scholarly journals Image Encryption Scheme Based on Multiscale Block Compressed Sensing and Markov Model

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1297
Author(s):  
Yuandi Shi ◽  
Yinan Hu ◽  
Bin Wang
Keyword(s):  
Compressed Sensing ◽  
Markov Model ◽  
Image Encryption ◽  
Sampling Rate ◽  
Coefficient Matrix ◽  
Poor Quality ◽  
Encryption Scheme ◽  
Block Compressed Sensing ◽  
The Difference

Many image encryption schemes based on compressed sensing have the problem of poor quality of decrypted images. To deal with this problem, this paper develops an image encryption scheme by multiscale block compressed sensing. The image is decomposed by a three-level wavelet transform, and the sampling rates of coefficient matrices at all levels are calculated according to multiscale block compressed sensing theory and the given compression ratio. The first round of permutation is performed on the internal elements of the coefficient matrices at all levels. Then the coefficient matrix is compressed and combined. The second round of permutation is performed on the combined matrix based on the state transition matrix. Independent diffusion and forward-backward diffusion between pixels are used to obtain the final cipher image. Different sampling rates are set by considering the difference of information between an image’s low- and high-frequency parts. Therefore, the reconstruction quality of the decrypted image is better than that of other schemes, which set one sampling rate on an entire image. The proposed scheme takes full advantage of the randomness of the Markov model and shows an excellent encryption effect to resist various attacks.

The Quality Analysis of Hallux Valgus Videos on YouTube

2021 ◽  
Author(s):  
Enes Sari ◽  
Levent FAZLI Umur
Keyword(s):  
Hallux Valgus ◽  
Information Quality ◽  
Statistical Significance ◽  
Poor Quality ◽  
Quality Analysis ◽  
Accurate Information ◽  
Youtube Videos ◽  
The Mean ◽  
The Difference

BACKGROUND:The aim of this study was to evaluate the information quality of YouTube videos on hallux valgus. METHODS:A YouTube search was performed using the keyword 'hallux valgus' to determine the first 300 videos related to hallux valgus. A total of 54 videos met our inclusion criteria and evaluated for information quality by using DISCERN, Journal of the American Medical Association (JAMA) and hallux valgus information assessment (HAVIA) scores. Number of views, time since the upload date, view rate, number of comments, number of likes, number of dislikes, video power index (VPI) values were calculated to determine video popularity. Video length (sec), video source and video content were also noted. The relation between information quality and these factors were statistically evaluated. RESULTS:The mean DISCERN score was 30.35{plus minus}11.56 (poor quality) (14-64), the mean JAMA score was 2.28{plus minus}0.96 (1-4), and the mean HAVIA score was 3.63{plus minus}2.42 (moderate quality) (0.5-8.5). Although videos uploaded by physicians had higher mean DISCERN, JAMA, and HAVIA scores than videos uploaded by non-physicians, the difference was not statistically significant. Additionally, view rates and VPI values were higher for videos uploaded by health channels, but the difference did not reach statistical significance. A statistically significant positive correlation was found between video length and DISCERN (r= 0.294, p= 0.028), and HAVIA scores (r= 0.326, p= 0.015). CONCLUSIONS:This present study demonstrated that the quality of information available on YouTube videos about hallux valgus was low and insufficient. Videos containing accurate information from reliable sources are needed to educate patients on hallux valgus, especially in less frequently mentioned topics such as postoperative complications and healing period.

scholarly journals Image Encryption Scheme with Compressed Sensing Based on New Three-Dimensional Chaotic System

Entropy ◽  
2019 ◽  
Vol 21 (9) ◽  
pp. 819 ◽  
Author(s):  
Yaqin Xie ◽  
Jiayin Yu ◽  
Shiyu Guo ◽  
Qun Ding ◽  
Erfu Wang
Keyword(s):  
Compressed Sensing ◽  
Image Encryption ◽  
Chaotic System ◽  
Three Dimensional ◽  
Encryption Algorithm ◽  
Encryption Scheme ◽  
High Complexity ◽  
Measurement Matrix ◽  
The Core ◽  
New Chaotic System

In this paper, a new three-dimensional chaotic system is proposed for image encryption. The core of the encryption algorithm is the combination of chaotic system and compressed sensing, which can complete image encryption and compression at the same time. The Lyapunov exponent, bifurcation diagram and complexity of the new three-dimensional chaotic system are analyzed. The performance analysis shows that the chaotic system has two positive Lyapunov exponents and high complexity. In the encryption scheme, a new chaotic system is used as the measurement matrix for compressed sensing, and Arnold is used to scrambling the image further. The proposed method has better reconfiguration ability in the compressible range of the algorithm compared with other methods. The experimental results show that the proposed encryption scheme has good encryption effect and image compression capability.

