Adaptive Frame Rate Research Articles

Distributed video transmission reduction approach for energy saving in WMSNs

SummaryWireless Multimedia Sensor Networks (WMSNs) are composed of a large number of sensor nodes that are distributed in a region to collect and transmit data. Video transmission is one of the most important applications of WMSNs because it can provide critical information about monitored areas. WMSNs face challenges related to energy consumption, bandwidth usage, and network congestion related to huge amounts of data collected by sensors. To tackle this problem, this paper proposes the Distributed Video Transmission Reduction Approach for Energy Saving in WMSN (DiViTRA). The method involves two phases: sensing and transmission phases. DiViTRA achieves frame rate adaptation to reduce the number of captured video frames and save energy during the sensing phase. In the transmission phase, three effective techniques, ORB (Oriented FAST and Rotated BRIEF), Brute‐Force (BF) Matcher, and Grid‐based Motion Statistics (GMS) are applied to decide whether to transmit the current captured frame or remove it and adjust the frame capturing rate of the video sensor accordingly. In the case of frame transmission, the DiViTRA approach compresses the frame using two data reduction approaches: PCA (Principal Component Analysis) and Huffman encoding. Through simulations, DiViTRA demonstrates a 12% reduction in energy consumption, and 71% is a ratio of reduction in sent frames while preserving stream quality. The approach has been validated in scenarios involving critical events, showcasing its efficacy in maintaining data integrity during transmission.

A power-aware vision-based virtual sensor for real-time edge computing

Graphics processing units and tensor processing units coupled with tiny machine learning models deployed on edge devices are revolutionizing computer vision and real-time tracking systems. However, edge devices pose tight resource and power constraints. This paper proposes a real-time vision-based virtual sensors paradigm to provide power-aware multi-object tracking at the edge while preserving tracking accuracy and enhancing privacy. We thoroughly describe our proposed system architecture, focusing on the Dynamic Inference Power Manager (DIPM). Our proposed DIPM is based on an adaptive frame rate to provide energy savings. We implement and deploy the virtual sensor and the DIPM on the NVIDIA Jetson Nano edge platform to prove the effectiveness and efficiency of the proposed solution. The results of extensive experiments demonstrate that the proposed virtual sensor can achieve a reduction in energy consumption of about 36% in videos with relatively low dynamicity and about 21% in more dynamic video content while simultaneously maintaining tracking accuracy within a range of less than 1.2%.

Joint frame rate adaptation and object recognition model selection for stabilized unmanned aerial vehicle surveillance

AbstractWe propose an adaptive unmanned aerial vehicle (UAV)‐assisted object recognition algorithm for urban surveillance scenarios. For UAV‐assisted surveillance, UAVs are equipped with learning‐based object recognition models and can collect surveillance image data. However, owing to the limitations of UAVs regarding power and computational resources, adaptive control must be performed accordingly. Therefore, we introduce a self‐adaptive control strategy to maximize the time‐averaged recognition performance subject to stability through a formulation based on Lyapunov optimization. Results from performance evaluations on real‐world data demonstrate that the proposed algorithm achieves the desired performance improvements.

NeuSaver: Neural Adaptive Power Consumption Optimization for Mobile Video Streaming

Video streaming services strive to support high-quality videos at higher resolutions and frame rates to improve the quality of experience (QoE). However, high-quality videos consume considerable amounts of energy on mobile devices. This paper proposes NeuSaver, which reduces the power consumption of mobile devices when streaming videos by applying an adaptive frame rate to each video chunk without compromising the user experience. NeuSaver generates a policy that can determine the appropriate frame rate for each video chunk using reinforcement learning (RL). The RL model automatically learns the policy that optimizes the QoE goals based on previous observations. NeuSaver also uses an asynchronous advantage actor-critic algorithm to reinforce the RL model quickly and robustly. Streaming servers that support NeuSaver preprocess videos into segments with various frame rates, which is similar to the process of creating videos with multiple bit rates in dynamic adaptive streaming over HTTP. NeuSaver utilizes the commonly used H.264 video codec. We evaluated NeuSaver in various experiments and a user study through four video categories along with the previously proposed model. Our experiments showed that NeuSaver effectively reduces the power consumption of mobile devices when streaming video by an average of 16.14% and up to 23.12% while maintaining high QoE.

