nils-herrmann/clean_scirepeval huggingface dataset:
Is There a Procedural Logic to Architecture?

Urban models are key to navigation, architecture and entertainment. Apart from visualizing facades, a number of tedious tasks remain largely manual (e.g. compression, generating new facade designs and structurally comparing facades for classification, retrieval and clustering). We propose a novel procedural modelling method to automatically learn a grammar from a set of facades, generate new facade instances and compare facades. To deal with the difficulty of grammatical inference, we reformulate the problem. Instead of inferring a compromising, one-size-fits-all, single grammar for all tasks, we infer a model whose successive refinements are production rules tailored for each task. We demonstrate our automatic rule inference on datasets of two different architectural styles. Our method supercedes manual expert work and cuts the time required to build a procedural model of a facade from several days to a few milliseconds.
Feature-centric Efficient Subwindow Search

Many object detection systems rely on linear classifiers embedded in a sliding-window scheme. Such exhaustive search involves massive computation. Efficient Subwindow Search (ESS)  avoids this by means of branch and bound. However, ESS makes an unfavourable memory tradeoff. Memory usage scales with both image size and overall object model size. This risks becoming prohibitive in a multiclass system. In this paper, we make the connection between sliding-window and Hough-based object detection explicit. Then, we show that the feature-centric view of the latter also nicely fits with the branch and bound paradigm, while it avoids the ESS memory tradeoff. Moreover, on-line integral image calculations are not needed. Both theoretical and quantitative comparisons with the ESS bound are provided, showing that none of this comes at the expense of performance.
Body Parts Dependent Joint Regressors for Human Pose Estimation in Still Images

In this work, we address the problem of estimating 2d human pose from still images. Articulated body pose estimation is challenging due to the large variation in body poses and appearances of the different body parts. Recent methods that rely on the pictorial structure framework have shown to be very successful in solving this task. They model the body part appearances using discriminatively trained, independent part templates and the spatial relations of the body parts using a tree model. Within such a framework, we address the problem of obtaining better part templates which are able to handle a very high variation in appearance. To this end, we introduce parts dependent body joint regressors which are random forests that operate over two layers. While the first layer acts as an independent body part classifier, the second layer takes the estimated class distributions of the first one into account and is thereby able to predict joint locations by modeling the interdependence and co-occurrence of the parts. This helps to overcome typical ambiguities of tree structures, such as self-similarities of legs and arms. In addition, we introduce a novel data set termed FashionPose that contains over 7,000 images with a challenging variation of body part appearances due to a large variation of dressing styles. In the experiments, we demonstrate that the proposed parts dependent joint regressors outperform independent classifiers or regressors. The method also performs better or similar to the state-of-the-art in terms of accuracy, while running with a couple of frames per second.
Iterative Nearest Neighbors for classification and dimensionality reduction

Representative data in terms of a set of selected samples is of interest for various machine learning applications, e.g. dimensionality reduction and classification. The best-known techniques probably still are k-Nearest Neighbors (kNN) and its variants. Recently, richer representations have become popular. Examples are methods based on l1-regularized least squares (Sparse Representation (SR)) or l2-regularized least squares (Collaborative Representation (CR)), or on l1-constrained least squares (Local Linear Embedding (LLE)). We propose Iterative Nearest Neighbors (INN). This is a novel sparse representation that combines the power of SR and LLE with the computational simplicity of kNN. We test our method in terms of dimensionality reduction and classification, using standard benchmarks such as faces (AR), traffic signs (GTSRB), and PASCAL VOC 2007. INN performs better than NN and comparable with CR and SR, while being orders of magnitude faster than the latter.
Drift detection and removal for sequential structure from motion algorithms

In sequential Structure from Motion algorithms for extended image or video sequences, error build up caused by drift poses a problem as feature tracks that normally represent a single scene point will have distinct 3D reconstructions. For the final bundle adjustment to remove this drift, it must be told about these 3D-3D correspondences through a change in the cost function. However, as a bundle adjustment is a nonlinear optimization technique, the drift needs to be removed from the supplied initial solution to allow for convergence of the bundle adjustment to the real global optimum. Before drift can be removed, it has to be detected. This is accomplished through understanding of the long term behavior of drift which leaves 3D reconstructions from short sequences intact. Drift detection boils down to identifying reconstructions of the same scene part that only differ up to a projective transformation. After detection, the drift can be removed from future processed images and an Adapted Bundle Adjustment using correspondences supplied by the drift detection can remove the drift from previous images. Several experiments on real video sequences demonstrate the merit of drift detection and removal.
Autonomous grouping of contour-segments using an adaptive region-growing algorithm

