74,809 research outputs found
Automatic Face Recognition System Based on Local Fourier-Bessel Features
We present an automatic face verification system inspired by known properties
of biological systems. In the proposed algorithm the whole image is converted
from the spatial to polar frequency domain by a Fourier-Bessel Transform (FBT).
Using the whole image is compared to the case where only face image regions
(local analysis) are considered. The resulting representations are embedded in
a dissimilarity space, where each image is represented by its distance to all
the other images, and a Pseudo-Fisher discriminator is built. Verification test
results on the FERET database showed that the local-based algorithm outperforms
the global-FBT version. The local-FBT algorithm performed as state-of-the-art
methods under different testing conditions, indicating that the proposed system
is highly robust for expression, age, and illumination variations. We also
evaluated the performance of the proposed system under strong occlusion
conditions and found that it is highly robust for up to 50% of face occlusion.
Finally, we automated completely the verification system by implementing face
and eye detection algorithms. Under this condition, the local approach was only
slightly superior to the global approach.Comment: 2005, Brazilian Symposium on Computer Graphics and Image Processing,
18 (SIBGRAPI
Automatic Recognition of Mammal Genera on Camera-Trap Images using Multi-Layer Robust Principal Component Analysis and Mixture Neural Networks
The segmentation and classification of animals from camera-trap images is due
to the conditions under which the images are taken, a difficult task. This work
presents a method for classifying and segmenting mammal genera from camera-trap
images. Our method uses Multi-Layer Robust Principal Component Analysis (RPCA)
for segmenting, Convolutional Neural Networks (CNNs) for extracting features,
Least Absolute Shrinkage and Selection Operator (LASSO) for selecting features,
and Artificial Neural Networks (ANNs) or Support Vector Machines (SVM) for
classifying mammal genera present in the Colombian forest. We evaluated our
method with the camera-trap images from the Alexander von Humboldt Biological
Resources Research Institute. We obtained an accuracy of 92.65% classifying 8
mammal genera and a False Positive (FP) class, using automatic-segmented
images. On the other hand, we reached 90.32% of accuracy classifying 10 mammal
genera, using ground-truth images only. Unlike almost all previous works, we
confront the animal segmentation and genera classification in the camera-trap
recognition. This method shows a new approach toward a fully-automatic
detection of animals from camera-trap images
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