Real-Time Mosaic Method of Aerial Video Based on Two-Stage Key Frame Selection Method

A two-stage automatic key frame selection method is proposed to enhance stitching speed and quality for UAV aerial videos. In the first stage, to reduce redundancy, the overlapping rate of the UAV aerial video sequence within the sampling period is calculated. Lagrange interpolation is used to fit the overlapping rate curve of the sequence. An empirical threshold for the overlapping rate is then applied to filter candidate key frames from the sequence. In the second stage, the principle of minimizing remapping spots is used to dynamically adjust and determine the final key frame close to the candidate key frames. Comparative experiments show that the proposed method significantly improves stitching speed and accuracy by more than 40%.

Rate Control Algorithm of Wireless Video Based on Visual Saliency Map Model

In order to further improve the efficiency of video compression, we introduce a perceptual characteristics of Human Visual System (HVS) to video coding, and propose a novel video coding rate control algorithm based on human visual saliency model in H.264/AVC. Firstly, we modifie Itti's saliency model. Secondly, target bits of each frame are allocated through the correlation of saliency region between the current and previous frame, and the complexity of each MB is modified through the saliency value and its Mean Absolute Difference (MAD) value. Lastly, the algorithm was implemented in JVT JM12.2. Simulation results show that, comparing with traditional rate control algorithm, the proposed one can reduce the coding bit rate and improve the reconstructed video subjective quality, especially for visual saliency region. It is very suitable for wireless video transmission.

Joint routing and rate allocation for multiple video streams in ad-hoc wireless networks

The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.

New Rate Allocation Method for MPEG-4 FGS Video Streaming

A new rate allocation method for fine-granular scalability (FGS) coded bitstreams is presented in order to achieve smooth quality reconstruction of frames under channel conditions with a wide range of bandwidth variation and improve the average PSNR of the whole sequence. Based on a quality weighted bit allocation method, a sliding window rate allocation method is proposed for the first time so that the window can slide along the video sequence with a certain sliding step. Experimental results show that, under dynamic bandwidth conditions, the proposed method can simultaneously satisfy the requirements for improving average PSNR of the whole video sequence greatly and reducing the fluctuations between adjacent frames greatly.

AVariablebitrateVideoCodingSchemeBasedonMorphologicalOperationsforATMNetworks

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Very Low Bit-Rate Video Coding Based on Wavelet Transform

Two video coding schemes based on wavelet transform achieving very low bit rate are presented in this paper. The first is a hybrid motion compensated wavelet transform(MC WT)system which behaves better at very low bit rates than the block DCT residual coder. The second is a new efficient coding system based on a simple frame differencing wavelet transform(FD WT)which performs well in both PSNR and visual quality with substantially reduced complexity.

Variable Bit Rate Fuzzy Control for Low Delay Video Coding

Rate control plays a critical role in achieving perceivable video quality under a variable bit rate,limited buffer sizes and low delay applications.Since a rate control system exhibits non-linear and unpredictable characteristics,it is difficult to establish a very accurate rate-distortion(R-D)model and acquire effective rate control performance.Considering the excellent control ability and low computing complexity of the fuzzy logic in non-linear systems,this paper proposes a bitrate control algorithm based on a fuzzy controller,named the Fuzzy Rate Control Algorithm(FRCA),for All-Intra(AI)and low-delay(LD)video source coding.Contributions of the proposed FRCA mainly consist of four aspects.First,fuzzy logic is adopted to minimize the deviation between the actual and the target buffer size in the hypothetical reference decoder(HRD).Second,a fast lookup table is employed in fuzzy rate control,which reduces computing cost of the control process.Third,an input domain determination scheme is proposed to improve the precision of the fuzzy controller.Fourth,a novel scene change detection is introduced and integrated in the FRCA to adaptively adjust the Group-of-Pictures(GOP)length when the source content fluctuates.The FRCA can be transplanted and implemented in various industry coders.Extensive experiments show that the FRCA has accurate variable bit-rate control ability and maintains a steady buffer size during the encoding processes.Compared with the default configuration encoding under AI and LD,the proposed FRCA can achieve the target bit rates more accurately in various classical encoders.

A NOVEL CROSS-LAYER STRATEGY OF VIDEO TRANSMISSION TO SOLVE PERFORMANCE ANOMALY IN MULTI-RATE IEEE 802.11 NETWORKS

When wireless hosts use different rates to transmit data in IEEE 802.11 networks, it will take on the state of performance anomaly which will severely decrease the throughputs of all the higher rate hosts. Hence, it is bad for video service transmission. Considering that video is very sensitive to packet delivery delay but can tolerate some packet losses, we propose a novel cross-layer scheme which takes these two characteristics into consideration. Firstly, the maximum number of retransmissions for a video Medium Access Control (MAC) frame is computed in MAC layer according to video frame rate requirement of application layer and current access delay of MAC layer. Secondly, within the margin of the tolerant Packet Loss Rate (PLR) of application layer, several video MAC frames are allowed to drop so that we can adaptively select the transmission rate as high as possible for the rest of video MAC frames in terms of current channel quality and the maximum number of retransmissions. Experiment results show that the proposed method can reduce the delay and jitter of video service and improve the throughputs of fast hosts. Therefore, it increases the quality of reconstructed video to a certain extent and relieves the performance anomaly of network effectively.

