Error resilient video transcoding for robust inter-network communications using GPRS

A novel fully comprehensive mobile video communications system is proposed in this paper. This system exploits the useful rate management features of the video transcoders and combines them with error resilience for transmissions of coded video streams over general packet radio service (GPRS) mobileaccess networks. The error-resilient video transcoding operation takes place at a centralized point, referred to as a video proxy, which provides the necessary output transmission rates with the required amount of robustness. With the use of this proposed algorithm, error resilience can be added to an already compressed video stream at an intermediate stage at the edge of two or more different networks through two resilience schemes, namely the adaptive intra refresh (AIR) and feedback control signaling (FCS) methods. Both resilience tools impose an output rate increase which can also be prevented with the proposed novel technique in this paper. Thus, an error-resilient video transcoding scheme is presented to give robust video outputs at near target transmission rates that only require the same number of GPRS timeslots as the nonresilient schemes. Moreover, an ultimate robustness is also accomplished with the combination of the two resilience algorithms at the video proxy. Extensive computer simulations demonstrate the effectiveness of the proposed system

Scale and Translation Invariant Face Detection and Efficient Facial Feature Extraction

In this paper, improved and fully automatic face detection and facial feature extraction algorithms are introduced. The face detection algorithm is based on skin color, head shape and additional information such as orientation and characteristics of the segmented face region. The proposed face detection technique is position, scale, shape and skin color invariant. The more challenging task of facial feature extraction involves the identification of the sub-images containing the facial features. Each sub-image is analyzed by an efficient combination of a number of techniques such as: circle fitting, edge detection, and intensity based adaptive clustering. Our simulations indicate that the performance especially for the detection of facial features is significantly improved

Kinematic Synthesis of a Tendon-Driven Robotic Arm

This paper deals with the kinematic synthesis of a planar tendon-driven robotic arm to remove skins by wine fermentation tanks, with three d.o.f.s and thus, one time redundant. This redundancy is required in order to obtain a deployable mechanism in the form of robotic arm, which shows a wide workspace, but occupies a small volume when fully flexed. The type and dimensional kinematic synthesis of the proposed robotic arm is developed through a serial combination of endless tendon-driven kinematic chains, which joints are remotely actuated. The synthesis methodology is first applied to a Cardan mechanism, a parallel motion generator, a robotic finger, and then, to the synthesis of the proposed robotic arm with the aim to satisfy the design specifications