Real-time moving object detection for video monitoring systems

Moving object detection is one of the challenging problems in video monitoring systems, especially when the illumination changes and shadow exists. Amethod for real-time moving object detection is described. Anew background model is proposed to handle the illumination varition problem. With optical flow technology and background subtraction, a moving object is extracted quickly and accurately. An effective shadow elimination algorithm based on color features is used to refine the moving obj ects. Experimental results demonstrate that the proposed method can update the background exactly and quickly along with the varition of illumination, and the shadow can be eliminated effectively. The proposed algorithm is a real-time one which the foundation for further object recognition and understanding of video mum＇toting systems.

Intensity Retrieved from Public Monitoring Video——Cases from the May 12,2008,Wenchuan Earthquake

Macroseismic investigation is presented with a new potential means of investigation in the "digital age". In this paper we studied several cases in the May 12, 2008, Wenchuan M_S8.0 earthquake with a view to exploring the feasibility of retrieving intensity, or even strong ground motion parameters, from public monitoring video which was originally deployed for security purposes. We used public monitoring video records from 44 sites across the meizoseismal region and its surroundings to estimate the intensity. By using the video from a bank in Dujiangyan, Sichuan Province and making the simple assumption that ground vibration is in the form of a propagating harmonic wave, we estimated that the local ground motion acceleration was 0.14g.

Scalable Compression Algorithm for Video Monitoring System

A layered compression algorithm is presented which delivers spatial scalable encoded bit streams for remote video monitoring system. The complexity of the algorithm is modest and is well suited to real time implementation. Based on the layered compression algorithm, a codec system model is established. High-speed video compression can be realized with parallel data compression in this codec system. For image reconstruction, a prediction method using two nearest pix points is presented.

Using video imagery to reconstruct the 3D intertidal terrain along a beach with multiple cusps

A high-frequency,high-resolution shore-based video monitoring system(VMS)was installed on a macrotidal(tidal amplitude>4 m)beach with multiple cusps along the Quanzhou coast,China.Herein,we propose a video imagery-based method that is coupled with waterline and water level observations to reconstruct the terrain of the intertidal zone over one tidal cycle.Furthermore,the beach cusp system(BCS)was precisely processed and embedded into the digital elevation model(DEM)to more effectively express the microrelief and detailed characteristics of the intertidal zone.During a field experiment conducted in January 2022,the reconstructed DEM was deemed satisfactory.The DEM was verified by RTK-GPS and had an average vertical root mean square error along corresponding RTK-GPS-derived intertidal profiles and corresponding BCS points of 0.134 m and 0.065 m,respectively.The results suggest that VMSs are an effective tool for investigating coastal geomorphic processes.

Assessing nest attentiveness of Common Terns via video cameras and temperature loggers

Background:While nest attentiveness plays a critical role in the reproductive success of avian species,nest attentiveness data with high temporal resolution is not available for many species.However,improvements in both video monitoring and temperature logging devices present an opportunity to increase our understanding of this aspect of avian behavior.Methods:To investigate nest attentiveness behaviors and evaluate these technologies,we monitored 13 nests across two Common Tern(Sterna hirundo)breeding colonies with a paired video camera-temperature logger approach,while monitoring 63 additional nests with temperature loggers alone.Observations occurred from May to August of 2017 on Poplar(Chesapeake Bay,Maryland,USA)and Skimmer Islands(Isle of Wight Bay,Maryland,USA).We examined data respective to four times of day:Morning(civil dawn‒11:59),Peak(12:00‒16:00),Cooling(16:01‒civil dusk),and Night(civil dusk‒civil dawn).Results:While successful nests had mostly short duration off-bouts and maintained consistent nest attentiveness throughout the day,failed nests had dramatic reductions in nest attentiveness during the Cooling and Night periods(p<0.05)with one colony experiencing repeated nocturnal abandonment due to predation pressure from a Great Horned Owl(Bubo virginianus).Incubation appeared to ameliorate ambient temperatures during Night,as nests were significantly warmer during Night when birds were on versus off the nest(p<0.05).Meanwhile,off-bouts during the Peak period occurred during higher ambient temperatures,perhaps due to adults leaving the nest during the hottest periods to perform belly soaking.Unfortunately,temperature logger data alone had limited ability to predict nest attentiveness status during shorter bouts,with results highly dependent on time of day and bout duration.While our methods did not affect hatching success(p>0.05),video-monitored nests did have significantly lower clutch sizes(p<0.05).Conclusions:The paired use of iButtons and video cameras enabled a detailed description of the incubation behavior of COTE.However,while promising for future research,the logistical and potential biological complications involved in the use of these methods suggest that careful planning is needed before these devices are utilized to ensure data is collected in a safe and successful manner.

Field observation of wave overtopping at sea dike using shore-based video images

Wave overtopping at a sea dike was observed using video images during a storm in July 2018 at Rizhao Coast,China.A shore-based video monitoring system was mounted to collect coastal images with a sample frequency of 1 Hz in the beginning 10 min of each hour during daylight.A method to extract the frequency,location,width and duration of individual overtopping events based on the shore-based video monitoring system was developed.A total of 6252 individual overtopping events were detected over a 360m long sea dike during the storm of 10 h in a safe and labor-saving way,enabling a detailed analysis of the temporal and spatial variation of wave overtopping.The temporal variation of overtopping duration,frequency and volume is basically in sync with the change of tidal level(R=0.87,0.82 and 0.76,respectively).The increase of wave height increases the overtopping frequency significantly.We found a high correlation between the hourly observed data and the predicted results of two commonly used formulae.Unlike the previous field measurements of overtopping that were limited in a single location,significant spatial variation of overtopping in the alongshore direction is found.The overtopping volume varies with a factor of 6 within the range of several wave lengths.It is further revealed that the spatial variation of overtopping is highly correlated with the alongshore variation of surf zone width with a correlation coefficient of 0.895.The present study suggests the feasibility of shore-based video monitoring technique to capture the main features of wave overtopping at coastal dikes,providing new possibilities to monitor wave overtopping in the field and to improve prediction tools.

Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma

Background::Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope.The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma(VS),as an alternative to a binocular surgical microscope.Methods::Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018.The demographics and tumor characteristics(size,Koos grade,composition[cystic or solid mass])were matched between the two groups of patients.The following outcome measurements were compared between the two groups:duration of surgery,volume of blood loss,extent of tumor resection,number of operating field adjustments,pre-and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery,complications and surgeons’comfortability.Results::A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope(cases,n=39)or a surgical microscope(control,n=42).Patients in the two groups had comparable tumor location(P=0.439),Koos grading(P=0.867),and composition(P=0.891).While no significant differences in the duration of surgery(P=0.172),extent of tumor resection(P=0.858),facial function(P=0.838),and hearing ability(P=1.000),patients operated on under an exoscope had less blood loss(P=0.036)and a fewer field adjustments(P<0.001).Both primary and assistant surgeons reported a high level of comfort operating under the exoscope(P=0.001 and P<0.001,respectively).Conclusions::The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs,as compared to a surgical microscope.After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax,the exoscope system provided a comfortable,high-resolution visualization without compromising operational efficiency and patient safety.