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Given a query image, retrieving images depicting the same object in a large scale database is becoming an urgent and challenging task. Recently, Compact Description for Visual Search (CDVS) is drafted by the ISO/IEC Moving Pictures Experts Group (MPEG) to support image retrieval applications, and it has been published as an international standard. Unfortunately, with regard to applications with hugely...
Photometric stereo enables the estimation of surface normals from images that were captured using different known lighting directions. The classical photometric stereo method requires at least three images to determine the normals of a given scene. This method therefore cannot be applied to a dynamic scene, because it is assumed that the scene should remain static while the required images are captured...
Despite being an essential prerequisite at the basis of many applications ranging from surveillance to computational photography, the problem of initial background estimation seems to be marginally investigated. In this paper, we present a reliable CNN-based solution to estimate the initial background (BG) of a scene, given not necessarily a whole sequence but just a small set of frames containing...
Background modeling and subtraction are essential to video surveillance applications. There are two main issues related to background modeling: how to initialize the background model, and how to update the model based on observations. In this paper, we consider the first issue with the aim of generating a clear background image that does not contain foreground objects or noise. We used a bidirectional...
In this paper, with the help of controllable active near-infrared (NIR) lights, we construct near-infrared differential (NIRD) images. Based on reflection model, NIRD image is believed to contain the lighting difference between images with and without active NIR lights. Two main characteristics based on NIRD images are exploited to conduct spoofing detection. Firstly, there exist obviously spoofing...
Underwater images suffer from severe perceptual/visual degradation, due to the dense and non-uniform medium, causing scattering and attenuation of the propagated light that is sensed. Typical restoration methods rely on the popular Dark Channel Prior to estimate the light attenuation factor, and subtract the back-scattered light influence to invert the underwater imaging model. However, as a consequence...
This paper introduces an effective active contour model for texture segmentation. To improve the robustness against noise and illumination, a novel descriptor named local statistical variation degree (LSVD) is presented to express textural features, which uses corner point deletion and isolated region detection operations to eliminate image patches unrelated with object regions. And then the fused...
This paper presents a study on a family of local hexagonal and multi-scale operators useful for texture analysis. The hexagonal grid shows an attractive rotation symmetry with uniform neighbour distances. The operator depicts a closed connected curve (1D periodic). It is resized within a scale interval during the conversion from the original square grid to the virtual hexagonal grid. Complementary...
A great deal of features detectors and descriptors are proposed every years for several computer vision applications. In this paper, we concentrate on dense detector applied to different descriptors. Eight descriptors are compared, three from gradient based family (SIFT, SURF, DAISY), others from binary category (BRIEF, ORB, BRISK, FREAK and LATCH). These descriptors are created and defined with certain...
Melanoma is the most aggressive form of skin cancer and is on rise. There exists a research trend for computerized analysis of suspicious skin lesions for malignancy using images captured by digital cameras. Analysis of these images is usually challenging due to existence of disturbing factors such as illumination variations and light reflections from skin surface. One important stage in diagnosis...
In low or moderate ambient light conditions, flash image is sharp and less noisy as compared to no-flash image; however, it contains unwanted sharp shadows at silhouettes. In our previous work, we proposed a new flash image shadow detection method which utilizes a pair of flash/no-flash images to detect sharp shadows at silhouettes; however, the method often leads to false shadow detection due its...
In this paper, we present a reflectance-aware optical flow technique for nonrigidly aligning images captured in different lighting environments. We consider alignment between two specific lighting conditions of particular relevance to object capture using a light stage. The technique uses optical flow combined with three image transformation functions, namely a) the Illumination-Independent image...
This paper presents a photometric stereo method with nonisotropic point light sources. Subject to the non-uniform lighting conditions produced by the nonisotropic point sources, each incident light ray should be precisely determined so as to realize an accurate calculation of surface normal. In the proposed method, radiance model of the light source is firstly introduced to the classical photometric...
In this paper, we propose a robust method for face reconstruction using a single color image. A 3D morphable model is used to reconstruct a smooth 3D face shape. To find the correspondence between model vertices and image pixels, landmarks are updated using SIFT flow which is illumination and rotation invariant. To reconstruct more detailed information, depth values are refined using a shape from...
The ideal biometric template protection scheme possesses the properties of irreversibility, revocability, unlinkability, and good performance. These properties protect the security of the biometrics system as well as users' privacy. Practical systems, however, fall short of this ideal. In this paper, we present a novel protection scheme that achieves this ideal under the circumstance that a subject's...
Face detection is a vital step in the process of extracting semantic information about the driver's state, such as distraction and fatigue, from pixel values in images looking at the driver. Therefore, in the context of time and safety critical situation like driving, efficient use of time and reliable detection of faces is essential. While challenges like lighting and occlusion are prevalent in the...
The color constancy problem is addressed by structured-output regression on the values of the fully-connected layers of a convolutional neural network. The AlexNet and the VGG are considered and VGG slightly outperformed AlexNet. Best results were obtained with the first fully-connected “fc6” layer and with multi-output support vector regression. Experiments on the SFU Color Checker and Indoor Dataset...
Cascade regression framework has been successfully applied to facial landmark detection and achieves state-of-the-art performance recently. It requires large number of facial images with labeled landmarks for training regression models. We propose to use cascade regression framework to detect eye center by capturing its contextual and shape information of other related eye landmarks. While for eye...
In this paper, we present a new approach for periocular recognition based on the Symmetry Assessment by Feature Expansion (SAFE) descriptor, which encodes the presence of various symmetric curve families around image key points. We use the sclera center as single key point for feature extraction, highlighting the object-like identity properties that concentrates to this unique point of the eye. As...
In this work, we propose a metric adaptation method for set-based face verification and evaluate it on the newly released IARPA Janus Benchmark A (IJB-A) dataset and its extended version, the Janus Challenging Set 2 (CS2). A template-specific metric is trained to adaptively learn the discriminative information in test templates and the negative training set, which contains subjects that are mutually...
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