Video Quality Model of Compression, Resolution and Frame Rate Adaptation Based on Space-Time Regularities

Being able to accurately predict the visual quality of videos subjected to various combinations of dimension reduction protocols is of high interest to the streaming video industry, given rapid increases in frame resolutions and frame rates. In this direction, we have developed a video quality predictor that is sensitive to spatial, temporal, or space-time subsampling combined with compression. Our predictor is based on new models of space-time natural video statistics (NVS). Specifically, we model the statistics of divisively normalized difference between neighboring frames that are relatively displaced. In an extensive empirical study, we found that those paths of space-time displaced frame differences that provide maximal regularity against our NVS model generally align best with motion trajectories. Motivated by this, we built a new video quality prediction engine that extracts NVS features that represent how space-time directional regularities are disturbed by space-time distortions. Based on parametric models of these regularities, we compute features that are used to train a regressor that can accurately predict perceptual quality. As a stringent test of the new model, we apply it to the difficult problem of predicting the quality of videos subjected not only to compression, but also to downsampling in space and/or time. We show that the new quality model achieves state-of-the-art (SOTA) prediction performance on the new ETRI-LIVE Space-Time Subsampled Video Quality (STSVQ) and also on the AVT-VQDB-UHD-1 database.

A narrative review of recent progress and current perspectives on video capsule endoscopy

: Since its introduction in 2000, capsule endoscopy (CE) has undergone various improvements, with several CE types currently available across the globe. This review focuses on the current status and expected future developments in small-bowel CE (SBCE) and colon CE (CCE). In addition to the demonstrated efficacy of SBCE in identifying the source of bleeding in obscure gastrointestinal bleeding (OGIB), the advent of patency capsules allowed the use of SBCE as a feasible option in patients with Crohn’s disease (CD), with several studies demonstrating the efficacy of SBCE in assessing CD activity. Following its first use in 2006, second-generation CCEs with the adaptive frame rate function, which automatically recognizes the movement speed of the capsule and accelerates the frame rate, are currently used worldwide. The utility of CCE in detecting colorectal polyps and assessing disease activity in ulcerative colitis (UC) has been reported. Recent efforts are focused on the development in artificial intelligence-based reading systems for CE images. Although there are currently few commercially available systems, several convolutional neural network-based models have been reported to detect small intestinal mucosal disorders, including erosions and ulcers, angioectasia, blood, polyps, celiac disease, and parasites. Further research is expected to reduce the burden of reading CE images on clinicians.

Subjective and Objective Quality Assessment of High Frame Rate Videos

High frame rate (HFR) videos are becoming increasingly common with the tremendous popularity of live, high-action streaming content such as sports. Although HFR contents are generally of very high quality, high bandwidth requirements make them challenging to deliver efficiently, while simultaneously maintaining their quality. To optimize trade-offs between bandwidth requirements and video quality, in terms of frame rate adaptation, it is imperative to understand the intricate relationship between frame rate and perceptual video quality. Towards advancing progression in this direction we designed a new subjective resource, called the LIVE-YouTube-HFR (LIVE-YT-HFR) dataset, which is comprised of 480 videos having 6 different frame rates, obtained from 16 diverse contents. In order to understand the combined effects of compression and frame rate adjustment, we also processed videos at 5 compression levels at each frame rate. To obtain subjective labels on the videos, we conducted a human study yielding 19,000 human quality ratings obtained from a pool of 85 human subjects. We also conducted a holistic evaluation of existing state-of-the-art Full and No-Reference video quality algorithms, and statistically benchmarked their performance on the new database. The LIVE-YT-HFR database has been made available online for public use and evaluation purposes, with hopes that it will help advance research in this exciting video technology direction. It may be obtained at \url{https://live.ece.utexas.edu/research/LIVE_YT_HFR/LIVE_YT_HFR/index.html}

Poor Quality of Small Bowel Capsule Endoscopy Images Has a Significant Negative Effect in the Diagnosis of Small Bowel Malignancy.

