Hezerul Abdul Karim

Scalable multiple description video coding for stereoscopic 3D

Scalable multiple description video coding (MDC) provides adaptability to bandwidth variations and receiving device characteristics, and can improve error robustness in multimedia networks. In this paper, a scalable MDC scheme is proposed for stereoscopic 3D video. Scalable MDC has previously been applied to 2D video but not to 3D video. The proposed algorithm enhances the error resilience of the base layer of the scalable video coding (SVC) standard using even and odd frame based MDC. The performance of the algorithm is evaluated in error free and error prone environments. Simulation results show improved performance using the proposed scalable MDC at high error rates compared to the original SVC. To improve the rate distortion performance, down-sampling of the depth information is proposed for SVC and scalable MDC. The proposed method reduces the overall bit rates and consequently: (1) improves their rate distortion, particularly at lower bit rates in error free channels; and (2) improves their performance in error prone channels.

Scalable multiple description coding with side information using motion interpolation

Problems with modern video delivery systems is that decoder fails to decode video when it is transmitted over error prone channels, due to varying characteristics of a wireless channel or congestion in wired networks. Thus introducing mismatch into the decoded video stream. Scalable video coding (SVC) encounters such a problem as the loss of a lower layer prevents all higher layers being decoded, even if the higher layers are correctly received. Multiple description coding (MDC) can help solve such a problem. We propose a scalable MDC architecture that creates an even and odd streams with residual information regarding the other stream. Using such a method creates redundancies that can improve the decoded reconstruction of a frame however increasing the bit rate of a given stream. To solve this a motion interpolation technique is used to improve the construction of side information thus reducing the bit rate but improving the frame quality. Experimental results show that motion interpolation scheme can improve the frame quality by 6 dB over a pixel based interpolation scheme for a number of video sequences Experimental results also show that this method can give 40% saving in bit rate when compared to a pixel based interpolation. Using such a method makes the system a viable target for mobile communications.

Multiresolution motion estimation for low-rate video frame interpolation

Interpolation of video frames with the purpose of increasing the frame rate requires the estimation of motion in the image so as to interpolate pixels along the path of the objects. In this paper, the specific challenges of low-rate video frame interpolation are illustrated by choosing one well-performing algorithm for high-frame-rate interpolation (Castango 1996) and applying it to low frame rates. The degradation of performance is illustrated by comparing the original algorithm, the algorithm adapted to low frame rate, and simple averaging. To overcome the particular challenges of low-frame-rate interpolation, two algorithms based on multiresolution motion estimation are developed and compared on objective and subjective basis and shown to provide an elegant solution to the specific challenges of low-frame-rate video interpolation.

Depth image-based spatial error concealment for 3-D video transmission

An alternative form of stereoscopic video is the combination of 2-D video from an ordinary 2-D video camera and depth information from a laser range or depth camera. When this type of 3-D video is compressed and transmitted over error prone channels, the associated packet loss leads to poor visual quality. Therefore, a depth image-based error concealment for 3-D video transmission is proposed, which utilizes a strong correlations between 2-D video and its corresponding depth map. The depth information provides an indication of object boundaries to assist the concealment process. This spatial object based error concealment involves concealment decision process and frequency extrapolation.

Multicast Link Adaptation in Reliable Transmission Over Geostationary Satellite Networks

The exploitation of fluctuating channel conditions in link adaption techniques for unicast transmission has been shown to provide large system capacity gains. However, the problem of choosing transmission rates for multicast transmission has not been thoroughly investigated. In this paper, we investigate multicast adaptive techniques for reliable data delivery in GEO satellite networks. An optimal multicast link adaptation is proposed with the aim to maximise terminal throughput whilst increasing resource utilization and fairness in the face of diverse channel conditions. Via simulation results and theoretical analysis, the proposed algorithm has shown to outperform other alternative multicast link adaptation techniques especially when the terminals are in vigorous channel conditions.

Segmentation and compression of pharynx and esophagus fluoroscopic images

Enormous amounts of sequential medical images are produced in modern medical examinations, typically in Fluoroscopy. Although highly effective, such large quantities of images incur a high cost in terms of storage, processing time and transmission. This paper proposes a method for lossless compression of targeted parts within Fluoroscopy images, extracting the region of interest (ROI) - in this case the pharynx and esophagus, and employing customized correlation and the combination of Run Length and Huffman coding, to increase compression efficiency. The experimental results show that the proposed method improved performance with a compression ratio of 300% better than conventional methods.

Scalable video streaming over overlay/underlay cognitive radio network

Cognitive radio (CR) with dynamic spectrum allocation (DSA) allows new or secondary devices to opportunistically access a portion of spectrum, which belongs to primary (licensed) users (PU). This allows the secondary users (SU) to transmit data services when the PUs are not using the spectrum. However, problem arises when SU experiences interrupted services if the PU needs to use the spectrum. The objective of this paper is to provide uninterrupted multimedia data services (video transmission) to SU by allowing the SU to receive data in both the overlay and underlay mode of CR. Since the underlay mode CR is characterized by low power and low data rate, base layer video streaming of a scalable video coding (SVC) is an attractive solution. In overlay mode, the enhancement layers and the base layer of the SVC are streamed without interruptions. The base layer video is protected from video packet loss by using I-frames insertion. Simulation results show that it is a great challenge to transmit video in the underlay CR. Nevertheless, with high protection of the base layer video of the SVC, acceptable video quality can be achieved.

Multiple description video coding for stereoscopic 3D

In this paper, we propose an MDC schemes for stereoscopic 3D video. In the literature, MDC has previously been applied in 2D video but not so much in 3D video. The proposed algorithm enhances the error resilience of the 3D video using the combination of even and odd frame based MDC while retaining good temporal prediction efficiency for video over error-prone networks. Improvements are made to the original even and odd frame MDC scheme by adding a controllable amount of side information to improve frame interpolation at the decoder. The side information is also sent according to the video sequence motion for further improvement. The performance of the proposed algorithms is evaluated in error free and error prone environments especially for wireless channels. Simulation results show improved performance using the proposed MDC at high error rates compared to the single description coding (SDC) and the original even and odd frame MDC.

Low rate video frame interpolation - challenges and solution

The challenges specific to interpolation at low video frame rates are illustrated by choosing an algorithm that performs well at high frame rates and applying it to low frame rates. The performance is illustrated by comparing the original algorithm, the algorithm adapted to low frame rate particularities, and simple averaging. To overcome the particular challenges of low frame rates, two algorithms were developed and compared on objective and subjective bases and shown to provide elegant solutions to the specific challenges of low frame rate video interpolation.

Lossless Compression of Pharynx and Esophagus in Fluoroscopic Medical Images

 Abstract—Hospitals and medical centers produce a tremendous amount of sequential images for medical examinations such as MRI, CT and Fluoroscopy. This series of images takes up a large amount of storage space, in addition to the cost and time incurred during transmission. For medical data, lossless compression is preferable to the greater gains of lossy compression, in the interest of reliability. This paper proposes a new method for lossless compression of pharynx and esophagus fluoroscopy images, depending on correlation and combination of Run Length and Huffman. Otherwise, the shifted images moved to a shifted group and compress separately. From the experimental results obtained, the proposed method achieved improved performance with a compression ratio of 12.2 for the proposed combination of Run-length and Huffman coding (R. Huff) on the difference images as compared to 1.35 for the standard method.