Smart selective encryption of H.264/AVC videos using confidentiality metrics

In the field of video protection, selective encryption (SE) is a scheme which ensures the visual security of a video by encrypting only a small part of the data. This paper presents a new SE algorithm for H.264/AVC videos in context-adaptive variable-length coding mode. This algorithm controls the amount of encrypted alternative coefficients (ACs) of the integer transform in the entropic encoder. Two visual quality measures, the peak signal-to-noise ratio (PSNR) and the structural similarity (SSIM), are used to measure the visual confidentiality level of each video frame and to control the amount of encrypted ACs. Moreover, a new psychovisual metric to measure the flickering is introduced, the so-called temporal structural similarity (TSSIM). This method can be applied on intra and inter frame video sequences. Several experimental results show the efficiency of the proposed method.     

Microcomputer-Based Controls for Continuous Casting

The continuous casting of steel eliminates many processing steps, thus allowing savings in time, energy, and processing costs. In this process a moving strand of steel is partially solidified in a water-cooled mold and subsequently cooled to complete solidification by intensive-cooling water sprays. Control of the cooling sprays is complex, requiring distributed control techniques, which are not readily implemented by analog means. Therefore, digital computer control systems have been developed for this purpose. In the past these systems have used a minicomputer in a supervisory control mode to provide optimum water-flow setpoints to conventional proportional plus integral analog controllers. This approach has given satisfactory results, but initial hardware and software costs have been high, and maintenance requirements, particularly in the computer/controller interface hardware, have been excessive. US Steel is currently testing a microcomputer-based control system which has the potential for resolving these problems. This system provides all the control features normally used as well as direct digital control (ddc) of cooling water flows, thus eliminating the need for analog controllers. Experience to date indicates that this new approach will provide increased reliability along with a significant reduction in equipment and maintenance costs.     

硬盘DV是主流不同存储介质DV选择调查报告

数码摄像机按存储介质分类,可分为磁带型、DVD光盘型、硬盘型以及闪存型。消费者更偏爱于哪种类型的数码摄像机呢?从以下的调查结果中可以看到,硬盘型数码摄像机普遍     

选择适合电源应用的IC

从成本、解决方案尺寸、电源、占空比及要求输出功率等许多因素进行权衡,来选择最佳的电源应用IC.针对各输出选择最佳拓扑结构,详细论述了电源设计步骤,大大简化了电源设计.