3,236 research outputs found
LR-CNN: Local-aware Region CNN for Vehicle Detection in Aerial Imagery
State-of-the-art object detection approaches such as Fast/Faster R-CNN, SSD,
or YOLO have difficulties detecting dense, small targets with arbitrary
orientation in large aerial images. The main reason is that using interpolation
to align RoI features can result in a lack of accuracy or even loss of location
information. We present the Local-aware Region Convolutional Neural Network
(LR-CNN), a novel two-stage approach for vehicle detection in aerial imagery.
We enhance translation invariance to detect dense vehicles and address the
boundary quantization issue amongst dense vehicles by aggregating the
high-precision RoIs' features. Moreover, we resample high-level semantic pooled
features, making them regain location information from the features of a
shallower convolutional block. This strengthens the local feature invariance
for the resampled features and enables detecting vehicles in an arbitrary
orientation. The local feature invariance enhances the learning ability of the
focal loss function, and the focal loss further helps to focus on the hard
examples. Taken together, our method better addresses the challenges of aerial
imagery. We evaluate our approach on several challenging datasets (VEDAI,
DOTA), demonstrating a significant improvement over state-of-the-art methods.
We demonstrate the good generalization ability of our approach on the DLR 3K
dataset.Comment: 8 page
Fast and Accurate, Convolutional Neural Network Based Approach for Object Detection from UAV
Unmanned Aerial Vehicles (UAVs), have intrigued different people from all
walks of life, because of their pervasive computing capabilities. UAV equipped
with vision techniques, could be leveraged to establish navigation autonomous
control for UAV itself. Also, object detection from UAV could be used to
broaden the utilization of drone to provide ubiquitous surveillance and
monitoring services towards military operation, urban administration and
agriculture management. As the data-driven technologies evolved, machine
learning algorithm, especially the deep learning approach has been intensively
utilized to solve different traditional computer vision research problems.
Modern Convolutional Neural Networks based object detectors could be divided
into two major categories: one-stage object detector and two-stage object
detector. In this study, we utilize some representative CNN based object
detectors to execute the computer vision task over Stanford Drone Dataset
(SDD). State-of-the-art performance has been achieved in utilizing focal loss
dense detector RetinaNet based approach for object detection from UAV in a fast
and accurate manner.Comment: arXiv admin note: substantial text overlap with arXiv:1803.0111
Leveraging Traffic and Surveillance Video Cameras for Urban Traffic
The objective of this project was to investigate the use of existing video resources, such as traffic cameras, police cameras, red light cameras, and security cameras for the long-term, real-time collection of traffic statistics. An additional objective was to gather similar statistics for pedestrians and bicyclists. Throughout the course of the project, we investigated several methods for tracking vehicles under challenging conditions. The initial plan called for tracking based on optical flow. However, it was found that current optical flow–estimating algorithms are not well suited to low-quality video—hence, developing optical flow methods for low-quality video has been one aspect of this project. The method eventually used combines basic optical flow tracking with a learning detector for each tracked object—that is, the object is tracked both by its apparent movement and by its appearance should it temporarily disappear from or be obscured in the frame. We have produced a prototype software that allows the user to specify the vehicle trajectories of interest by drawing their shapes superimposed on a video frame. The software then tracks each vehicle as it travels through the frame, matches the vehicle’s movements to the most closely matching trajectory, and increases the vehicle count for that trajectory. In terms of pedestrian and bicycle counting, the system is capable of tracking these “objects” as well, though at present it is not capable of distinguishing between the three classes automatically. Continuing research by the principal investigator under a different grant will establish this capability as well.Illinois Department of Transportation, R27-131Ope
Road User Detection in Videos
Successive frames of a video are highly redundant, and the most popular
object detection methods do not take advantage of this fact. Using multiple
consecutive frames can improve detection of small objects or difficult examples
and can improve speed and detection consistency in a video sequence, for
instance by interpolating features between frames. In this work, a novel
approach is introduced to perform online video object detection using two
consecutive frames of video sequences involving road users. Two new models,
RetinaNet-Double and RetinaNet-Flow, are proposed, based respectively on the
concatenation of a target frame with a preceding frame, and the concatenation
of the optical flow with the target frame. The models are trained and evaluated
on three public datasets. Experiments show that using a preceding frame
improves performance over single frame detectors, but using explicit optical
flow usually does not
Road User Detection in Videos
Successive frames of a video are highly redundant, and the most popular
object detection methods do not take advantage of this fact. Using multiple
consecutive frames can improve detection of small objects or difficult examples
and can improve speed and detection consistency in a video sequence, for
instance by interpolating features between frames. In this work, a novel
approach is introduced to perform online video object detection using two
consecutive frames of video sequences involving road users. Two new models,
RetinaNet-Double and RetinaNet-Flow, are proposed, based respectively on the
concatenation of a target frame with a preceding frame, and the concatenation
of the optical flow with the target frame. The models are trained and evaluated
on three public datasets. Experiments show that using a preceding frame
improves performance over single frame detectors, but using explicit optical
flow usually does not
Small-Object Detection in Remote Sensing Images with End-to-End Edge-Enhanced GAN and Object Detector Network
The detection performance of small objects in remote sensing images is not
satisfactory compared to large objects, especially in low-resolution and noisy
images. A generative adversarial network (GAN)-based model called enhanced
super-resolution GAN (ESRGAN) shows remarkable image enhancement performance,
but reconstructed images miss high-frequency edge information. Therefore,
object detection performance degrades for small objects on recovered noisy and
low-resolution remote sensing images. Inspired by the success of edge enhanced
GAN (EEGAN) and ESRGAN, we apply a new edge-enhanced super-resolution GAN
(EESRGAN) to improve the image quality of remote sensing images and use
different detector networks in an end-to-end manner where detector loss is
backpropagated into the EESRGAN to improve the detection performance. We
propose an architecture with three components: ESRGAN, Edge Enhancement Network
(EEN), and Detection network. We use residual-in-residual dense blocks (RRDB)
for both the ESRGAN and EEN, and for the detector network, we use the faster
region-based convolutional network (FRCNN) (two-stage detector) and single-shot
multi-box detector (SSD) (one stage detector). Extensive experiments on a
public (car overhead with context) and a self-assembled (oil and gas storage
tank) satellite dataset show superior performance of our method compared to the
standalone state-of-the-art object detectors.Comment: This paper contains 27 pages and accepted for publication in MDPI
remote sensing journal. GitHub Repository:
https://github.com/Jakaria08/EESRGAN (Implementation
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