Histogram Shifting Research Articles

A High Performance Reversible Watermarking Scheme Based on Histogram Shifting

摘要: 近年来,基于直方图平移的可逆水印算法因其生成水印图像质量高而被广泛研究.目前大部分相关水印算法是非盲的,需要额外传送峰值/零点对等边信息.已有的相关盲水印算法由于采用固定的峰值/零点对而性能较差.本文提出一种面向差值域多层嵌入的高性能直方图平移盲可逆水印算法,有关同步机制可保证在每层嵌入时都选择最优的峰值点和零点.对于单层嵌入,提出两步嵌入法(Two-step embedding,TSE)同步机制,将边信息嵌入到第一步生成的水印像素最低有效位以实现盲提取;对多层嵌入,则进一步提出链式嵌入同步机制,并在最后层采用两步嵌入法以保证水印盲提取.仿真结果表明,本文算法不但可以实现盲提取的要求,而且在算法性能方面较同类算法有显著的提高. 关键词: 图像水印 / 直方图平移 / 可逆水印 / 盲水印 / 两步嵌入法

Improving Various Reversible Data Hiding Schemes Via Optimal Codes for Binary Covers

In reversible data hiding (RDH), the original cover can be losslessly restored after the embedded information is extracted. Kalker and Willems established a rate-distortion model for RDH, in which they proved out the rate-distortion bound and proposed a recursive code construction. In our previous paper, we improved the recursive construction to approach the rate-distortion bound. In this paper, we generalize the method in our previous paper using a decompression algorithm as the coding scheme for embedding data and prove that the generalized codes can reach the rate-distortion bound as long as the compression algorithm reaches entropy. By the proposed binary codes, we improve three RDH schemes that use binary feature sequence as covers, i.e., an RS scheme for spatial images, one scheme for JPEG images, and a pattern substitution scheme for binary images. The experimental results show that the novel codes can significantly reduce the embedding distortion. Furthermore, by modifying the histogram shift (HS) manner, we also apply this coding method to one scheme that uses HS, showing that the proposed codes can be also exploited to improve integer-operation-based schemes.

Mean-Shift Algorithm Apply for Infrared Imaging Tracking

An improved algorithm based on the modified histogram & mean shift is proposed in order to deal with difficulties in tracking small target of infrared imaging under complex background. The new algorithm is based on a lower dimension combining characteristic weighted histogram, the analogical degree measurement is determined by the Bhattacharyya coefficient, and the target is located through the mean shift. In order to improve the precision and robustness of the modified mean shift algorithm, particle filtering is used to obtain the optimal position estimate. Test results show that, the tracking point fluctuation could be reduced to no more than 2 pixels with the modified algorithm, for the test case.

Improved Histogram Shifting Technique for Low Payload Embedding by Using a Rate-Distortion Model and Optimal Side Information Selection

Improved Histogram Shifting Technique for Low Payload Embedding by Using a Rate-Distortion Model and Optimal Side Information Selection

Reversible watermarking via extreme learning machine prediction

In this paper, we attempt to construct a novel framework of reversible watermarking. This work is based on the difference-image histogram shift. De-correlation is the core of high capacity data-hiding in histogram-shift techniques. For the sake of higher payload, we choose the down-sample pattern as reference set. For each layer, prediction points are obtained in terms of points from the reference set. The full-resolution image quality reconstructed determines to reversible watermarking performance. When existing the prior knowledge, an effective regression method named extreme learning machine is utilized to estimate missing pixels. It can yield high-quality recovery image. Compared to other better algorithms on state of the art, the proposed method achieves higher capacity gain of watermarked images with the similar distortion.

High-capacity reversible data hiding based on multi-histogram modification

Reversible data hiding is a technique that embeds a message into a host image with acceptable visual distortion and then recovers the image without any data loss while extracting the embedded message. The previous schemes mainly suffer from an unresolved problem that the imperceptibility of a marked image decreases severely as the embedding capacity increases. Extending the histogram modification technique, this study proposes a novel scheme that utilizes multiple histograms to increase embedding capacity while keeping marked-image quality. Unlike most histogram modification schemes, the multi-histogram scheme does not suffer from overflow and underflow during histogram shift. This scheme can yield the embedding capacity of 1 bit per pixel (bpp) at the PSNR of 48.13 db for a 512 × 512 grayscale image. To reduce the overhead during message embedding, the work further proposes an iterative multi-histogram scheme. Comprehensive experimental results show that both the schemes can achieve high embedding capacity and image quality.

