EDBT 2026 Demo / reviewers in the wild / expert
Ragnar Langseth
dblp:141/6352
· DBLP profile ↗
12ranked-venue papers
1as first author
0since 2021 · last 2018
—ORCID · none
Domains — the database's venue-derived domains; a paper can count in several
Graphics, computer vision, multimedia, augmented reality and games · 11 · 1 first-authorComputer networks · 3
Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.
| Computer graphics and multimedia
2 papers |
Computational photography and imaging · 56% Multimedia analysis and retrieval · 28% Image and video processing · 17% |
Topics — the 4 heaviest of 5, each with the papers that count most for it
| Topic | Weight | Papers | Last | Evidence papers |
|---|---|---|---|---|
Computational photography and imaging
high dynamic range imaging |
0.2 | 1 | 2014 | Real-Time HDR Panorama Video · ACM Multimedia 2014 |
Multimedia analysis and retrieval
object tracking |
0.2 | 1 | 2014 | Automatic Real-Time Zooming and Panning on Salient Objects from a Panoramic Video · ACM Multimedia 2014 |
Computational photography and imaging › image stitching
panoramic image stitching |
0.2 | 1 | 2014 | Real-Time HDR Panorama Video · ACM Multimedia 2014 |
Image and video processing
image enhancement |
0.1 | 1 | 2014 | Real-Time HDR Panorama Video · ACM Multimedia 2014 |
Methods — techniques the papers use, named apart from their topics
multi-camera panorama · 0.2automatic zooming and panning · 0.2HDR video algorithms · 0.2
| Year | Publication | Venue | Position |
|---|---|---|---|
| 2018 | Efficient Live and on-Demand Tiled HEVC 360 VR Video StreamingabstractWith 360° panorama video technology becoming commonplace, the need for efficient streaming methods for such videos arises. We go beyond the existing on-demand solutions and present a live streaming system which strikes a trade-off between bandwidth usage and the video quality in the user’s field-of-view. We have created an architecture that combines RTP and DASH to deliver 360° VR content to a Huawei set-top-box and a Samsung Galaxy S7. Our system multiplexes a single HEVC hardware decoder to provide faster quality switching than at the traditional GOP boundaries. We demonstrate the performance and illustrate the trade-offs through real-world experiments where we can report comparable bandwidth savings to existing on-demand approaches, but with faster quality switches when the field-of-view changes. Mattis Jeppsson, Håvard Espeland, Tomas Kupka, Ragnar Langseth, Andreas Petlund, Peng Qiaoqiao, Chuansong Xue, Konstantin Pogorelov, Michael Riegler 0001, Dag Johansen, Carsten Griwodz, Pål Halvorsen |
ISM | 4 |
| 2015 | Scaling virtual camera services to a large number of usersabstractBy processing video footage from a camera array, one can easily make wide-field-of-view panorama videos. From the single panorama video, one can further generate multiple virtual cameras supporting personalized views to a large number of users based on only the few physical cameras in the array. However, giving personalized services to large numbers of users potentially introduces both bandwidth and processing bottlenecks, depending on where the virtual camera is processed. Vamsidhar Reddy, Ragnar Langseth, Håkon Kvale Stensland, Carsten Griwodz, Pål Halvorsen, Dag Johansen |
MMSys | 2 |
| 2015 | Tiling of panorama video for interactive virtual cameras: Overheads and potential bandwidth requirement reductionabstractDelivering high resolution, high bitrate panorama video to a large number of users introduces huge scaling challenges. To reduce the resource requirement, researchers have earlier proposed tiling in order to deliver different qualities in different spatial parts of the video. In our work, providing an interactive moving virtual camera to each user, tiling may be used to reduce the quality depending on the position of the virtual view. This raises new challenges compared to existing tiling approaches as the need for high quality tiles dynamically change. In this paper, we describe a tiling approach of panorama video for interactive virtual cameras where we provide initial results showing the introduced overheads and the potential reduction in bandwidth requirement. Vamsidhar Reddy, Hoang Bao Ngo, Ragnar Langseth, Carsten Griwodz, Dag Johansen, Pål Halvorsen |
PCS | 3 |