Background and AimsCapsule endoscopy (CE) is a visual modality; hence, diagnosis relies on image quality. We studied the contribution of image parameters to visualization quality and their effect on diagnostic certainty of small bowel (SB) lesions.MethodsFive clear CE images of common SB pathology – two vascular lesions, two inflammatory, one polyp – were processed for three image parameters to simulate poor SB conditions: opacity (color-matched to luminal content; 10–90%, 10% increments); blurriness (radius 1–10 pixels; one pixel increments); and contrast (−50-50%; 10% increments). Nine expert readers evaluated whether images were adequate for diagnosis. Points where perception of image quality changed significantly were determined for each parameter. Three further sets of SBCE images (vascular, inflammatory, and neoplastic lesions; nine images/set) were processed for four points/parameters. Twenty experienced/expert CE readers reviewed these images.ResultsThe negative effects of opacity in diagnostic certainty were mostly evident in images of neoplasia; images of vascular and inflammatory lesions were less affected. Similar results were observed with increasing blur radius, simulating movement, and poor focus. The proportions of readers finding vascular and inflammatory images adequate for diagnosis did not drop significantly at wider blur radii, while images of neoplasia were quickly deemed inadequate. Low contrast had a greater negative effect than high, most consistently in neoplastic lesions.ConclusionPoor visualization quality in all parameters affected mostly neoplastic lesions. Software to increase contrast and sharpen images can improve visualization quality; smart frame rate adaptation could improve the number of high-quality frames obtained. Thoroughness in SB cleansing is most important when there is a suspicion of neoplasia.

1111 SECOND-GENERATION MAGNETICALLY CONTROLLED CAPSULE GASTROSCOPY FOR BETTER DIAGNOSIS OF UPPER GASTROINTESTINAL TRACT: A RANDOMIZED CONTROLLED CLINICAL TRIAL

Compared to conventional endoscopy, magnetically controlled capsule gastroscopy (MCCG) can be further optimized in gastric examination time and complete visualization of upper gastrointestinal (UGI) mucosa. The second-generation MCCG (MCCG-2) was developed with higher image resolution and adaptive frame rate, and we aimed to evaluate its clinical availability for UGI examination in this study. Consecutive patients undergoing MCCG examination between May to June 2019 were prospectively enrolled and randomized to swallow the first-generation MCCG (MCCG-1) or MCCG-2 in a 1:1 ratio. The main outcomes included visualization of the esophagus and duodenum, operation related parameters, image quality, maneuverability, detection of lesions, as well as safety evaluation. Eighty patients were enrolled. In MCCG-2 group, frames captured for esophageal mucosa and Z-line were 171.00 and 2.00, significantly increased from those in MCCG-1 group with 97.00 and 0.00 (P=0.002 and 0.028). The gastric examination time was shortened from 7.78±0.97 min to 5.27±0.74 min (P<0.001), with the total running time of capsule extended from 702.83 min to 1001.99 min (P<0.001). MCCG-2 also greatly improved the image quality (P<0.001) and maneuverability (P<0.01). No statistical difference existed in the detection of lesions between the two groups, and no adverse events occurred. MCCG-2 showed better performance in mucosal visualization, examination duration and maneuverability, making better diagnosis of UGI diseases a possibility.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Second-generation magnetically controlled capsule gastroscopy with improved image resolution and frame rate: a randomized controlled clinical trial (with video)