Reversible Robust Data Hiding Scheme based on Histogram Shifting in Multiwavelet Domain

Reversible Robust Data Hiding Scheme based on Histogram Shifting in Multiwavelet Domain

Reversible Data Hiding for Btc-compressed Images Based on Bitplane Flipping and Histogram Shifting of Mean Tables

Reversible Data Hiding for Btc-compressed Images Based on Bitplane Flipping and Histogram Shifting of Mean Tables

Lossless Data Embedding in BTC Codes Based on Prediction and Histogram Shifting

This paper proposes a lossless data embedding method for Block Truncation Coding (BTC) compressed images based on prediction and histogram shifting techniques. Because BTC is easy to implement, and requires significantly less CPU cost, it has arouse widely attention in applications where real-time processing is demanded. For the existing lossless data embedding method in BTC codes, the decoder has to be specifically designed so that the spatial domain image can perfectly reconstructed from the compressed codes. Therefore, the application of these methods is limited. In the proposed embedding method, we slightly modified the quantization values of BCT codes to embed data losslessly, and a standard BTC decoder can be used to decode the BTC codes. The embedded secret messages can be extracted at the receiver side with the correct key. The experimental results revealed that the proposed method not only recovers the stego image to its original one, but also preserved a high image quality.

A new non-Gaussian evaluation method for ensemble forecasts based on analysis rank histograms

The verification of ensemble forecasts is an active field of research. Today, more and more weather forecasting centers implement ensemble forecasts in their operational weather prediction cycles, giving rise to the demand for reliable verification methods especially designed for probabilistic forecasting. Beside well known scores (such as the Brier score or the continuous ranked probability score) analysis rank histograms or Talagrand diagrams are very popular amongst the ensemble forecasting community. However, a shortcoming of this verification method is its graphical character. In this paper, we present a score which can easily be derived from analysis rank histograms. The so called β-score holds the advantage of expressing the graphical character of the histogram, and therefore the character of the ensemble spread, in just one single number. We show results of a β-score analysis of operational ensemble forecasts from different centers for different regions and forecast lead times. In addition to the β-score, we present the so called β-bias which quantifies the shift of analysis rank histograms to lower or higher values and therefore a relative measure of ensemble forecast bias. Results of the β-bias are also shown in this paper.

Duration distributions for different softness groups of gamma-ray bursts

Gamma-ray bursts (GRBs) are divided into two classes according to their durations. We investigate if the softness of bursts plays a role in the conventional classification of the objects. We employ the BATSE (Burst and Transient Source Experiment) catalog and analyze the duration distributions of different groups of GRBs associated with distinct softness. Our analysis reveals that the conventional classification of GRBs with the duration of bursts is influenced by the softness of the objects. There exists a bimodality in the duration distribution of GRBs for each group of bursts and the time position of the dip in the bimodality histogram shifts with the softness parameter. Our findings suggest that the conventional classification scheme should be modified by separating the two well-known populations in different softness groups, which would be more reasonable than doing so with a single sample. According to the relation between the dip position and the softness parameter, we get an empirical function that can roughly set apart the short-hard and long-soft bursts: SP = (0.100 ± 0.028)T 90 − (0.85 ± 0.18) , where SP is the softness parameter adopted in this paper.

Assessment of early vascular effects of the angiogenesis inhibitor sunitinib (SU) in renal cell carcinoma (RCC) by dynamic contrast enhanced MRI (DCE-MRI) and diffusion weight MRI (DWI) at 3 tesla (T).

3051 Background: This study assesses early vascular effects of SU in RCC pts with DCE-MRI and DWI at 3T. Methods: In 8 pts with abdominal RCC lesions, we performed 3T DCE-MRI and DWI at baseline, on d3 and d10 after start of SU. For DWI we used three gradient factors (b50-300-600 s/mm2). Apparent diffusion coefficient (ADC) maps were calculated for tumor and healthy liver tissue. DCE-MRI was performed after an iv bolus of Gadolinium (Gd)-DTPA using fast T1 measurements for 5 min. Mean kep and Ktrans were calculated and histogram analysis was performed. Tumor perfusion was measured after a second bolus of Gd-DTPA by dynamic T2* weighted measurements during 90 sec. VEGF plasma levels were measured on d0, d3 and d10. Results: In 8 RCC pts, SU did not result in significant changes in mean kep (s-1) and Ktrans (s-1) values in tumors or healthy liver tissue on d3 and d10. However, in 6 pts, the differences in mean kep values in tumors at d10 exceeded the repeatability coefficient. No significant kep and Ktrans histogram shift in tumor or healthy liver ROIs was observed. Two pts showed an increase in tumor mean kep values, one with objective progressive disease. All other pts had stable disease after 2 cycles of SU. In 2 pts a remarkable increase in kep values was observed in healthy liver tissue while in tumors their kep values decreased. Interestingly, ADC (x10-6 s/mm2) increased from baseline (mean 1174, range 868-1373) to d3 (mean 1315, range 1008-2097, p=0.036) and decreased to d10 (mean 1154, range 824-2005, p=0.029). D0 and d10 ADC values did not differ (p >0.1). This indicates enhanced Brownian movements of water molecules, possibly due to development of edema en necrosis which recovers at d10 due to loss of edema or organization of necrosis. VEGF plasma levels increased from baseline to day 10 (mean 0.55 ng/ml to 1.24 ng/ml, p=0.062). Conclusions: This is the first report of DWI at 3T in SU-treated RCC pts. SU significantly increased ADC at d3, with recurrence to baseline values at d10, possibly due to the development of edema and necrosis. DWI may serve as a potential biomarker for the effect of angiogenesis inhibitors. No significant financial relationships to disclose.