We propose a new method to automatically group edge-segments (extracted from an image) into a fully connected line-drawing. Unlike some other methods, this algorithm does not assume that the result is topologically simple (i.e. composed of simple closed curves) but is able to recover more complicated, and therefore salient, topological features such as T-junctions. The method is based on a region-growing algorithm which uses stochastically obtained geometric information to halt the region expansion.
Joint Tracking and Ground Plane Estimation

We propose a novel framework that jointly estimates the ground plane and a target's motion trajectory. This results in improvements for both. Estimating their joint posterior is based on Particle Markov Chain Monte Carlo (Particle MCMC). In Particle MCMC, the best target state is inferred by a particle filter and the best ground plane is obtained by MCMC. Compared with conventional sampling methods that iteratively infer the best target states and ground plane parameters, our method infers them jointly. This reduces sampling errors drastically. Experimental results demonstrate that our method outperforms several state-of-the-art tracking methods, while the ground plane accuracy is also improved.
Anchored Neighborhood Regression for Fast Example-Based Super-Resolution

Recently there have been significant advances in image up scaling or image super-resolution based on a dictionary of low and high resolution exemplars. The running time of the methods is often ignored despite the fact that it is a critical factor for real applications. This paper proposes fast super-resolution methods while making no compromise on quality. First, we support the use of sparse learned dictionaries in combination with neighbor embedding methods. In this case, the nearest neighbors are computed using the correlation with the dictionary atoms rather than the Euclidean distance. Moreover, we show that most of the current approaches reach top performance for the right parameters. Second, we show that using global collaborative coding has considerable speed advantages, reducing the super-resolution mapping to a precomputed projective matrix. Third, we propose the anchored neighborhood regression. That is to anchor the neighborhood embedding of a low resolution patch to the nearest atom in the dictionary and to precompute the corresponding embedding matrix. These proposals are contrasted with current state-of-the-art methods on standard images. We obtain similar or improved quality and one or two orders of magnitude speed improvements.
Wide-baseline stereo from multiple views: A probabilistic account

This paper describes a method for dense depth reconstruction from a small set of wide-baseline images. In a wide-baseline setting an inherent difficulty which complicates the stereo-correspondence problem is self-occlusion. Also, we have to consider the possibility that image pixels in different images, which are projections of the same point in the scene, will have different color values due to non-Lambertian effects or discretization errors. We propose a Bayesian approach to tackle these problems. In this framework, the images are regarded as noisy measurements of an underlying 'true' image-function. Also, the image data is considered incomplete, in the sense that we do not know which pixels from a particular image are occluded in the other images. We describe an EM-algorithm, which iterates between estimating values for all hidden quantities, and optimizing the current depth estimates. The algorithm has few free parameters, displays a stable convergence behavior and generates accurate depth estimates. The approach is illustrated with several challenging real-world examples. We also show how the algorithm can generate realistic view interpolations and how it merges the information of all images into a new, synthetic view.
Real-time 3D hand gesture interaction with a robot for understanding directions from humans

This paper implements a real-time hand gesture recognition algorithm based on the inexpensive Kinect sensor. The use of a depth sensor allows for complex 3D gestures where the system is robust to disturbing objects or persons in the background. A Haarlet-based hand gesture recognition system is implemented to detect hand gestures in any orientation, and more in particular pointing gestures while extracting the 3D pointing direction. The system is integrated on an interactive robot (based on ROS), allowing for real-time hand gesture interaction with the robot. Pointing gestures are translated into goals for the robot, telling him where to go. A demo scenario is presented where the robot looks for persons to interact with, asks for directions, and then detects a 3D pointing direction. The robot then explores his vicinity in the given direction and looks for a new person to interact with.
I know what you did last summer: object-level auto-annotation of holiday snaps