Compared with conventional endoscopy, magnetically controlled capsule gastroscopy (MCCG) can be further optimized in gastric examination time and complete visualization of upper GI (UGI) mucosa. The second-generation MCCG (MCCG-2) was developed with higher image resolution and adaptive frame rate, and we aimed to evaluate its clinical availability for UGI examination in this study. Consecutive patients undergoing MCCG examination between May to June 2019 were prospectively enrolled and randomized to swallow the first-generation MCCG (MCCG-1) or MCCG-2 in a 1:1 ratio. The main outcomes included visualization of the esophagus and duodenum, operation-related parameters, image quality, maneuverability, detection of lesions, and safety evaluation. Eighty patients were enrolled. In the MCCG-2 group, frames captured for esophageal mucosa and Z-line were 171.00 and 2.00, significantly increased from those in the MCCG-1 group (97.00 [P= .002] and .00 [P= .028], respectively). The gastric examination time was shortened from 7.78 ± .97 minutes to 5.27 ± .74 minutes (P< .001), with the total running time of the capsule extended from 702.83 minutes to 1001.99 minutes (P< .001). MCCG-2 also greatly improved the image quality (P< .001) and maneuverability (P< .01). No statistical difference existed in the detection of lesions between the 2 groups, and no adverse events occurred. MCCG-2 showed better performance in mucosal visualization, examination duration, and maneuverability, making better diagnosis of UGI diseases a possibility. (Clinical trial registration number: NCT03977935.).

Capturing Video Frame Rate Variations via Entropic Differencing

High frame rate videos are increasingly getting popular in recent years, driven by the strong requirements of the entertainment and streaming industries to provide high quality of experiences to consumers. To achieve the best trade-offs between the bandwidth requirements and video quality in terms of frame rate adaptation, it is imperative to understand the effects of frame rate on video quality. In this direction, we devise a novel statistical entropic differencing method based on a Generalized Gaussian Distribution model expressed in the spatial and temporal band-pass domains, which measures the difference in quality between reference and distorted videos. The proposed design is highly generalizable and can be employed when the reference and distorted sequences have different frame rates. Our proposed model correlates very well with subjective scores in the recently proposed LIVE-YT-HFR database and achieves state of the art performance when compared with existing methodologies.

On the Minimum Perceptual Temporal Video Sampling Rate and Its Application to Adaptive Frame Skipping

Media technology, in particular video recording and playback, keeps improving to provide users with high-quality real and virtual visual content. In recent years, increasing the temporal sampling rate of videos and the refresh rate of displays has become one focus of technical innovation. This raises the question, how high the sampling and refresh rates should be? To answer this question, we determine the minimum temporal sampling rate at which a video should be presented to make temporal sampling imperceptible to viewers. Through a psychophysical study, we find that this minimum sampling rate depends on both the speed of the objects in the image plane and the exposure time of the recording camera. We propose a model to compute the required minimum sampling rate based on these two parameters. In addition, state-of-the-art video codecs employ motion vectors from which the local object movement speed can be inferred. Therefore, we present a procedure to compute the minimum sampling rate given an encoded video and camera exposure time. Since the object motion speed in a video may vary, the corresponding minimum frame rate is also varying. This is why the results of this paper are particularly applicable when used together with adaptive frame rate computer generated graphics or novel video communication solutions that drop insignificant frames. In our experiments, we show that videos played back at the minimum adaptive frame rate achieve an average bit rate reduction of 26% compared to constant frame rate playback, while perceptually no difference can be observed.

No significant difference in clinically relevant findings between Pillcam® SB3 and Pillcam® SB2 capsules in a United States veteran population.