VBR WAVELET VIDEO CODING AND ITS RATE CONTROL IN ATM NETWORKS

This paper presents a new video coding system based on wavelet transform and its rate control scheme over ATM networks. First, three dimensional wavelet transform is performed for the original image sequence, and an extension of set partitioning in hierarchical trees algorithm is employed to quantize the wavelet coefficients. Then, the output rate of the coder is controlled at group of frame scale, ensuring that it conforms to the parameters of a leaky bucket controller. Several leaky buckets with different sizes are discussed too. Simulation shows the efficiency of this codec and the effectiveness of the proposed rate control scheme.

Rate-distortion optimized frame dropping and scheduling for multi-user conversational and streaming video

We propose a Rate-Distortion (RD) optimized strategy for frame-dropping and scheduling of multi-user conversa- tional and streaming videos. We consider a scenario where conversational and streaming videos share the forwarding resources at a network node. Two buffers are setup on the node to temporarily store the packets for these two types of video applications. For streaming video, a big buffer is used as the associated delay constraint of the application is moderate and a very small buffer is used for conversational video to ensure that the forwarding delay of every packet is limited. A scheduler is located behind these two buffers that dynamically assigns transmission slots on the outgoing link to the two buffers. Rate-distortion side information is used to perform RD-optimized frame dropping in case of node overload. Sharing the data rate on the outgoing link between the con- versational and the streaming videos is done either based on the fullness of the two associated buffers or on the mean incoming rates of the respective videos. Simulation results showed that our proposed RD-optimized frame dropping and scheduling ap- proach provides significant improvements in performance over the popular priority-based random dropping (PRD) technique.

Optimal source rate control for adapting VBR video over CBR channels

In this paper we discuss the source rate control problem of adapting variable bit-rate （VBR） compressed video over constant bit-rate （CBR） channels. Firstly we formulate it as an optimal control problem of a discrete linear system with state and control constraints. Then we apply the discrete maximum principle to get the optimal solution. Experimental results are given in the end. Compared with traditional algorithms, the proposed algorithm is suitable for the coder with continuous output rates, and can achieve the better solution. Our algorithm can be used in both off-line and on-line coding.

Joint Rate Allocation and Buffer Management for Robust Transmission of VBR Video

在这份报纸我们在场在接收装置与播放调整机制在来源集成率分配和缓冲区控制的一个适应录像传播框架。传播率被使用在录像流嵌入以一个精制方法调整传播率的程序钟引用(PCR ) 的一个率分配算法决定。服务者方面也维持多重缓冲区让一些不同重要性层次根据来源缓冲区尺寸，视觉影响，和播放截止时间为控制损失做贸易离开随机的损失。在边界上播放调整机制基于 proportional-integra (PI ) ，控制器在接收装置被采用根据全面损失和接收装置缓冲区占有最大化显示的录像的视觉质量。我们的建议框架的表演在模拟以山峰 signal-to-noise 比率(PSNR ) 被评估，并且模拟结果象译码的框架的更好的质量一样表明平均 PSNR 价值的改进。

3-D Wavelet Transform for Very Low Bit-Rate Video Coding

A new improved Goh's 3 D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3 D WT coding methods and the 2 D WT based coding methods. The new 3 D WT coding scheme is suitable for very low bit rate video coding.

Very Low Bit Rate Video Coding Using Motion Compensated 3 D Wavelet Transform

A new motion compensated 3 D wavelet transform (MC 3DWT) video coding scheme is presented in this paper. The new coding scheme has a good performance in average PSNR, compression ratio and visual quality of reconstructions compared with the existing 3 D wavelet transform (3DWT) coding methods and motion compensated 2 D wavelet transform (MC WT) coding method. The new MC 3DWT coding scheme is suitable for very low bit rate video coding.

