Three-dimensional Coding Research Articles

Fast Color Image Encryption Algorithm Based on DNA Coding and Multi-Chaotic Systems

At present, there is a growing emphasis on safeguarding image data, yet conventional encryption methods are full of numerous limitations. In order to tackle the limitations of conventional color image encryption methodologies, such as inefficiency and insufficient security, this paper designs an expedited encryption method for color images that uses DNA coding in conjunction with multiple chaotic systems. The encryption algorithm proposed in this paper is based on three-dimensional permutation, global scrambling, one-dimensional diffusion and DNA coding. First of all, the encryption algorithm uses three-dimensional permutation algorithms to scramble the image, which disrupts the high correlation among the image pixels. Second, the RSA algorithm and the SHA-256 hashing algorithm are utilized to derive the starting value necessary for the chaotic system to produce the key. Third, the image is encrypted by using global scrambling and one-dimensional diffusion. Finally, DNA coding rules are used to perform DNA computing. The experimental results indicate that the encryption scheme exhibits a relatively weak inter-pixel correlation, uniform histogram distribution, and an information entropy value approaching eight. This shows that the proposed algorithm is able to protect the image safely and efficiently.

A novel color image encryption method based on new three-dimensional chaotic mapping and DNA coding

A novel color image encryption method based on new three-dimensional chaotic mapping and DNA coding

Fast Depth Map Coding Algorithm for 3D-HEVC Based on Gradient Boosting Machine

Three-Dimensional High-Efficiency Video Coding (3D-HEVC) has been extensively researched due to its efficient compression and deep image representation, but encoding complexity continues to pose a difficulty. This is mainly attributed to redundancy in the coding unit (CU) recursive partitioning process and rate–distortion (RD) cost calculation, resulting in a complex encoding process. Therefore, enhancing encoding efficiency and reducing redundant computations are key objectives for optimizing 3D-HEVC. This paper introduces a fast-encoding method for 3D-HEVC, comprising an adaptive CU partitioning algorithm and a rapid rate–distortion-optimization (RDO) algorithm. Based on the ALV features extracted from each coding unit, a Gradient Boosting Machine (GBM) model is constructed to obtain the corresponding CU thresholds. These thresholds are compared with the ALV to further decide whether to continue dividing the coding unit. The RDO algorithm is used to optimize the RD cost calculation process, selecting the optimal prediction mode as much as possible. The simulation results show that this method saves 52.49% of complexity while ensuring good video quality.

Application of Three-dimensional Coding Network in Screening and Diagnosis of Cervical Precancerous Lesions

Globally, the incidence of cervical cancer ranks fourth among female malignant tumors, seriously threatening the physical and mental health of women. Early detection and early treatment can greatly reduce the mortality of cervical cancer "cytology /HPV test, colposcopy and cervical biopsy" is the main method for clinical diagnosis of cervical cancer. The progress of medical technology has significantly improved the early diagnosis of cervical cancer, but due to various factors, there are still many cases of missed diagnosis and misdiagnosis. In recent years, artificial intelligence has developed rapidly in the medical field, and has also shown good applicability in the screening and diagnosis of cervical cancer. In this paper, we design an mcs-SEM structure that contains both channels and space compression excitation modules, which can retain comprehensive spatial information at a low computational cost. Then, the structure is embedded in a three-dimensional coding network to realize the combination of two-dimensional convolutional neural network and three-dimensional spatial information, so as to predict the DVH in the complex distribution scenario of multi-endangered organs with higher accuracy.

