Showing papers by "Manuel P. Malumbres published in 2007"
TL;DR: The results achieved through simulation show that the proposed QoS framework can perfectly coexist with multipath routing protocols, achieving significant improvements on the overall network performance, especially from the point of view of demanding applications such as real time video and voice applications.
35 citations
28 Sep 2007
TL;DR: This work takes as reference the PSNR metric and tries to find out if there is a more accurate metric in terms of human quality perception that could substitute PSNR in the performance evaluation of different coding proposals under packet loss scenarios.
Abstract: It is well known that PSNR does not always rank quality of an image or video sequence in the same way that a human being. There are many other factors considered by the human visual system and the brain. So, a lot of efforts were required to find an objective video quality metric that is able to measure the quality distortion similarly to the one perceived by the destination user. We analyze the behaviour of some of the most relevant objective quality metrics when they are applied to video compressed by a H264/AVC codec at different bit-rates and with error resilience options enabled. Video data is transmitted in a wireless MANET environment and packet losses are modelled for different scenarios including variable congestion and mobility states. We take as reference the PSNR metric and try to find out if there is a more accurate metric in terms of human quality perception that could substitute PSNR in the performance evaluation of different coding proposals under packet loss scenarios.
26 citations
28 Jan 2007
TL;DR: In this paper, the authors analyze the impact of simple rate control tools for non-embedded wavelet image encoders in order to determine if the inclusion of rate control functionality is worth enough with respect to popular embedded encoder like SPIHT and JPEG2000 in terms of R/D performance, coding delay and memory consumption.
Abstract: Recently, there has been an increasing interest in the design of very fast wavelet image encoders focused on applications (interactive real-time image&video applications, GIS systems, etc) and devices (digital cameras, mobile phones, PDAs, etc) where coding delay and/or available computing resources (working memory and power processing) are critical for proper operation. Most of these fast wavelet image encoders are non-embedded in order to reduce complexity, so no rate control tools are available for scalable coding applications. In this work, we analyze the impact of simple rate control tools for these encoders in order to determine if the inclusion of rate control functionality is worth enough with respect to popular embedded encoders like SPIHT and JPEG2000. We perform the study by adding rate control to the nonembedded LTW encoder, showing that the increase in complexity still maintains LTW competitive with respect SPIHT and JPEG2000 in terms of R/D performance, coding delay and memory consumption.
7 citations
23 Jun 2007
TL;DR: The purpose is to perform a study about the behavior of IEEE 802.11 technology to evaluate if it would be able to comply with the requirements of this application, and to analyze the different components of the overall system, making special emphasis in video coding engines and network response.
Abstract: Delivery of video encoded bitstreams in wireless networks is a challenging task due to different factors (node mobility, time-varying wireless channel, etc.) that put in evidence the lack of QoS support for this kind of applications. In particular, we are working with teleoperated mobile robot systems. Our purpose is to perform a study about the behavior of IEEE 802.11 technology to evaluate if it would be able to comply with the requirements of this application. So, we have developed a prototype that consists of one mobile robot with an onboard webcam and an IEEE 802.11 network adapter. The control station sends navigation commands to the robot and, at the same time, receives a video stream that shows to the user a frontal view of actual robot location. We will analyze the different components of the overall system, making special emphasis in video coding engines and network response.
4 citations
12 Nov 2007
TL;DR: This paper introduces a frame-by-frame algorithm to calculate the 3D-DWT with low memory usage and it can be employed with any wavelet transform and, contrary to other proposals, it gets the same results as the regular wavelets.
Abstract: The 3D-DWT is a mathematical tool of increasing importance. However, the huge memory requirement of the algorithms that compute it is one of the main drawbacks in practical implementations. In this paper, we introduce a frame-by-frame algorithm to calculate the 3D-DWT with low memory usage. This algorithm is general, in the sense that it can be employed with any wavelet transform and, contrary to other proposals, it gets the same results as the regular wavelet transform. In addition, there is no need to divide the input video sequence into group of frames, and it can be applied in a continuous manner, so that coding efficiency is increased and no blocking artifacts appear.
3 citations
11 Dec 2007
TL;DR: This work proposes an intra video codec, M-LTW, which is able to reach very good R/D performance results, as well as JPEG2000 or H.264 INTRA, with faster processing and lower memory usage.
Abstract: Intra video coding is a common way to process video material for applications like professional video editing systems, digital cinema, video surveillance applications, multispectral satellite imaging, HQ video delivery, etc. Most practical intra coding systems employ JPEG encoders due to their simplicity, low coding delay and low memory requirements. JPEG2000 is the main candidate to replace JPEG in this kind of applications due to the excellent R/D performance and high coding flexibility. However, its complexity and computational resources required for proper operation could be a limitation for certain applications. In this work, we propose an intra video codec, M-LTW, which is able to reach very good R/D performance results, as well as JPEG2000 or H.264 INTRA, with faster processing and lower memory usage.
1 citations
01 Jan 2007
TL;DR: In this article, the authors proposed an intra video codec, M-LTW, which is able to reach very good R/D performance results as well as JPEG2000 or H.264 INTRA, with faster processing and lower memory usage.
Abstract: Intra video coding is a common way to process video material for applications like professional video editing systems, digital cinema, video surveillance applications, multispectral satellite imaging, HQ video delivery, etc. Most practical intra coding systems employ JPEG encoders due to their simplicity, low coding delay and low memory requirements. JPEG2000 is the main candidate to replace JPEG in this kind of applications due to the excellent R/D performance and high coding flexibility. However, its complexity and computational resources required for proper operation could be a limitation for certain applications. In this work, we propose an intra video codec, M-LTW, which is able to reach very good R/D performance results, as well as JPEG2000 or H.264 INTRA, with faster processing and lower memory usage.