The Change in Pulse Rate and Behavioral Score by Using Video Assisted Induction of Pediatric Anesthesia

Purpose: Objective of this study was to determine whether video assisted anesthesia induction reduced pediatric patients’ stress. Methods: With approval from the local ethics committee and parental informed consent, 75 children undergoing minor surgery were investigated in this prospective observational study. Patients were divided into three groups: group 1 was aged two to three years old, group 2 was aged four to six years old and group 3 was aged from seven to ten years old. The following three characteristics were evaluated: 1) the pulse rate at four points (the ward, the entrance at the operating room, mask notification and the mask fit);2) the behavioral score in the operating room;3) the amount of pain killers after the operation. Results: In group 1 (N = 20), there was a significant difference between the control group and the video assisted group regarding the percentage change in pulse rate based on the children’s ward when the patients looked at the mask. In group 2 (N = 26), there was no significant difference regarding any points. In group 3 (N = 29), there was a significant difference between control and video assisted group regarding the percentage change in pulse rate based on the children’s ward for all points. Also, regarding to the behavioral score, there was a significant difference between the control group and the video assisted group of all ages. However, there was no significant difference regarding the use of NSAIDs in the postoperative period between the control and the video assisted group. Conclusion: These results show that the video assisted anesthesia induction is effective for pediatric patients.

Efficient Rate Control Algorithm for Hierarchical Video Coding

For rate control (RC) of hierarchical structure coding, an independent rate-quantization (R-Q) model was proposed based on mean absolute differences (MADs) in different temporal levels (TLs). In the proposed R-Q model, a novel MAD model was developed according to the hierarchical structure. The experimental results demonstrate that the proposed algorithm provides better performance, in terms of average peak signal-to-noise ratio (PSNR) and quality smoothness, than the H.264 reference model, JM14.2, under various sequences.

视频节点式健康教育在体外受精-胚胎移植宣教中的应用效果

目的探讨健康教育视频在体外受精-胚胎移植(IVF-ET)全程健康教育中的应用效果。方法将行IVF-ET治疗的106例患者按照入院时间顺序进行分组。2022年5月至2022年12月纳入的53例为对照组,治疗全过程接受常规健康教育;2023年1月至2023年5月纳入的53例为观察组,治疗全程接受集中观看健康教育视频的方法。对比两组的IVF-ET相关健康知识知晓率、患者满意率及负面情绪。结果干预后,观察组IVF-ET相关健康知识知晓率和患者满意率均高于对照组,焦虑及抑郁程度低于对照组(均P<0.05)。结论视频宣教应用于IVF-ET患者各个治疗节点的健康教育中,有助于患者掌握疾病治疗的相关健康知识,并能提高患者的满意率,能有效缓解患者术前紧张、焦虑的情绪,值得进一步应用。

短视频消费时长能够反映就业率吗?

鉴于现行就业统计方式不能及时、准确反映经济运行形势,如何利用大数据对现有统计指标进行补充成为一个重要问题。鉴于短视频消费已经成为当今社会主要的休闲娱乐方式,文章将短视频消费纳入效用函数,通过失业人员与雇员在时间分配上的差异,揭示全社会用于观看短视频的时间与就业率之间存在的理论联系。通过计量分析,研究发现基于抖音在线人数计算的估计值与描述失业者寻找工作行为的百度搜索指数呈现正相关关系,可以借助短视频观看时长变动说明失业者寻找工作行为的变化。基于抖音在线人数估计的劳动参与率与16—24岁城镇调查失业率存在显著负相关关系,两者的皮尔逊相关系数为-0.862,因此估计的劳动参与率可以作为城镇调查失业率,特别是16—24岁劳动力调查失业率的补充。

全景视频基于块的视口自适应传输方案综述

全景视频由于独特的沉浸式、交互式体验受到广泛关注。全景视频传输所需的高带宽、低时延给现有网络传输系统带来了挑战。基于tile(块)的视口自适应传输可以有效缓解全景视频所带来的传输压力,成为当前的主流方案和研究热点。通过分析基于tile的视口自适应传输方案的研究现状和发展趋势,对该传输方案的两个重要模块,即视口预测与码率分配进行论述,从不同视角归纳总结相关领域的方法。首先,基于全景视频传输框架对相关技术进行阐明;其次,从主、客观两个维度分别介绍评估传输系统性能的用户体验质量的指标;再后,分别从视口预测、码率分配两方面进行归纳,系统梳理经典的研究方法;最后,基于当前研究现状讨论全景视频传输的未来发展趋势。

头戴式手术录像系统在游离皮瓣修复重建手术教学中的应用

目的探讨头戴式手术录像系统应用于游离皮瓣修复重建手术的教学效果。方法纳入2022年6月至2023年12月在上海第九人民医院整复外科进行进修学习的进修医生45名,随机分为试验组(n=23)和对照组(n=22)。两组均采用术前小讲课教授基础理论知识和手术步骤。手术内容上试验组通过手术录像观摩,录像直接取自手术者的头戴式录像装置并配以解说,而对照组采用传统室内手术观摩的方式。比较两组学员的基本理论考核、手术步骤考核成绩和教学满意率。结果试验组手术步骤考核成绩和教学满意率均高于对照组,差异有统计学意义(P<0.05),而基本理论考核成绩两组差异无统计学意义(P>0.05)。结论头戴式微型摄像系统教学能明显提高学员对于皮瓣重建手术的学习效果并提升教学满意度,具有一定的推广意义。