1,091 research outputs found
A comparative evaluation of interest point detectors and local descriptors for visual SLAM
Abstract In this paper we compare the behavior of different interest points detectors and descriptors under the
conditions needed to be used as landmarks in vision-based simultaneous localization and mapping (SLAM).
We evaluate the repeatability of the detectors, as well as the invariance and distinctiveness of the descriptors,
under different perceptual conditions using sequences of images representing planar objects as well as 3D scenes.
We believe that this information will be useful when selecting an appropriat
Local descriptors for visual SLAM
We present a comparison of several local image descriptors in the context of visual
Simultaneous Localization and Mapping (SLAM). In visual SLAM a set of points in the
environment are extracted from images and used as landmarks. The points are represented
by local descriptors used to resolve the association between landmarks. In this paper, we
study the class separability of several descriptors under changes in viewpoint and scale.
Several experiments were carried out using sequences of images in 2D and 3D scenes
A PatchMatch-based Dense-field Algorithm for Video Copy-Move Detection and Localization
We propose a new algorithm for the reliable detection and localization of
video copy-move forgeries. Discovering well crafted video copy-moves may be
very difficult, especially when some uniform background is copied to occlude
foreground objects. To reliably detect both additive and occlusive copy-moves
we use a dense-field approach, with invariant features that guarantee
robustness to several post-processing operations. To limit complexity, a
suitable video-oriented version of PatchMatch is used, with a multiresolution
search strategy, and a focus on volumes of interest. Performance assessment
relies on a new dataset, designed ad hoc, with realistic copy-moves and a wide
variety of challenging situations. Experimental results show the proposed
method to detect and localize video copy-moves with good accuracy even in
adverse conditions
An Evaluation of Popular Copy-Move Forgery Detection Approaches
A copy-move forgery is created by copying and pasting content within the same
image, and potentially post-processing it. In recent years, the detection of
copy-move forgeries has become one of the most actively researched topics in
blind image forensics. A considerable number of different algorithms have been
proposed focusing on different types of postprocessed copies. In this paper, we
aim to answer which copy-move forgery detection algorithms and processing steps
(e.g., matching, filtering, outlier detection, affine transformation
estimation) perform best in various postprocessing scenarios. The focus of our
analysis is to evaluate the performance of previously proposed feature sets. We
achieve this by casting existing algorithms in a common pipeline. In this
paper, we examined the 15 most prominent feature sets. We analyzed the
detection performance on a per-image basis and on a per-pixel basis. We created
a challenging real-world copy-move dataset, and a software framework for
systematic image manipulation. Experiments show, that the keypoint-based
features SIFT and SURF, as well as the block-based DCT, DWT, KPCA, PCA and
Zernike features perform very well. These feature sets exhibit the best
robustness against various noise sources and downsampling, while reliably
identifying the copied regions.Comment: Main paper: 14 pages, supplemental material: 12 pages, main paper
appeared in IEEE Transaction on Information Forensics and Securit
Local Descriptor by Zernike Moments for Real-time Keypoint Matching
This paper presents a real-time keypoint matching
algorithm using a local descriptor derived by Zernike
moments. From an input image, we find a set of keypoints
by using an existing corner detection algorithm.
At each keypoint we extract a fixed size image patch
and compute a local descriptor derived by Zernike
moments. The proposed local descriptor is invariant to
rotation and illumination changes. In order to speed
up the computation of Zernike moments, we compute
the Zernike basis functions in advance and store them
in a set of lookup tables. The matching is performed
with an Approximate Nearest Neighbor (ANN) method
and refined by a RANSAC algorithm. In the
experiments we confirmed that videos of frame size
320×240 with the scale, rotation, illumination and
even 3D viewpoint changes are processed at 25~30Hz
using the proposed method. Unlike existing keypoint
matching algorithms, our approach also works in realtime
for registering a reference image
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