Monocular Three-Dimensional Coding Imaging Based on Double Helix Phase Mask

Monocular Three-Dimensional Coding Imaging Based on Double Helix Phase Mask

Photo-induced multi-color fluorescent hydrogels for optical information coding and encryption

In this study, we proposed a method to prepare multi-color fluorescent hydrogels with polyvinyl alcohol (PVA) as the cross-linking network and 7-(6-carboxylpentoxy)-4-methylcoumarin (CPMC), N-ethoxyhexanoate-3,3-dimethyl-6-nitro-indolinspiropyran (SPCOOH) and 2′,7′-dichlorofluorescein (DCF) were introduced to the system. Due to the hydroxyl group in PVA can form a reversible borate bond with borax, the hydrogel could be combined with each other through this chemical bond, thus hydrogels possess reversible cross-linking property and programmable property. The introduction of CPMC, SPCOOH and DCF into the hydrogel could give the hydrogel different photo-response properties. Under UV light irradiation, PVA-CPMC, PVA-CPMC/DCF, PVA-SPCOOH and PVA/DCF hydrogels could emit blue, cyan, pink purple and green fluorescence respectively. In addition, PVA/DCF and PVA-CPMC/DCF hydrogels could emit green fluorescence under 505 nm light irradiation. Based on the various properties of hydrogels, we respectively demonstrated the application of hydrogels in the fields of two-dimensional information encryption, three-dimensional information encryption, three-dimensional information coding and anti-counterfeiting, which can achieve the expected results. Therefore, multi-color fluorescent hydrogels may have potential applications in information encryption, information coding, flexible display and other fields.

Fast 3D‐HEVC inter coding using data mining and machine learning

The Three-Dimensional High Efficiency Video Coding standard is a video compression standard developed based on the two-dimensional video coding standard HEVC and used to encode multi-view plus depth format video. This paper proposes an algorithm based on eXtreme Gradient Boosting to solve the problem of high inter-frame coding complexity in 3D-HEVC. Firstly, explore the correlation between the division depth of the inter-frame coding unit and the texture features in the map, as well as the correlation between the coding unit division structure between each map and each viewpoint. After that, based on the machine learning method, a fast selection mechanism for dividing the depth range of the inter-frame coding tree unit based on the eXtreme Gradient Boosting algorithm is constructed. Experimental results show that, compared with the reference software HTM-16.0, this method can save an average of 35.06% of the coding time, with negligible degradation in terms of coding performance. In addition, the proposed algorithm has achieved different degrees of improvement in coding performance compared with the related works.

Experimental and numerical studies of brittle rock-like specimens with unfilled cross fissures under uniaxial compression

Unfilled cross fissures are defects that widely exist in natural rock, and their existence has a significant impact on the mechanical behaviour of the rock. To investigate the effects of different fissure cross angles (α) and fissure lengths (Lh and Li) on the macroscopic mechanical behaviour, crack development law, ultimate failure mode and final crack distribution of preflawed rock-like specimens, four groups of rock-like material specimens with unfilled cross fissures are fabricated and subjected to uniaxial compression tests using digital image correlation (DIC) technology monitoring, computerized tomography (CT) scanning, and three-dimensional particle coding (PFC3D). These results reveal that the uniaxial compression strength (UCS) and elastic modulus (E) of the specimens all show a nonlinear increase–decrease-increase changing law with increasing α and are all weakened to a certain extent. However, the peak strain (εf) of the specimens shows a nonlinear decrease-increase changing law with increasing α. Based on DIC technology, the influence of α and Lh and Li on the crack development law can be observed. These three parameters mainly affect the crack initiation location of all specimens, and two kinds of ultimate failure modes (shear-tensile mode and tensile mode) can be observed. Based on CT scanning and PFC3D numerical simulation, it can be seen that the final crack system inside the specimen is a 3D system, and the analytical method used to analyse it should contain 2D (DIC technology) and 3D aspects (CT scanning and PFC3D simulation) at the same time.

Genetic Algorithm With Three-Dimensional Population Dominance Strategy for University Course Timetabling Problem

In recent years, with the growing expansion of the recruitment scale and the further reform in teaching, how to use the limited teacher resources and the limited classroom resources to schedule a reasonable university course timetable has gotten great interest. In this paper, the authors firstly hashed over the university course timetabling problem, and then they presented the related mathematical model and constructed the relevant solution framework. Subsequently, in view of characteristics of the university course timetabling problem, they introduced genetic algorithm to solve the university course timetabling problem and proposed many improvement strategies which include the three-dimensional coding strategy, the fitness function design strategy, the initial population generation strategy, the population dominance strategy, the adaptive crossover probability strategy, and the adaptive mutation probability strategy to optimize genetic algorithm. Simulation results show that the proposed genetic algorithm can solve the university course timetabling problem effectively.