The state-of-the art in visual object retrieval from large databases allows to search millions of images on the object level. Recently, complementary works have proposed systems to crawl large object databases from community photo collections on the Internet. We combine these two lines of work to a large-scale system for auto-annotation of holiday snaps. The resulting method allows for automatic labeling objects such as landmark buildings, scenes, pieces of art etc. at the object level in a fully automatic manner. The labeling is multi-modal and consists of textual tags, geographic location, and related content on the Internet. Furthermore, the efficiency of the retrieval process is optimized by creating more compact and precise indices for visual vocabularies using background information obtained in the crawling stage of the system. We demonstrate the scalability and precision of the proposed method by conducting experiments on millions of images downloaded from community photo collections on the Internet.
Real-time facial feature detection using conditional regression forests

Although facial feature detection from 2D images is a well-studied field, there is a lack of real-time methods that estimate feature points even on low quality images. Here we propose conditional regression forest for this task. While regression forest learn the relations between facial image patches and the location of feature points from the entire set of faces, conditional regression forest learn the relations conditional to global face properties. In our experiments, we use the head pose as a global property and demonstrate that conditional regression forests outperform regression forests for facial feature detection. We have evaluated the method on the challenging Labeled Faces in the Wild [20] database where close-to-human accuracy is achieved while processing images in real-time.
Partial surface integration based on variational implicit functions and surfaces for 3D model building

Most three-dimensional acquisition systems generate several partial reconstructions that have to be registered and integrated for building a complete 3D model. In this paper, we propose a volumetric shape integration method, consisting of weighted signed distance functions represented as variational implicit functions (VIF) or surfaces (VIS). Texture integration is solved similarly by using three weighted color junctions also based on VIFs. Using these continuous (not grid-based) representations solves current limitations of volumetric methods: no memory inefficient and resolution limiting grid representation is required. The built-in smoothing properties of the VIS representations also improve the robustness of the final integration against noise in the input data. Experimental results are performed on real-live, noiseless and noisy synthetic data of human faces in order to show the robustness and accuracy of the integration algorithm.
Learning to Predict Sequences of Human Visual Fixations

Most state-of-the-art visual attention models estimate the probability distribution of fixating the eyes in a location of the image, the so-called saliency maps. Yet, these models do not predict the temporal sequence of eye fixations, which may be valuable for better predicting the human eye fixations, as well as for understanding the role of the different cues during visual exploration. In this paper, we present a method for predicting the sequence of human eye fixations, which is learned from the recorded human eye-tracking data. We use least-squares policy iteration (LSPI) to learn a visual exploration policy that mimics the recorded eye-fixation examples. The model uses a different set of parameters for the different stages of visual exploration that capture the importance of the cues during the scanpath. In a series of experiments, we demonstrate the effectiveness of using LSPI for combining multiple cues at different stages of the scanpath. The learned parameters suggest that the low-level and high-level cues (semantics) are similarly important at the first eye fixation of the scanpath, and the contribution of high-level cues keeps increasing during the visual exploration. Results show that our approach obtains the state-of-the-art performances on two challenging data sets: 1) OSIE data set and 2) MIT data set.
Scene Cut: Class-Specific Object Detection and Segmentation in 3D Scenes

In this paper we present a method to combine the detection and segmentation of object categories from 3D scenes. In the process, we combine the top-down cues available from object detection technique of Implicit Shape Models and the bottom-up power of Markov Random Fields for the purpose of segmentation. While such approaches have been tried for the 2D image problem domain before, this is the first application of such a method in 3D. 3D scene understanding is prone to many problems different from 2D owing to problems from noise, lack of distinctive high-frequency feature information, mesh parametrization problems etc. Our method enables us to localize objects of interest for more purposeful meshing and subsequent scene understanding.
Texture inspection with self-adaptive convolution filters

A resolution-independent method for detection of imperfections in quasi-periodic textures is described. After image standardization, the period is estimated in the horizontal and vertical directions. This determines the size of a sparse convolution mask. Mask coefficients are determined by the well-known technique of eigenfilter extraction. The method thus offers a completely automated generation of a bank of suitable filters, the form and the coefficients of which are made dependent on the texture type to be inspected. After feature extraction in the filtered images, a Mahalanobis classifier is applied.<<ETX>>
Coupled Detection and Trajectory Estimation for Multi-Object Tracking