| 2015 | The Cameraman Operating My Virtual Camera is Artificial: Can the Machine Be as Good as a Human?abstractIn this article, we argue that the energy spent in designing autonomous camera control systems is not spent in vain. We present a real-time virtual camera system that can create smooth camera motion. Similar systems are frequently benchmarked with the human operator as the best possible reference; however, we avoid a priori assumptions in our evaluations. Our main question is simply whether we can design algorithms to steer a virtual camera that can compete with the user experience for recordings from an expert operator with several years of experience? In this respect, we present two low-complexity servoing methods that are explored in two user studies. The results from the user studies give a promising answer to the question pursued. Furthermore, all components of the system meet the real-time requirements on commodity hardware. The growing capabilities of both hardware and network in mobile devices give us hope that this system can be deployed to mobile users in the near future. Moreover, the design of the presented system takes into account that services to concurrent users must be supported. Vamsidhar Reddy, Ragnhild Eg, Ragnar Langseth, Carsten Griwodz, Pål Halvorsen |
ACM Trans. Multim. Comput. Commun. Appl. | 3 |
| 2014 | An Evaluation of Debayering Algorithms on GPU for Real-Time Panoramic Video RecordingabstractModern video cameras normally only capture a single color per pixel, commonly arranged in a Bayer pattern. This means that we must restore the missing color channels in the image or the video frame in post-processing, a process referred to as debayering. In a live video scenario, this operation must be performed efficiently in order to output each frame in real-time, while also yielding acceptable visual quality. Here, we evaluate debayering algorithms implemented on a GPU for real-time panoramic video recordings using multiple 2K-resolution cameras. Ragnar Langseth, Vamsidhar Reddy, Håkon Kvale Stensland, Carsten Griwodz, Pål Halvorsen |
ISM | 1 |
| 2014 | Using a Commodity Hardware Video Encoder for Interactive Video StreamingabstractOver the last years, video streaming has become one of the most dominant Internet services. A trend now is that due to the increased availability of high-speed internet access, multimedia services are becoming more interactive and immersive. Examples of such applications are both cloud gaming and systems where users can interact with high-resolution content. Over the last few years, hardware video encoders have been built into commodity hardware. We evaluate one of these encoders in a scenario where we have individual streams delivered to the end users. Our results show that we can reduce almost half of the CPU time spent on video processing, while also greatly reducing the power consumption on the system. We also compare the visual video quality and the frame size of the hardware based encoder, and we find no significant difference compared to a software based approach. Martin Alexander Wilhelmsen, Håkon Kvale Stensland, Vamsidhar Reddy, Asgeir Mortensen, Ragnar Langseth, Carsten Griwodz, Pål Halvorsen |
ISM | 5 |
| 2014 | Automatic Real-Time Zooming and Panning on Salient Objects from a Panoramic VideoabstractThe proposed demo shows how our system automatically zooms and pans into tracked objects in panorama videos. At the conference site, we will set up a two-camera version of the system, generating live panorama videos, where the system zooms and pans tracking people using colored hats. Additionally, using a stored soccer game video from a five 2K camera setup at Alfheim stadium in Tromsø from the European league game between Tromsø IL and Tottenham Hotspurs, the system automatically follows the ball. Vamsidhar Reddy, Ragnar Langseth, Håkon Kvale Stensland, Carsten Griwodz, Pål Halvorsen, Øystein Landsverk |
ACM Multimedia | 2 |
| 2014 | Real-Time HDR Panorama VideoabstractThe interest for wide field of view panorama video is increasing. In this respect, we have an application that uses an array of cameras that overlook a soccer stadium. The input of these cameras are stitched together to provide a panoramic view of the stadium. One of the challenges we face is that large parts of the field are obscured by shadows on sunny days. Such circumstances cause unsatisfying video quality. We have therefore implemented and evaluated multiple algorithms related to high dynamic range (HDR) video. The evaluation shows that a combination of several approaches gives the most useful results in our scenario. Lorenz Kellerer, Vamsidhar Reddy, Ragnar Langseth, Håkon Kvale Stensland, Carsten Griwodz, Dag Johansen, Pål Halvorsen |
ACM Multimedia | 3 |