Automatic Detection of Pulmonary Nodules using Three-dimensional Chain Coding and Optimized Random Forest

The detection of pulmonary nodules on computed tomography scans provides a clue for the early diagnosis of lung cancer. Manual detection mandates a heavy radiological workload as it identifies nodules slice-by-slice. This paper presents a fully automated nodule detection with three significant contributions. First, an automated seeded region growing is designed to segment the lung regions from the tomography scans. Second, a three-dimensional chain code algorithm is implemented to refine the border of the segmented lungs. Lastly, nodules inside the lungs are detected using an optimized random forest classifier. The experiments for our proposed detection are conducted using 888 scans from a public dataset, and achieves a favorable result of 93.11% accuracy, 94.86% sensitivity, and 91.37% specificity, with only 0.0863 false positives per exam.

Convolution Neural Network-Based Prediction of Protein Thermostability.

Most natural proteins exhibit poor thermostability, which limits their industrial application. Computer-aided rational design is an efficient purpose-oriented method that can improve protein thermostability. Numerous machine-learning-based methods have been designed to predict the changes in protein thermostability induced by mutations. However, all of these methods have certain limitations due to existing mutation coding methods that overlook protein sequence features. Here we propose a method to predict protein thermostability using convolutional neural networks based on an in-depth study of thermostability-related protein properties. This method comprises a three-dimensional coding algorithm, including protein mutation information and a strategy to extract neighboring features at protein mutation sites based on multiscale convolution. The accuracies on the S1615 and S388 data sets, which are widely used for protein thermostability predictions, reached 86.4 and 87%, respectively. The Matthews correlation coefficient was nearly double those produced using other methods. Furthermore, a model was constructed to predict the thermostability of Rhizomucor miehei lipase mutants based on the S3661 data set, a single amino acid mutation data set screened from the ProTherm protein thermodynamics database. Compared with the RIF strategy, which consists of three algorithms, i.e., Rosetta ddg monomer, I Mutant 3.0, and FoldX, the accuracy of the proposed method was higher (75.0 vs 66.7%), and the negative sample resolution was simultaneously enhanced. These results indicate that our prediction method more effectively assessed the protein thermostability and distinguished its features, making it a powerful tool to devise mutations that enhance the thermostability of proteins, particularly enzymes.

Multichannel audio steganography based on MPEG surround using direct sequence spread spectrum

Audio steganography is a technique for embedding hidden message on the audio signal. Several techniques are currently available, proposed as methods to hide secret messages on audio signals and integrated into the audio encoding system. In this paper, a data hiding technique is proposed working based on MPEG Surround (MPS), a multichannel audio encoding standard that is very popular for spatial or three-dimensional (3D) audio coding. Direct sequence spread spectrum (DSSS) is integrated with MPS to embed a secret message into the downmix signal of multichannel audio that generated from MPS encoder. The result of experiments shows that the audio that produced by the proposed system is still in acceptable quality and signal synchronization can run smoothly. The mean value of the signal to noise ratio (SNR) of the audio signal is 16.67 dB. The secret message can be successfully extracted with a mean value of bit error rate (BER) of 3.38%, and normalized correlation (NC) is 95%.

Tunable Duplex Metalens Based on Phase-Change Materials in Communication Range.

Metalenses recently have attracted attention because of their more compact size in comparison with conventional lenses; they can also achieve better optical performance with higher resolution. Duplexer is an interesting function of a metalens that can distinguish different sources and divide them into two parts for specific purposes. In this article, we design tunable duplex metalenses with phase-change material Ge2Sb2Te5 for the first time. Two types of special unit cells are designed to modulate the incident lights, and four metalenses are designed based on the two types of unit cells. Specific phase profiles are calculated for different sections of metalens in which the corresponding unit cells are settled; accordingly, the metalenses can focus the incident lights at any positions according to our design. Moreover, the metalenses become selectable via tuning the state of phase-change material, which means that the output light field can be actively controlled. The proposal of our tunable duplex metalenses will offer new opportunities for active three-dimensional imaging or optical coding.