Life Cycle and Growth of Sericostoma personatum Spence (Trichoptera, Sericostomatidae) in a Danish Spring

1973 ◽  
Vol 4 (4) ◽  
pp. 323-327 ◽  
Keyword(s):  
Life Cycle ◽  
Growth Retardation ◽  
Poor Quality ◽  
The Poor ◽  
Spring Area ◽  
The Difference ◽  
Slight Growth ◽  
Lower Temperature

AbstractIn a Danish spring the life cycle of Sericostoma personatum Spence (syn. S. pedemontanum Mac-Lachlan) took three years. A comparison is made with a I½ year life cycle reported by Elliott (I969). The poor quality of the food and lower temperature in the spring area are suggested as explanations of the difference. A slight growth retardation was found for all three year classes in winter and was referred to lower temperatures.

scholarly journals Correlating Coating Quality of Coverage with Rheology for Mica-Based Paints

2020 ◽  
Vol 30 (1) ◽  
pp. 119-129
Author(s):  
Jacob Anderson ◽  
Shailesh Shori ◽  
Esmaiel Jabbari ◽  
Harry J. Ploehn ◽  
Francis Gadala-Maria ◽  
...  
Keyword(s):  
Shear Stress ◽  
Hysteresis Loops ◽  
Poor Quality ◽  
Gradual Change ◽  
Visual Appearance ◽  
The Difference ◽  
Good Strain ◽  
Frequency Sweeps ◽  
Visual Properties

Abstract This paper examines the relationship between rheology and the qualitative appearance of dried, mica-based paint coatings used in the aerospace industry. The goal is to identify key rheological characteristics indicative of poor coating visual appearance, providing a screening tool to identify unsatisfactory paint formulations. Four mica paints were studied, having coating visual appearances ranging from very poor to very good. Strain sweeps indicated that the poor-quality paints have a smaller % strain midpoint in the linear visco-elastic range; while the good-quality paints have a lower G’/G” cross-over point in frequency sweeps. Thixotropy experiments utilizing single and multiple-loop hysteresis cycles plotting shear stress as a function of shear rate showed that the base mica paints with good appearance had nearly constant, reversible profiles in the forward and the backward directions; while the mica paints with poor appearance were irreversible with a noticeable gradual change in shear stress as more loops are run. The difference in area between the forward and the reverse curves was determined, leading to a quantifiable criterion that can differentiate good paints from poor paints with significance testing. This work would establish the first rheology model using hysteresis loops to predict the visual properties of mica-based paints.

scholarly journals A General Rate-Distortion Optimization Method for Block Compressed Sensing of Images

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1354
Author(s):  
Qunlin Chen ◽  
Derong Chen ◽  
Jiulu Gong
Keyword(s):  
Compressed Sensing ◽  
Sampling Rate ◽  
Rate Distortion ◽  
Optimization Method ◽  
Rate Model ◽  
Bit Rate ◽  
Unified Framework ◽  
Uniform Quantization ◽  
Block Compressed Sensing ◽  
Predictive Quantization

Block compressed sensing (BCS) is a promising technology for image sampling and compression for resource-constrained applications, but it needs to balance the sampling rate and quantization bit-depth for a bit-rate constraint. In this paper, we summarize the commonly used CS quantization frameworks into a unified framework, and a new bit-rate model and a model of the optimal bit-depth are proposed for the unified CS framework. The proposed bit-rate model reveals the relationship between the bit-rate, sampling rate, and bit-depth based on the information entropy of generalized Gaussian distribution. The optimal bit-depth model can predict the optimal bit-depth of CS measurements at a given bit-rate. Then, we propose a general algorithm for choosing sampling rate and bit-depth based on the proposed models. Experimental results show that the proposed algorithm achieves near-optimal rate-distortion performance for the uniform quantization framework and predictive quantization framework in BCS.

