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Multi-target tracking plays a key role in many computer vision applications including robotics, human-computer interaction, event recognition, etc., and has received increasing attention in past several years. Starting with an object detector is one of many approaches used by existing multi-target tracking methods to create initial short tracks called tracklets. These tracklets are then gradually...
In this paper, we describe a calibration method for multi-camera-projector systems in which sensors face each other as well as share a common viewpoint. We use a translucent planar sheet framed in PVC piping as a calibration target which is placed at multiple positions and orientations within a scene. In each position, the target is captured by the cameras while it is being illuminated by a set of...
We propose a segmentation algorithm for the purposes of large-scale flower species recognition. Our approach is based on identifying potential object regions at the time of detection. We then apply a Laplacian-based segmentation, which is guided by these initially detected regions. More specifically, we show that 1) recognizing parts of the potential object helps the segmentation and makes it more...
We address the problem of automatic face detection and tracking in uncontrolled scenarios using a pan-tilt-zoom (PTZ) network camera, which could prove most helpful in forensic applications. The detected faces are associated with the corresponding people and trajectories. The dynamic nature of real-world scenarios and real-time restrictions complicate our task. Different from previous work which use...
Event recognition has been an important topic in computer vision research due to its many applications. However, most of the work has focused on videos taken from a fixed camera, known environments and basic events. Here, we focus on classification of unconstrained, web videos into much higher level activities. We follow the approach of constructing fixed length feature vectors from local feature...
Large scale, class imbalanced data classification is a challenging task that occurs frequently in several computer vision tasks such as web video retrieval. A number of algorithms have been proposed in literature that approach this problem from different perspectives (e.g. Sampling, Cost-sensitive learning, Active learning). The challenge is two fold in this task — first the data imbalance causes...
As iris recognition systems have been deployed in many security areas, liveness detection that can distinguish between real iris patterns and fake ones becomes an important module. Most existing algorithms focus on the appearance difference between real and fake iris (for example, printed patterns, cosmetic contact lenses etc.) which is a very difficult problem. Instead of studying image properties...
In a lipreading system, lip extraction is a fundamental method that directly affects the final speech recognition results. However, most existing systems need to detect some facial features as prior-knowledge to construct the initial contour, and any erroneous feature detection will lead to an incorrect lip extraction. In order to solve this problem, this paper presents a new framework which integrates...
Many applications use multiple cameras to simultaneously capture imagery of a scene from a rigid, moving camera system over time. Multiple cameras often provide unique viewing angles but also additional levels of detail of a scene at different spatio-temporal resolutions. However, in order to benefit from this added information the sources must often be temporally aligned. As a result of cost and...
A quality impairment assessment along with a quality score would enable Automatic Fingerprint Identification Systems (AFIS) to make appropriate decisions to a) reject the fingerprint and recapture another sample, b) use other fingers or biometric features for recognition, c) use image enhancement techniques. Our approach provides a quality score in addition to a quality impairment assessment into...
We present a new Video Fire Detection (VFD) system for surveillance applications in fire and security industries. The system consists of three modules: pixel-level processing to identify potential fire blobs, blob-based spatial-temporal feature extraction, and a Support Vector Machine (SVM) classifier. The proposed novel spatial-temporal features include a spatial-temporal structural feature and a...
Feature description and matching is a fundamental problem for many computer vision applications. However, most existing descriptors only work well on images of a single modality with similar texture. This paper presents a novel basic descriptor unit called a Gixel, which uses an additive scoring method to sample surrounding edge information. Several Gixels in a circular array create a powerful descriptor...
Pose estimation of mobile devices is useful for a wide variety of applications, including augmented reality and geo-tagging. Even though most of today's cell phones are equipped with sensors such as GPS, accelerometers, and gyros, the pose estimated via these is often inaccurate, particularly in urban environments. In this paper, we describe an image based localization algorithm for estimating the...
We study the use of domain adaptation and transfer learning techniques as part of a framework for adaptive object detection. Unlike recent applications of domain adaptation work in computer vision, which generally focus on image classification, we explore the problem of extreme class imbalance present when performing domain adaptation for object detection. The main difficulty caused by this imbalance...
Object detection is an important and challenging problem in the field of computer vision. Classical object detection approaches such as background subtraction and saliency detection do not require manual collection of training samples, but can be easily affected by noise factors, such as luminance changes and cluttered background. On the other hand, supervised learning based approaches such as Boosting...
The outreach of computer vision to non-traditional areas has enormous potential to enable new ways of solving real world problems. One such problem is how to incorporate technology in the effort to protect endangered and threatened species in the wild. This paper presents a snapshot of our interdisciplinary team's ongoing work in the Mojave Desert to build vision tools for field biologists to study...
Conventional methods of gait analysis for person identification use features extracted from a sequence of camera images taken during one or more gait cycles. An implicit assumption is made that the walking direction does not change. However, cameras deployed in real-world environments (and often placed at corners) capture images of humans who walk on paths that, for a variety of reasons, such as turning...
This paper presents a wildfire smoke detection method based on a spatiotemporal bag-of-features (BoF) and a random forest classifier. First, candidate blocks are detected using key-frame differences and non-parametric color models to reduce the computation time. Subsequently, spatiotemporal three-dimensional (3D) volumes are built by combining the candidate blocks in the current key-frame and the...
We present HotSpotter, a fast, accurate algorithm for identifying individual animals against a labeled database. It is not species specific and has been applied to Grevy's and plains zebras, giraffes, leopards, and lionfish. We describe two approaches, both based on extracting and matching keypoints or “hotspots”. The first tests each new query image sequentially against each database image, generating...
The pollen grains of different plant taxa exhibit various shapes and sizes. This structural diversity has made the identification and classification of pollen grains an important tool in many fields. Despite the myriad of applications, the classification of pollen grains is still a tedious and time-consuming process that must be performed by highly skilled specialists. In this paper, we propose an...
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