Security of 3D-HEVC transmission based on fusion and watermarking techniques

This paper presents two robust hybrid watermarking techniques for efficiently securing the transmission of the Three-Dimensional High Efficiency Video Coding (3D-HEVC). The first watermarking technique is the homomorphic-transform-based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The second technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. The objective of the two proposed hybrid watermarking techniques is to increase the immunity of the watermarked 3D-HEVC to attacks and achieve adequate perceptual quality. Also, we propose a wavelet-based fusion technique to combine multiple depth watermark frames into one fused depth watermark frame. Then, the resultant fused depth watermark is embedded in the 3D-HEVC color frames using the two proposed watermarking techniques to produce the watermarked 3D-HEVC streams. The proposed techniques reduce the required bit rate for transmitting the color-plus-depth 3D-HEVC data. The performances of the two proposed watermarking techniques are compared with those of the state-of-the-art watermarking techniques. The comparisons depend on both subjective visual results and objective results: the Peak Signal-to-Noise Ratios (PSNRs) of the watermarked frames and the Normalized Correlation (NC) of the extracted watermark frames. Extensive simulation experiments on different standard 3D video sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed watermarking techniques achieve not only very good perceptual quality, appreciated PSNR values, and saving of the transmission bit rate, but also high correlation coefficients, and high robustness in the presence of attacks. Furthermore, the proposed techniques improve both the capacity of the embedded information and the robustness without affecting the perceptual quality of the original 3D-HEVC frames. Indeed, the extraction of the fused and multiple primary and secondary depth watermark frames is possible in the presence of different attacks.

CART-based fast CU size decision and mode decision algorithm for 3D-HEVC

Despite three-dimensional high efficiency video coding (3D-HEVC) has a good performance of 3D video coding and synthesized views, the recursive splitting process of the largest coding unit (LCU) and the best mode deciding process caused huge computational complexity. To reduce this computational burden, this paper presents a classification and regression tree-based (CART) fast coding level decision and mode decision algorithm for 3D depth video. The algorithm contained two parts: CART model training, fast coding level and mode decision. In the part of CART model training, we constructed a CART decision tree, where the complexity of depth map, the optimal depth level of co-located texture and the relativity of neighbor LCU were regarded as feature vectors, and the best coding unit depth level was regarded as class label. In the part of fast coding process, features were extracted to predict the depth level of each LCU of depth map; furthermore, some decision of coding mode could be skipped early. Experimental results show that proposed algorithm can save the times of coding process by 24.6% on average while maintaining almost the same rate distortion performance as the 3D-HEVC reference software.

Efficient multi-level security for robust 3D color-plus-depth HEVC

This paper presents two robust hybrid watermarking techniques for securing the Three-Dimensional High Efficiency Video Coding (3D-HEVC). The first watermarking technique is the homomorphic-transform-based Singular Value Decomposition (SVD) in Discrete Wavelet Transform (DWT) domain. The second watermarking technique is the three-level Discrete Stationary Wavelet Transform (DSWT) in Discrete Cosine Transform (DCT) domain. The objective of the two proposed hybrid watermarking techniques is to increase the immunity of the watermarked 3D-HEVC streams to attacks. Also, we propose a wavelet-based fusion technique to combine two depth watermark frames into one fused depth watermark frame. Then, the resultant fused depth watermark is encrypted using chaotic Baker map to increase the level of security. After that, the resultant chaotic encrypted fused depth watermark is embedded in the 3D-HEVC color frames using the proposed hybrid watermarking techniques to produce the watermarked 3D-HEVC streams. In addition to achieving multi-level security in the transmitted 3D-HEVC streams, the proposed hybrid techniques reduce the required bit rate for transmitting the color-plus-depth 3D-HEVC data over limited-bandwidth networks. The performance of the proposed hybrid techniques is compared with those of the state-of-the-art techniques. Extensive simulation results on standard 3D video sequences have been conducted in the presence of attacks. The obtained results confirm that the proposed hybrid fusion-encryption-watermarking techniques achieve not only a good perceptual quality with high Peak Signal-to-Noise Ratio (PSNR) values and less bit rate, but also high correlation coefficient values between the original and extracted watermarks in the presence of attacks. Furthermore, the proposed hybrid techniques improve the capacity of information embedding and the robustness without affecting the perceptual quality of the original 3D-HEVC frames. Indeed, the extraction of the encrypted, fused, primary, and secondary depth watermark frames is possible in the presence of attacks.