Foreword of Special Issue on “Information Education and Technological Application”

Foreword of Special Issue on “Information Education and Technological Application”

Electrostatic and dynamical effects of an aqueous solution on the zero-bias conductance of a single molecule: A first-principles study

The electrostatic and dynamical effects of an aqueous solution on the conductance of benzene-1,4-dithiolate are examined using the ab initio nonequilibrium Green's function method and Car-Parrinello molecular dynamics. The peak of the conductance histogram shifts downward by $0.01--0.02\text{ }{\text{G}}_{0}$, which is attributed to the electrostatic effects of the aqueous solution. Dynamical changes in molecular motion induced by the aqueous solution are observed in the molecular dynamics, resulting in emergence/disappearance of new peaks in the conductance histograms.

SU‐FF‐J‐75: Real‐Time MR Tumour Tracking and Dose Adaptation

Purpose: To develop a real‐time (while the patient is being irradiated) tumour tracking and dose adaptation algorithm that can operate within a novel Linear accelerator‐Magnetic Resonance imaging (Linac‐MR) system. Current emphasis is given to lung tumour, which shows the most extensive and abrupt motion. Method and Materials: The auto‐contouring algorithm to automatically identify the shape of the tumour from each MR image is comprised of an autocorrelation technique for image matching, and Histogram Shifting (HS) algorithm for edge detection. A MR compatible motion phantom was built to simulate the motion of tumours (ex: lung tumours) and to perform various dosimetric measurements. The 4D MR images of this phantom and volunteers were used to evaluate the auto‐contouring algorithm. To conform the radiation beam, a Multi‐Leaf Collimator (MLC) controller is being developed using Field Programmable Gate Array (FPGA) based electronics. To compensate for the time delay between MR imaging and irradiating instances, a motion prediction algorithm was developed using a Kalman filter. Results: The auto‐contouring algorithm showed successful tumour tracking and contouring capabilities in the 4D MR images of thoracic region and phantom. The motion prediction algorithm was evaluated by using a modified cosine model, motion phantoms, and fluoroscopic patient data. In most cases, the algorithm predicted the position of tumour correctly more than 95% of the total treatment time. The FPGA based electronics demonstrated its real‐time MLC controlling capability. Various 1‐D lung tumour motions were simulated by the MR motion phantom, which was used to evaluate our algorithms. Conclusion: This work indicates the potential of Linac‐MR system for (1) auto‐contouring capability of tumours in real‐time MR image (more than 4 frames per second) (2) radiation beam conformity to the shape of tumours (3) accurate tumour tracking ability by developing motion prediction algorithm (4) beam intensity modification.

Sensor-based Behavior Control for an Autonomous Underwater Vehicle

In this paper, we evaluate a set of core functions that allow an underwater robot to perform surveillance under operator control. Specifically, we are interested in behaviors that facilitate the monitoring of organisms on a coral reef, and we present behaviors and interaction modes for a small underwater robot. In particular, we address some challenging issues arising from the underwater environment: visual processing, interactive communication with an underwater crew and, finally, orientation and motion of the vehicle through a hovering mode. The visual processing consists of target tracking using various techniques (color segmentation, color histogram and mean shift). Communication underwater is achieved through printed cards with robustly identifiable visual markers on them. Finally, the hovering gait developed for this vehicle relies on the planned motion of six flippers to generate the appropriate forces.

