Histogram of Oriented Gradients (HOG) based methods for the detection of humans have become one of the most reliable methods of detecting pedestrians with a single passive imaging camera. However, they are not 100 percent reliable. This paper presents an improved tracker for the monitoring of pedestrians within images. The Parallel HOG and Correlation Tracking (PHACT) algorithm utilises self learning to overcome the drifting problem. A detection algorithm that utilises HOG features runs in parallel to an adaptive and stateful correlator. The combination of both acting in a cascade provides a much more robust tracker than the two components separately could produce.
Video surveillance has become common for the maintenance of security in a wide variety of applications. However, the increasingly large amounts of data produced from multiple video camera feeds is making it increasingly difficult for human operators to monitor the imagery for activities likely to give rise to threats. This has led to the development of different automated surveillance systems that can detect, track and analyze video sequences both online and offline and report potential security risks. Segmentation of objects is an important part of such systems and numerous background segmentation techniques have been used in the literature. One common challenge faced by these techniques is adaption in different lighting environments. A new improved background segmentation technique has been presented in this where the main focus is to accurately segment potentially important objects by reducing the overall false detection rate. Historic edge maps and tracking results are analyzed for this purpose. The idea is to obtain an up to date edge map of the segmented region highlighted as foreground areas and compare them with the stored results. The edge maps are obtained using a novel adaptive edge orientation based technique where orientation of the edge is used. Experimental results have shown that the discussed technique gives over 85% matching results even in severe lighting changes.
Accurately generating an alarm for a moving door is a precondition for tracking, recognizing and segmenting objects or
people entering or exiting the door. The challenge of generating an alarm when a door event occurs is difficult when
dealing with complex doors, moving cameras, objects moving or an obscured entrance of the door, together with the
presence of varying illumination conditions such as a door-way light being switched on. In this paper, we propose an
effective method of tracking the door motion using edge-map information contained within a localised region at the top
of the door. The region is located where the top edge of the door displaces every time the door is opened or closed. The
proposed algorithm uses the edge-map information to detect the moving corner in the small windowed area with the help
of a Harris corner detector. The moving corner detected in the selected region gives an exact coordinate of the door
corner in motion, thus helping in generating an alarm to signify that the door is being opened or closed. Additionally, due
to the prior selection of the small region, the proposed method nullifies the adverse effects mentioned above and helps
prevent different objects that move in front of the door affecting its efficient tracking. The proposed overall method also
generates an alarm to signify whether the door was displaced to provide entry or exit. To do this, an active contour
orientation is computed to estimate the direction of motion of objects in the door area when an event occurs. This
information is used to distinguish between objects and entities entering or exiting the door. A Hough transform is applied
on a specific region in the frame to detect a line, which is used to perform error correction to the selected windows. The
detected line coordinates are used to nullify the effects of a moving camera platform, thus improving the robustness of
the results. The developed algorithm has been tested on all the Door Zone video sequences contained with the United
Kingdom Home Office i-LIDs dataset, with promising results.
Detection and tracking of illegally parked vehicles are usually considered as crucial steps in the development
of a video-surveillance based traffic-management system. The major challenge in this task lies in making the
tracking phase illumination-change tolerant. The paper presents a two-stage process to detect vehicles parked
illegally and monitor these in subsequent frames. Chromaticity and brightness distortion estimates are used in
the first stage to segment the foreground objects from the remainder of the scene. The process then locks onto all
stationary 'vehicle'-size patches, parts of which overlap with the regions of interest marked interactively a priori.
The second stage of the process is applied subsequently to track all the illegally parked vehicles detected during
the first stage. All the locked patches are filtered using a difference-of-Gaussian (DoG) filter operated at three
different scales to capture a broad range of information. In succeeding frames patches at the same locations are
similarly DoG filtered at the three different scales and the results matched with the corresponding ones initially
generated. A combined score based on correlation estimates is used to track and confirm the existence of the
illegally parked vehicles. Use of the DoG filter helps in extracting edge based features of the patches thus making
the tracking process broadly illumination-invariant. The two-stage approach has been tested on the United
Kingdom Home Office iLIDS dataset with encouraging results.
A robust human intrusion detection technique using hue-saturation histograms is presented in this paper. Initially a
region of interest (ROI) is manually identified in the scene viewed by a single fixed CCTV camera. All objects in the
ROI are automatically demarcated from the background using brightness and chromaticity distortion parameters. The
segmented objects are then tracked using correlation between hue-saturation based bivariate distributions. The technique
has been applied on all the 'Sterile Zone' sequences of the United Kingdom Home Office iLIDS dataset and its
performance is evaluated with over 70% positive results.
Surveillance and its security applications have been critical subjects recently with various studies placing a high demand
on robust computer vision solutions that can work effectively and efficiently in complex environments without human
intervention. In this paper, an efficient illumination invariant template generation and tracking method to identify and
track abandoned objects (bags) in public areas is described. Intensity and chromaticity distortion parameters are initially
used to generate a binary mask containing all the moving objects in the scene. The binary blobs in the mask are tracked,
and those found static through the use of a 'centroid-range' method are segregated. A Laplacian of Gaussian (LoG) filter
is then applied to the parts of the current frame and the average background frame, encompassed by the static blobs, to
pick up the high frequency components. The total energy is calculated for both the frames, current and background,
covered by the detected edge map to ensure that illumination change has not resulted in false segmentation. Finally, the
resultant edge-map is registered and tracked through the use of a correlation based matching process. The algorithm has
been successfully tested on the iLIDs dataset, results being presented in this paper.
KEYWORDS: RGB color model, Binary data, Sensors, Detection and tracking algorithms, Distortion, Algorithm development, Cameras, Roentgenium, Information security, Intelligence systems
Baggage abandoned in public places can pose a serious security threat. In this paper a two-stage approach
that works on video sequences captured by a single immovable CCTV camera is presented. At first, foreground
objects are segregated from static background objects using brightness and chromaticity distortion parameters
estimated in the RGB colour space. The algorithm then locks on to binary blobs that are static and of 'bag' sizes;
the size constraints used in the scheme are chosen based on empirical data. Parts of the background frame and
current frames covered by a locked mask are then tracked using a 1-D (unwrapped) pattern generated using a
bi-variate frequency distribution in the rg chromaticity space. Another approach that uses edge maps instead of
patterns generated using the fragile colour information is discussed. In this approach the pixels that are part of
an edge are marked using a novel scheme that utilizes four 1-D Laplacian kernels; tracking is done by calculating
the total entropy in the intensity images in the sections encompassed by the binary edge maps. This makes the
process broadly illumination invariant. Both the algorithms have been tested on the iLIDS dataset (produced
by the Home Office Scientific Development Branch in partnership with Security Service, United Kingdom) and
the results obtained are encouraging.
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