| 2014 | Be your own cameraman: real-time support for zooming and panning into stored and live panoramic videoabstractHigh-resolution panoramic video with a wide field-of-view is popular in many contexts. However, in many examples, like surveillance and sports, it is often desirable to zoom and pan into the generated video. A challenge in this respect is real-time support, but in this demo, we present an end-to-end real-time panorama system with interactive zoom and panning. Our system installed at Alfheim stadium, a Norwegian premier league soccer team, generates a cylindrical panorama from five 2K cameras live where the perspective is corrected in real-time when presented to the client. This gives a better and more natural zoom compared to existing systems using perspective panoramas and zoom operations using plain crop. Our experimental results indicate that virtual views can be generated far below the frame-rate threshold, i.e., on a GPU, the processing requirement per frame is about 10 milliseconds. Vamsidhar Reddy, Ragnar Langseth, Håkon Kvale Stensland, Pierre Gurdjos, Vincent Charvillat, Carsten Griwodz, Dag Johansen, Pål Halvorsen |
MMSys | 2 |
| 2014 | Soccer video and player position datasetabstractThis paper presents a dataset of body-sensor traces and corresponding videos from several professional soccer games captured in late 2013 at the Alfheim Stadium in Tromsø, Norway. Player data, including field position, heading, and speed are sampled at 20Hz using the highly accurate ZXY Sport Tracking system. Additional per-player statistics, like total distance covered and distance covered in different speed classes, are also included with a 1Hz sampling rate. The provided videos are in high-definition and captured using two stationary camera arrays positioned at an elevated position above the tribune area close to the center of the field. The camera array is configured to cover the entire soccer field, and each camera can be used individually or as a stitched panorama video. This combination of body-sensor data and videos enables computer-vision algorithms for feature extraction, object tracking, background subtraction, and similar, to be tested against the ground truth contained in the sensor traces. Svein Arne Pettersen, Dag Johansen, Håvard D. Johansen, Vegard Berg-Johansen, Vamsidhar Reddy, Asgeir Mortensen, Ragnar Langseth, Carsten Griwodz, Håkon Kvale Stensland, Pål Halvorsen |
MMSys | 7 |
| 2014 | Interactive Zoom and Panning from Live Panoramic VideoabstractPanorama video is becoming increasingly popular, and we present an end-to-end real-time system to interactively zoom and pan into high-resolution panoramic videos. Compared to existing systems using perspective panoramas with cropping, our approach creates a cylindrical panorama. Here, the perspective is corrected in real-time, and the result is a better and more natural zoom. Our experimental results also indicate that such zoomed virtual views can be generated far below the frame-rate threshold. Taking into account recent trends in device development, our approach should be able to scale to a large number of concurrent users in the near future. Vamsidhar Reddy, Ragnar Langseth, Sigurd Ljødal, Pierre Gurdjos, Vincent Charvillat, Carsten Griwodz, Pål Halvorsen |
NOSSDAV | 2 |
| 2014 | Bagadus: An integrated real-time system for soccer analyticsabstractThe importance of winning has increased the role of performance analysis in the sports industry, and this underscores how statistics and technology keep changing the way sports are played. Thus, this is a growing area of interest, both from a computer system view in managing the technical challenges and from a sport performance view in aiding the development of athletes. In this respect, Bagadus is a real-time prototype of a sports analytics application using soccer as a case study. Bagadus integrates a sensor system, a soccer analytics annotations system, and a video processing system using a video camera array. A prototype is currently installed at Alfheim Stadium in Norway, and in this article, we describe how the system can be used in real-time to playback events. The system supports both stitched panorama video and camera switching modes and creates video summaries based on queries to the sensor system. Moreover, we evaluate the system from a systems point of view, benchmarking different approaches, algorithms, and trade-offs, and show how the system runs in real time. Håkon Kvale Stensland, Vamsidhar Reddy, Marius Tennøe, Espen Helgedagsrud, Mikkel Næss, Henrik Kjus Alstad, Asgeir Mortensen, Ragnar Langseth, Sigurd Ljødal, Øystein Landsverk, Carsten Griwodz, Pål Halvorsen, Magnus Stenhaug, Dag Johansen |
ACM Trans. Multim. Comput. Commun. Appl. | 8 |