351 research outputs found
GPU Acceleration of Image Convolution using Spatially-varying Kernel
Image subtraction in astronomy is a tool for transient object discovery such
as asteroids, extra-solar planets and supernovae. To match point spread
functions (PSFs) between images of the same field taken at different times a
convolution technique is used. Particularly suitable for large-scale images is
a computationally intensive spatially-varying kernel. The underlying algorithm
is inherently massively parallel due to unique kernel generation at every pixel
location. The spatially-varying kernel cannot be efficiently computed through
the Convolution Theorem, and thus does not lend itself to acceleration by Fast
Fourier Transform (FFT). This work presents results of accelerated
implementation of the spatially-varying kernel image convolution in multi-cores
with OpenMP and graphic processing units (GPUs). Typical speedups over ANSI-C
were a factor of 50 and a factor of 1000 over the initial IDL implementation,
demonstrating that the techniques are a practical and high impact path to
terabyte-per-night image pipelines and petascale processing.Comment: 4 pages. Accepted to IEEE-ICIP 201
Occlusion Handling using Semantic Segmentation and Visibility-Based Rendering for Mixed Reality
Real-time occlusion handling is a major problem in outdoor mixed reality
system because it requires great computational cost mainly due to the
complexity of the scene. Using only segmentation, it is difficult to accurately
render a virtual object occluded by complex objects such as trees, bushes etc.
In this paper, we propose a novel occlusion handling method for real-time,
outdoor, and omni-directional mixed reality system using only the information
from a monocular image sequence. We first present a semantic segmentation
scheme for predicting the amount of visibility for different type of objects in
the scene. We also simultaneously calculate a foreground probability map using
depth estimation derived from optical flow. Finally, we combine the
segmentation result and the probability map to render the computer generated
object and the real scene using a visibility-based rendering method. Our
results show great improvement in handling occlusions compared to existing
blending based methods
Panoramic Background Modeling for PTZ Cameras with Competitive Learning Neural Networks
The construction of a model of the background of a
scene still remains as a challenging task in video surveillance systems, in particular for moving cameras. This work presents a novel approach for constructing a panoramic background model based on competitive learning neural networks and a subsequent piecewise linear interpolation by Delaunay triangulation. The approach can handle arbitrary camera directions and zooms for a Pan-Tilt-Zoom (PTZ) camera-based surveillance system. After testing the proposed approach on several indoor sequences, the results demonstrate that the proposed method is effective and suitable to use for real-time video surveillance applications.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Parallel proccessing applied to object detection with a Jetson TX2 embedded system.
Video streams from panoramic cameras represent a powerful tool for automated surveillance systems, but naïve implementations typically require very intensive computational loads for applying deep learning models for automated detection and tracking of objects of interest, since these models require relatively high resolution to reliably perform object detection. In this paper, we report a host of improvements to our previous state-of-the-art software system to reliably detect and track objects in video streams from panoramic cameras, resulting in an increase in the processing framerate in a Jetson TX2 board, with respect to our previous results. Depending on the number of processes and the load profile, we observe up to a five-fold increase in the framerate.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Strategy for Foreground Movement Identification Adaptive to Background Variations
Video processing has gained a lot of significance because of its applications in various areas of research. This includes monitoring movements in public places for surveillance. Video sequences from various standard datasets such as I2R, CAVIAR and UCSD are often referred for video processing applications and research. Identification of actors as well as the movements in video sequences should be accomplished with the static and dynamic background. The significance of research in video processing lies in identifying the foreground movement of actors and objects in video sequences. Foreground identification can be done with a static or dynamic background. This type of identification becomes complex while detecting the movements in video sequences with a dynamic background. For identification of foreground movement in video sequences with dynamic background, two algorithms are proposed in this article. The algorithms are termed as Frame Difference between Neighboring Frames using Hue, Saturation and Value (FDNF-HSV) and Frame Difference between Neighboring Frames using Greyscale (FDNF-G). With regard to F-measure, recall and precision, the proposed algorithms are evaluated with state-of-art techniques. Results of evaluation show that, the proposed algorithms have shown enhanced performance
An Approach to Distance Estimation with Stereo Vision Using Address-Event-Representation
Image processing in digital computer systems usually considers the
visual information as a sequence of frames. These frames are from cameras that
capture reality for a short period of time. They are renewed and transmitted at a
rate of 25-30 fps (typical real-time scenario). Digital video processing has to
process each frame in order to obtain a result or detect a feature. In stereo
vision, existing algorithms used for distance estimation use frames from two
digital cameras and process them pixel by pixel to obtain similarities and
differences from both frames; after that, depending on the scene and the
features extracted, an estimate of the distance of the different objects of the
scene is calculated. Spike-based processing is a relatively new approach that
implements the processing by manipulating spikes one by one at the time they
are transmitted, like a human brain. The mammal nervous system is able to
solve much more complex problems, such as visual recognition by
manipulating neuron spikes. The spike-based philosophy for visual information
processing based on the neuro-inspired Address-Event-Representation (AER) is
achieving nowadays very high performances. In this work we propose a two-
DVS-retina system, composed of other elements in a chain, which allow us to
obtain a distance estimation of the moving objects in a close environment. We
will analyze each element of this chain and propose a Multi Hold&Fire
algorithm that obtains the differences between both retinas.Ministerio de Ciencia e Innovación TEC2009-10639-C04-0
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