scholarly journals Adaptive Multiscale Block Compressed Sensing of Images based on Gray Level Co- Occurrence Matrix

2020 ◽  
Vol 13 (5) ◽  
pp. 169-175
Author(s):  
Jinfeng Li ◽  
◽  
Jinnan Guo ◽  
Shun Cao ◽  
Yutong Zhao
Keyword(s):  
Compressed Sensing ◽  
High Frequency ◽  
Sampling Rate ◽  
Texture Features ◽  
Gray Level ◽  
Limited Sampling ◽  
Block Compressed Sensing ◽  
Frequency Components ◽  
Image Edges ◽  
Occurrence Matrix

In conventional block compressed sensing (BCS), the images are divided into small fixed-size blocks sampled at the same sub-rate. The sparsities and high-frequency components of the images are ignored, and the reconstruction qualities of the complex texture images are poor. An adaptive multiscale variant of the block compressed sensing was proposed to reconstruct the texture details of the images. The texture features of the images were obtained from the high-frequency components by the three-level wavelet transform and analyzed on the basis of the gray level co-occurrence matrix. A mathematical model was established to adjust the block sizes of the images automatically and allocate the limited sampling resource adaptively. The smoothed projected Landweber (SPL) was utilized to reconstruct the images. The accuracy of the proposed algorithm was verified by the simulation experiments. Results demonstrate that the texture details of the reconstructed images are abundant. The image edges are also clear, and the blocking artifacts are effectively eliminated. The reconstruction qualities of images, especially the partial images, are considerably improved at different sub-sampling rates. The proposed algorithm achieves a 2.42–3.3 dB gain in reconstruction PSNR for the Barbara image over the original BCS-SPL at a sub-sampling rate of 0.3. No remarkable differences are noted between the reconstructed and original texture blocks in visual sensation. The proposed algorithm provides evidence for the compression and reconstruction of the images with complex texture details.

Mitigating imperfect data validity in administrative data PSIs: a method for estimating true adverse event rates

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Bastien Boussat ◽  
Hude Quan ◽  
Jose Labarere ◽  
Danielle Southern ◽  
Chantal M Couris ◽  
...  
Keyword(s):  
Adverse Event ◽  
Poor Quality ◽  
Report Cards ◽  
Hospital Level ◽  
Quality Of Data ◽  
Imperfect Data ◽  
Data Validity ◽  
The Difference ◽  
Event Rates

Abstract Question Are there ways to mitigate the challenges associated with imperfect data validity in Patient Safety Indicator (PSI) report cards? Findings Applying a methodological framework on simulated PSI report card data, we compare the adjusted PSI rates of three hospitals with variable quality of data and coding. This framework combines (i) a measure of PSI rates using existing algorithms; (ii) a medical record review on a small random sample of charts to produce a measure of hospital-specific data validity and (iii) a simple Bayesian calculation to derive estimated true PSI rates. For example, the estimated true PSI rate, for a theoretical hospital with a moderately good quality of coding, could be three times as high as the measured rate (for example, 1.4% rather than 0.5%). For a theoretical hospital with relatively poor quality of coding, the difference could be 50-fold (for example, 5.0% rather than 0.1%). Meaning Combining a medical chart review on a limited number of medical charts at the hospital level creates an approach to producing health system report cards with estimates of true hospital-level adverse event rates.

Research on Fabric Image Acquisition Based on Compressed Sensing

2014 ◽  
Vol 989-994 ◽  
pp. 3698-3701
Author(s):  
Ji Cheng Dong ◽  
Sheng Qi Guan ◽  
Long Long Chen
Keyword(s):  
Theoretical Analysis ◽  
Compressed Sensing ◽  
Textile Industry ◽  
Image Acquisition ◽  
Sampling Rate ◽  
Image Data ◽  
Sampling Theorem ◽  
High Quality ◽  
Shannon’S Sampling Theorem

Amount of data in collecting data of fabric image in the textile industry put forward a new challenge to sensor end. Compressed Sensing (CS) breaks limit of conventional Shannon’s sampling theorem, so we can reconstruct a signal in Sub-sampling rate. In addition, theoretical analysis tells us that collecting the fabric image data by CS method have a better advantage than collecting the general image data. Having reconstructed three fabric images and one general image by CS method, we can easily find that the former have a high quality of reconstruction.

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