BACKGROUNDCapsule endoscopy (CE) allows for a non-invasive small bowel evaluation for a wide range of gastrointestinal (GI) symptoms and diseases. Capsule technology has been rapidly advancing over recent years, often improving image frequency and quality. The Pillcam® SB3 (SB3) capsule is one such technology that offers an adaptive frame rate advantage over the previous versions of the capsule the Pillcam® SB2 (SB2). Some have proposed that this improvement in capsule technology may lead to increased diagnostic yields; however, real world clinical data is currently lacking.AIMTo evaluate the clinically relevant findings of SB3 and SB2 capsules in a population of United States veterans.METHODSA retrospective analysis of 260 consecutive CE studies was performed including 130 SB3 and 130 SB2 capsule studies. Recorded variables included: age, gender, type of capsule, body mass index, exam completion, inpatient status, opioid use, diabetes, quality of preparation, gastric transit time, small bowel transit time, indication, finding, and if the exam resulted in a change in clinical management. The primary outcome measured was the detection of clinically relevant findings between SB3 and SB2 capsules.RESULTSMean age of the study population was 67.1 ± 10.4 years and 94.2% of patients were male. Of these 28.1% were on opioid users. The most common indications for capsule procedure were occult GI bleeding (74.6%) and overt GI bleeding (14.6%). Rates of incomplete exam were similar between SB3 and SB2 groups (16.9% vs 9.2%, P = 0.066). The overall rate of clinically relevant finding was 48.9% in our study. No significant difference was observed in SB3 vs SB2 capsules for clinically relevant findings (46.2% vs 51.5%, P = 0.385) or change in clinical management (40.8% vs 50.0%, P = 0.135).CONCLUSIONOur study found no significant difference in clinically relevant findings between SB3 and SB2 capsules.

Capsule endoscopy for small-intestinal disorders: Current status.

Small-bowel capsule endoscopy (SBCE) is used widely because of its non-invasive and patient-friendly nature. SBCE can visualize entire small-intestinal mucosa and facilitate detection of small-intestinal abnormalities. In this review article, we focus on the current status of SBCE. Several platforms for SBCE are available worldwide. Third-generation SBCE (PillCam® SB3) has a high-resolution camera equipped with an adaptive frame rate system. Several software modes have been developed to reduce the reading time for capsule endoscopy and to minimize the possibility of missing lesions. The main complication of SBCE is capsule retention. Thus, the main contraindication for SBCE is known or suspected gastrointestinal obstruction unless intestinal patency is proven. Possible indications for SBCE are obscure gastrointestinal bleeding, Crohn's disease, small-intestinal polyps and tumors, and celiac disease. Colon capsule endoscopy (CCE) can observe inflamed colonic mucosa non-invasively, and allows for the continuous and non-invasive observation of the entire intestinal tract (pan-endoscopy). Recently, application of CCEas pan-enteric endoscopy for inflammatory bowel diseases (including Crohn's disease) has been reported. In the near future, reading for CE will be assisted by artificial intelligence, and reading CE videos for long periods will not be required.

Diagnostic Yields of Pillcam® SB3 versus Pillcam® SB2 Capsules in a United States Veteran Population

