the human eye’s optics. The spatial resolution and signal to noise ratio were assessed in model eye and in living human eye. The improvement of imaging fidelity was estimated by reduction of intra-frame distortion of retinal images acquired in the living human eyes with frame rates at 30 frames/second (FPS), 100 FPS, and 200 FPS.ResultsThe device produced retinal image with cellular level resolution at 200 FPS with a digitization of 512×512 pixels/frame in the living human eye. Cone photoreceptors in the central fovea and rod photoreceptors near the fovea were resolved in three human subjects in normal chorioretinal health. Compared with retinal images acquired at 30 FPS, the intra-frame distortion in images taken at 200 FPS was reduced by 50.9% to 79.7%.ConclusionsWe demonstrated the feasibility of acquiring high resolution retinal images in the living human eye at a speed that minimizes retinal motion artifact. This device may facilitate research involving subjects with nystagmus or unsteady fixation due to central vision loss.

Effects of Intraframe Distortion on Measures of Cone Mosaic Geometry from Adaptive Optics Scanning Light Ophthalmoscopy.

PurposeTo characterize the effects of intraframe distortion due to involuntary eye motion on measures of cone mosaic geometry derived from adaptive optics scanning light ophthalmoscope (AOSLO) images.MethodsWe acquired AOSLO image sequences from 20 subjects at 1.0, 2.0, and 5.0° temporal from fixation. An expert grader manually selected 10 minimally distorted reference frames from each 150-frame sequence for subsequent registration. Cone mosaic geometry was measured in all registered images (n = 600) using multiple metrics, and the repeatability of these metrics was used to assess the impact of the distortions from each reference frame. In nine additional subjects, we compared AOSLO-derived measurements to those from adaptive optics (AO)-fundus images, which do not contain system-imposed intraframe distortions.ResultsWe observed substantial variation across subjects in the repeatability of density (1.2%–8.7%), inter-cell distance (0.8%–4.6%), percentage of six-sided Voronoi cells (0.8%–10.6%), and Voronoi cell area regularity (VCAR) (1.2%–13.2%). The average of all metrics extracted from AOSLO images (with the exception of VCAR) was not significantly different than those derived from AO-fundus images, though there was variability between individual images.ConclusionsOur data demonstrate that the intraframe distortion found in AOSLO images can affect the accuracy and repeatability of cone mosaic metrics. It may be possible to use multiple images from the same retinal area to approximate a “distortionless” image, though more work is needed to evaluate the feasibility of this approach.Translational RelevanceEven in subjects with good fixation, images from AOSLOs contain intraframe distortions due to eye motion during scanning. The existence of these artifacts emphasizes the need for caution when interpreting results derived from scanning instruments.

Robust HEVC Video Watermarking Scheme Based on Repetition- BCH Syndrome Code

High efficiency video coding (HEVC) was recently introduced two years ago as the new standard for video coding. This new codec will be the most widely prevalent standard. Because of the industry needs for authentication and copyright protection methodologies the robustness of this standard is required to be developed. This paper presents the first robust digital watermarking method for the HEVC based on Repetition- BCH syndrome code technique without intra-frame distortion drift. The objective of this article is to implement a new technique that can offer high robustness against noise channel errors and increase the error detection rate in the HEVC video sequences transmitted over noisy communication channels. The proposed technique does not significantly affect the video quality, nor does it escalate the bitrate. The results show that the proposed technique offers greater robustness against noise channel while preserving good quality for extracted watermark. The proposed technique significantly contributes to the performance of the error detection and correction. In addition, this technique can recover the watermark when the watermarked frames dropping rate is less than 20%.

A new data hiding method for H.264 based on secret sharing

This paper proposes a new data hiding method for H.264 without intra-frame distortion drift. The embedded secret data is first distributed into n sub-secrets with matrix equation by using Shamir׳s (t, n)-threshold secret sharing. Then we choose the block with prediction mode and embed the embedded data into discrete cosine transform (DCT) coefficients of the selected block. Finally, we recover the original video as much as possible when the hidden data is extracted out by using the t sub-secrets of the video frames. The experimental results show that this new robust data hiding method not only can get more robustness, effectively avert intra-frame distortion drift and get good visual quality, but also can protect the original video.

A reversible data hiding method for H.264 with Shamir’s (t, n)-threshold secret sharing

This paper proposes a new robust reversible data hiding scheme for H.264. The embedded data is first distributed into n sub-secrets with matrix equation by using Shamir’s (t, n)-threshold secret sharing to improve the robustness of the embedded data. Then we choose the block with prediction mode and embed the sub-secrets into the coefficients of the 4×4 discrete cosine transform (DCT) block of the selected frames which meet our conditions to avert the distortion drift. The experimental results show that this new robust reversible data hiding algorithm can get more robustness, effectively avert intra-frame distortion drift and get good visual quality.

Research on a Robust Method for Image Steganography Transmission in Network

Images carrying the important information are often cracked by hackers when they are transmitted in the net- work. We propose a method in the paper for avoiding information leakage. It presents some significant evaluation pa- rameters to analyze image scrambling algorithms for encryption level. Then images are encrypted with the algorithm and transmitted in the network by hiding in the open video. In order to prevent the loss of packet or frame, we advance a ro- bust data hiding method which can use paired-coefficient and BCH code to recover error bit. It encodes the secret infor- mation with different BCH codes and embeds them into the paired-coefficients positions. The experimental results show that the method can avert intra-frame distortion drift and achieve high error resilience capacity. The research has a certain reference value and guiding significance for image steganography.

A robust reversible data hiding scheme for H.264 without distortion drift

This paper proposes a robust readable reversible data hiding scheme in H.264/AVC. We encode the embedded data using BCH syndrome code (BCH) before data hiding to improve robustness, then we embed the encoded data into the quantized discrete cosine transform (DCT) coefficients of the 4×4 blocks of I frames which meet the directions of intra-frame prediction, and the directions of intra-frame prediction are utilized to avert the distortion drift. The experimental results show that this new robust reversible data hiding algorithm can get more robustness, effectively avert intra-frame distortion drift and get good visual quality.