Block-level fast coding scheme for depth maps in three-dimensional high efficiency video coding

A block-level fast coding scheme for depth maps coding in 3D-high efficiency video coding (3D-HEVC) is presented. The proposed scheme uses the information of the correlated texture coding unit (CU) to accelerate the encoding depth map CU. The experimental analysis demonstrates that when the SKIP mode encodes the texture CU, the current depth map CU has a high probability of being encoded by SKIP or depth intraskip mode. Therefore, the evaluation of the remaining encoding modes can be skipped when any of these modes obtained a low rate-distortion cost. Experimental results obtained through 3D-HEVC test model 16.0 report that our scheme reduces the encoding time by 26.9% with encoding efficiency losses lower than 0.3%.

Improved Depth-Assisted Error Concealment Algorithm for 3D Video Transmission

In this paper, a whole frame loss error concealment algorithm for three-dimensional video coding is proposed. The main concept of the proposed algorithm is to extrapolate the motion vectors for concealing a current error block by jointly considering the available motion vector and the depth information. In addition, the depth information is adopted to help the derivation of reference pixels for concealing errors in the case that suitable motion vectors cannot be obtained by the motion vector extrapolation process alone. Simulation results demonstrate that our proposed algorithm can achieve up to 0.52 dB PSNR, as well as subjective quality improvement, compared to previous work.

Three-Dimensional Adaptive Modulation and Coding for DDO-OFDM Transmission System

We propose a 3-D adaptive loading algorithm (ALA), which can individually allocate proper modulation formats, power levels, and the forward error correction codes to each orthogonal frequency division multiplexing (OFDM) subcarrier according to the estimated channel state information (CSI). The introduced look-up table operation can reduce the iterations and improve the convergence speed. To evaluate the performance of the proposed algorithm, we tailor the system parameters of direct detection optical OFDM (DDO-OFDM) to investigate the difference of effective data rate (EDR) between fixed schemes and proposed adaptive modulation and coding (AMC) schemes. When the fiber length is set to 90 km and received optical power (ROP) is −10 dBm in simulation, the AMC scheme achieves 7.86 Gb/s EDR, which is 1.93 times of the maximum EDR the fixed schemes can achieve under the bit error rate (BER) constraint. Compared with the Levin−Campello algorithm, the 3-D ALA improves about 3% and 6% data rates in poor and good CSI, respectively. In experiments, when the fiber length and ROP are 50 km and −18 dBm, respectively, the AMC scheme achieves the EDR of 4.96 Gb/s, which is 2.84 times of the maximum EDR of the fixed schemes under the BER constraint.

An efficient hardware solution for 3D-HEVC intra-prediction

Three-dimensional high-efficiency video coding (3D-HEVC) is the highest profile extension of HEVC for 3D video coding that supports the advanced 3D video format, multi-view video plus depth (MVD). Depth modelling modes (DMMs) are adopted into 3D-HEVC to preserve sharp edges and avoid ringing artefacts in synthesized views. However, computational complexity increases significantly with these modes. A novel hardware solution that reduces the complexity of DMMs for 3D-HEVC is presented in the present paper. This solution contains five modules working in parallel to find all DMMs defined in the new standard for all depth block sizes (from 4 × 4 to 32 × 32). A new technique for obtaining the most compatible wedgelet pattern with its own syntax is developed to minimize the quantity of calculations coming from DMM1; the aforementioned information (wedgelet pattern and syntax) is already calculated and stored in an external memory. This design is synthesized for a Xilinx Virtex 6 FPGA and can process up to 30 frames per second (FPS) while considering the encoding of 6 full HD views in real time. The proposed solution can reach a processing rate up to 30 FPS for 4 QHD views in real time when using 4K video encoding.