Introduction: Capsule endoscopy offers a non-invasive form of small bowel evaluation for a variety of gastrointestinal symptoms and diseases. Capsule technology has been rapidly advancing over recent years, often improving image frequency and quality. The Pillcam® SB3 capsule is one such technology that offers an adaptive frame rate advantage over previous capsule versions. Some have proposed that this improvement in capsule technology may lead to increased diagnostic yields; however, real world clinical data is currently lacking. Methods: Retrospective analysis of 260 consecutive (130 Pillcam® SB3 and 130 Pillcam® SB2) capsule endoscopy studies at our Veterans Affairs Medical Center was performed. Recorded variables included: Age, gender, type of capsule, body mass index (BMI), exam completion, inpatient status, quality of prep, gastric transit time (GTT), small bowel transit time (SBTT), indication, finding, and if the exam resulted in a change in clinical management. Significance (p<0.05) was assessed using t-test for normally distributed continuous variables and chi-square or Fisher's exact test as appropriate for categorical variables. Results: Group characteristics for Pillcam® SB3 and Pillcam® SB2 capsules are presented in Table 1 and included: Age (68.3 ± 11.1 vs 65.9 ± 9.5, p=0.061), male gender (93.8% vs 94.6%, p=0.790), BMI (30.1 ± 6.1 vs 30.5 ± 6.4 p=0.618), incomplete exam (16.9% vs 9.2% p=0.066), inpatient status (14.6% vs 10% p=0.257), GTT (37.7 ± 40.4 mins vs 41.4 ± 53.4 mins, p= 0.539), SBTT (223.1 ± 81.4 mins vs 208.8 ± 87.3 mins, p=0.033), and inadequate preparation (11.5% vs 13.8%, p=0.576). Procedure indications included: Occult GIB (70.8% vs 78.5%, p=0.154), overt GIB (18.5% vs 10.8% p=0.079), tumor/polyp evaluation (3.2% vs 3.8%, p=0.999), IBD (1.5% vs 3.8%, p=0.447), other (6.2% vs 3.1%, p=0.237). Capsule findings are presented in Table 2. No significant difference was observed in Pillcam® SB3 vs Pillcam® SB2 capsules for clinically relevant findings (46.2% vs 51.5%, p=0.385) or for changes in clinical management (40.8% vs 50.0%, p=0.135). Conclusion: Our study found no significant difference in clinically relevant findings between Pillcam® SB3 and Pillcam® SB2 capsules. Additionally, no significant change in clinical management was observed. Further prospective research is needed to determine if this capsule improvement enhances clinical findings or impacts clinical management.1156_A Figure 1. Baseline Demographics1156_B Figure 2. Indications and Findings of Pillcam® SB3 vs Pillcam® SB2 Capsule Studies

Similarity based image selection with frame rate adaptation and local event detection in wireless video sensor networks

Wireless Video Sensor Networks (WVSNs7unding environmental information. Those sensor nodes can locally process the information and then wirelessly transmit it to the coordinator and to the sink to be further processed. As a consequence, more abundant video and image data are collected. In such densely deployed networks, the problem of data redundancy arises when information are gathered from neighboring nodes. To overcome this problem, one important enabling technology for WVSN is data aggregation, which is essential to be cost-efficient. In this paper, we propose a new approach for data aggregation in WVSN based on images and shot similarity functions. It is deployed on two levels: the video-sensor node level and the coordinator level. At the sensor node level the proposed algorithms aim at reducing the number of frames sensed by the sensor nodes and sent to the coordinator. At the coordinator level, after receiving shots from different neighbouring sensor nodes, the similarity between these shots is computed to eliminate redundancies and to only send the frames which meet a certain condition to the sink. The similarity between shots is evaluated based on their color, edge and motion information. We evaluate our approach on a live scenario and compare the results with another approach from the literature in terms of data reduction and energy consumption. The results show that the two approaches have a significant data reduction to reduce the energy consumption, thus our approach tends to overcome the other one in terms of reducing the energy consumption related to the sensing process, and to the transmitting process while guaranteeing the detection of all the critical events at the node and the coordinator levels.

P277 A new pan enteric capsule for suspected or established IBD: A feasibility study assessing the system functionality to visualise and assess the small and large bowels