LXRα Enhances Lipid Synthesis in SZ95 Sebocytes

Differentiation of sebocytes is strongly associated with enhanced lipid synthesis and accumulation in the cells. Liver X receptors (LXRs) are members of the nuclear receptor superfamily, which play a critical role in cholesterol homeostasis and lipid metabolism. We examined whether LXRalpha regulated lipid synthesis in the immortalized human sebaceous gland cell line SZ95. When the SZ95 sebocytes were treated with the ligand of LXR such as TO901317 or 22(R)-hydroxycholesterol, lipid droplets were accumulated in the majority of cells when examined by Oil Red O staining. The expression of the known LXR targets, such as fatty acid synthase and sterol regulatory-binding protein-1, was induced by TO901317. TO901317 treatment increased expression of LXRalpha but not that of LXRbeta. Transfection of antisense LXRalpha significantly decreased TO901317-induced target gene expression and lipid droplet accumulation, suggesting a major role of LXRalpha in differentiation of sebocytes. Further, TO901317 decreased the expression of cyclooxygenase-2 and inducible nitric oxide synthase that was induced by lipopolysaccharide treatment. Together, these results indicate that important roles of LXRalpha in differentiation and inflammatory signaling in sebaceous glands. Thus, we suggest that LXR ligands could provide a new class of therapeutic agents for sebaceous gland-associated disorders such as seborrhea and acne.

Novel correction methods as alternatives for the six-dimensional correction in CyberKnife treatment

During CyberKnife treatment, the 6D correction method is used to correct patient positional errors, including rotational ones. We developed novel correction methods for translating rotational errors into 3D, with the aim of making their correction safer than with 6D correction and as accurate as possible. These novel correction methods were named the gravity correction and the beam correction method. With the gravity correction method, the beam coordinates after rotation are corrected to match the tumor gravity point with 3D translational components translated by the affine transformation matrix. For beam correction, the beam coordinates are corrected to match the translated tumor target coordinates for each treatment beam. The effectiveness and impact of these methods were demonstrated by means of dose volume histogram (DVH) shift evaluation. For analysis of the treatment data of 10 patients, the treatment beam was rotated in three patterns of rotational degree and corrected with the two methods. The amount of tumor gravity point shift in the rotation was also calculated, and the deterioration of the tumor DVH was studied. In the case of +/-1 degrees , +/-3 degrees , and +/-1 degrees rotation for the X, Y, Z axes, the tumor gravity point of all 10 patients moved around 2.4 mm on average. Tumor DVH was deteriorated worse as the distance between the tumor gravity point and the rotational origin became more distant. With the planned D90, which represents the dose above which 90% of the tumor volume is irradiated set at 100%, the postrotational average D90 dose deteriorated to 96.12% after (+/-1 degrees , +/-3 degrees , and +/-1 degrees ) rotation. The dose was improved to 99.9% (SD +/- 0.41) after the gravity correction, or to 99.87% (SD +/- 0.55) after the beam correction. The correction methods developed by us can correct tumor DVH findings to the same degree as with 6D correction and are safer because the movement required for correcting the linac is not rotational but translational only.

Irt > t schedule controlled behavior in ‘learned-helpless’ rats: Effects from a cannabinoid agonist

Human depression is partly a congenital disorder. Aspects of the behavior accompanying depression can be magnified by genetic manipulation of bred animal species. Learned Helplessness (LH) is a trait-mark behavior that successfully breeds in rodents. Here, ‘congenital’ LH (cLH) rats were trained to recognize and respond to 12 s long interval cues (irt > 12 s schedule). Rats compliant to an irt > t schedule will space responses evenly and respond rhythmically. Irt > t schedule derived data are plotted in histograms showing irt (interresponse time) frequencies. A pause response peak emerges, for outbred rats, at irt values approximating the minimum interval for reinforcement. cLH rats [ n = 9] complied poorly to schedule contingencies when diluent (vehicle) was injected before testing. Moderate and high dose injections of a CB 1 receptor selective agonist drug (AM 411), however, increased operant schedule compliance and normalized the cLH rats' irt > t histogram distributions. Performance indicators for cLH rats are presented alongside coordinate measures from a comparison group [ n = 5] of normally bred Sprague-Dawley (SD) rats. In both cLH and SD rats, treatment session histograms revealed shifts of the pause response peak not accompanied by a change in motor responsiveness. The irt > 12 s histogram shifts were absent when AM 411 dosages were arranged to follow pre-medication injections of a CB 1 receptor selective antagonist drug (AM 251). In short, AM 411 increased timing acuity in rats prone to behavioral despair but had opposite timing effects in normally bred SD rats.

Study of the influence of an electric motor on statistical fluctuations of radioactive decay

The experimental results confirming the remote influence of an electric motor on changes of fluctuations of nucleus decay probability and hence on the shift and shape of statistical histograms of the number of gamma-radiation pulses are obtained. The decay rate is indirectly influenced by the physical field that arises as a result of rotation and is not connected with the electromagnetic component.