Inflammatory bowel disease (IBDs) requires evaluation of the gastrointestinal (GI) tract to assess disease extent and severity. The PillCam Crohn’s system is a new system composed of a two-headed capsule with a panoramic field of view and adaptive frame rate, customised for extensive coverage of the GI tract, to assess and follow disease severity and extent over time. The aim of this study was to assess system functionality in suspected or established IBD patients. A feasibility study was performed prospectively in 5 different centres. Study subjects ingested the new PillCam™ Crohn’s capsule after standard bowel preparation plus boosts. A patency capsule was ingested first to ensure adequate patency of the GI tract prior to capsule. The primary study endpoint was successful procedure in terms of video creation and report generation in accordance to the video reading methodology. Secondary study endpoints were subjective coverage of small bowel and colon (SBC), subjective duration of total and segmental reading time, over all video quality and occurrence/ severity of adverse events. 68 patients were screened, 54 enrolled, and 49 ingested the capsule (14 patency failure (21%), 5 withdrew consent). Forty-one patients were included in the final analysis and had no procedure-related deviations (bowel preparation materials and boosts consumption). Mean age was 40.8 years ± 15.5 (mean ± standard deviation), 46% were males. 71% of patients had established CD, 12% UC and 17% suspected CD. The disease was active in 54% of established IBD patients. Overall cleansing was regarded good or excellent in 95% of patients. All 41 videos met the primary endpoint. All capsules reached the left colon/toilet with no retention, 95% while recording. Of those with established CD, 31% had proximal disease. Gastroenterologists were satisfied with SBC coverage 6.7 ± 0.6 and 6.1 ± 1.3 (mean ± standard deviation) on a scale of 1–7 (unconfident to confident), image quality 6.1 ± 0.8 (1–7, poor to excellent), and subjective video reading time 3.7 ± 1.4 (1–7, very short to very long). The PillCam™ Crohn’s capsule allows for extensive evaluation of the entire gut of IBD patients, including those with proximal disease. The system can be used to assess disease severity, extent, and follow-up of IBD patients.

SIFT based video watermarking resistant to temporal scaling

In this paper, a blind video watermarking scheme is proposed which can resist temporal scaling such as frame dropping and frame rate adaptation due to scalable compression by exploiting the scale invariance property of the scale invariant feature transform (SIFT). A video scene can also be viewed from side plane where height is the number of rows in a video frame, width is the number of frames in the scene and depth is the number of columns in the frame. In this work, intensity values of selected embedding locations changed such that strong SIFT feature can be generated. SIFT features are extracted from side plane of the video. These newly generated SIFT features are used for watermark signal and are stored in the database for the authentication. A comprehensive set of experiments has been done to demonstrate the efficacy of the proposed scheme over the existing literature against temporal attacks.

Is capsule colonoscopy the solution for incomplete conventional colonoscopy?

The era of colon capsule endoscopy (CCE) started in 2007. Few years later second-generation CCE (CCE-2) (Medtronic, Minneapolis, USA) was launched, featuring an improved optical system allowing for nearly 360° coverage via two 172° angle cameras, and adaptive frame rate function (ranging from 4 to 35 images per second depending on capsule motion). At present the main clinical indications for CCE are: a) completion of incomplete colonoscopy; b) polyp detection; and c) investigation of inflammatory bowel disease (IBD).

A High-Fidelity and Low-Interaction-Delay Screen Sharing System

The pervasive computing environment and wide network bandwidth provide users more opportunities to share screen content among multiple devices. In this article, we introduce a remote display system to enable screen sharing among multiple devices with high fidelity and responsive interaction. In the developed system, the frame-level screen content is compressed and transmitted to the client side for screen sharing, and the instant control inputs are simultaneously transmitted to the server side for interaction. Even if the screen responds immediately to the control messages and updates at a high frame rate on the server side, it is difficult to update the screen content with low delay and high frame rate in the client side due to non-negligible time consumption on the whole screen frame compression, transmission, and display buffer updating. To address this critical problem, we propose a layered structure for screen coding and rendering to deliver diverse screen content to the client side with an adaptive frame rate. More specifically, the interaction content with small region screen update is compressed by a blockwise screen codec and rendered at a high frame rate to achieve smooth interaction, while the natural video screen content is compressed by standard video codec and rendered at a regular frame rate for a smooth video display. Experimental results with real applications demonstrate that the proposed system can successfully reduce transmission bandwidth cost and interaction delay during screen sharing. Especially for user interaction in small regions, the proposed system can achieve a higher frame rate than most previous counterparts.