We present a novel approach for multi-object tracking which considers object detection and spacetime trajectory estimation as a coupled optimization problem. It is formulated in a hypothesis selection framework and builds upon a state-of-the-art pedestrian detector. At each time instant, it searches for the globally optimal set of spacetime trajectories which provides the best explanation for the current image and for all evidence collected so far, while satisfying the constraints that no two objects may occupy the same physical space, nor explain the same image pixels at any point in time. Successful trajectory hypotheses are fed back to guide object detection in future frames. The optimization procedure is kept efficient through incremental computation and conservative hypothesis pruning. The resulting approach can initialize automatically and track a large and varying number of persons over long periods and through complex scenes with clutter, occlusions, and large-scale background changes. Also, the global optimization framework allows our system to recover from mismatches and temporarily lost tracks. We demonstrate the feasibility of the proposed approach on several challenging video sequences.
Robust tracking-by-detection using a detector confidence particle filter

We propose a novel approach for multi-person tracking-by-detection in a particle filtering framework. In addition to final high-confidence detections, our algorithm uses the continuous confidence of pedestrian detectors and online trained, instance-specific classifiers as a graded observation model. Thus, generic object category knowledge is complemented by instance-specific information. A main contribution of this paper is the exploration of how these unreliable information sources can be used for multi-person tracking. The resulting algorithm robustly tracks a large number of dynamically moving persons in complex scenes with occlusions, does not rely on background modeling, and operates entirely in 2D (requiring no camera or ground plane calibration). Our Markovian approach relies only on information from the past and is suitable for online applications. We evaluate the performance on a variety of datasets and show that it improves upon state-of-the-art methods.
Multibody Structure-from-Motion in Practice

Multibody structure from motion (SfM) is the extension of classical SfM to dynamic scenes with multiple rigidly moving objects. Recent research has unveiled some of the mathematical foundations of the problem, but a practical algorithm which can handle realistic sequences is still missing. In this paper, we discuss the requirements for such an algorithm, highlight theoretical issues and practical problems, and describe how a static structure-from-motion framework needs to be extended to handle real dynamic scenes. Theoretical issues include different situations in which the number of independently moving scene objects changes: Moving objects can enter or leave the field of view, merge into the static background (e.g., when a car is parked), or split off from the background and start moving independently. Practical issues arise due to small freely moving foreground objects with few and short feature tracks. We argue that all of these difficulties need to be handled online as structure-from-motion estimation progresses, and present an exemplary solution using the framework of probabilistic model-scoring.
Haarlet-based hand gesture recognition for 3D interaction

This paper presents a system to manipulate 3D objects or navigate through 3D models by detecting the gestures and the movements of the hands of a user in front of a camera mounted on top of a screen. This paper more particularly introduces an improved skin color segmentation algorithm which combines an online and an offline model; and a Haarlet-based hand gesture recognition system, where the Haarlets are trained based on Average Neighborhood Margin Maximization (ANMM). The result is a real-time marker-less interaction system which is applied to two applications, one for manipulating 3D objects, and the other for navigating through a 3D model.
Probabilistic object tracking using multiple features

We present a generic tracker which can handle a variety of different objects. For this purpose, groups of low-level features like interest points, edges, homogeneous and textured regions, are combined on a flexible and opportunistic basis. They sufficiently characterize an object and allow robust tracking as they are complementary sources of information which describe both the shape and the appearance of an object. These low-level features are integrated into a particle filter framework as this has proven very successful for non-linear and non-Gaussian estimation problems. We concentrate on rigid objects under affine transformations. Results on real-world scenes demonstrate the performance of the proposed tracker.
Deep Features or Not: Temperature and Time Prediction in Outdoor Scenes

In this paper, we study the effectiveness of features from Convolutional Neural Networks (CNN) for predicting the ambient temperature as well as the time of the year in an outdoor scene. We follow the benchmark provided by Glasner et al.  one of whose findings was that simple handcrafted features are better than the deep features (from fully connected layers) for temperature prediction. As in their work, we use the VGG-16 architecture for our CNNs, pretrained for classification on ImageNet. Our main findings on the temperature prediction task are as follows. (i) The pooling layers provide better features than the fully connected layers. (ii) The quality of the features improves little with fine-tuning of the CNN on training data. (iii) Our best setup significantly improves over the results from Glasner et al. showing that the deep features are successful in turning a camera into a crude temperature sensor. Moreover, we validate our findings also for time prediction and achieve accurate season, month, week, time of the day, and hour prediction.
Efficient Non-Maximum Suppression

In this work we scrutinize a low level computer vision task - non-maximum suppression (NMS) - which is a crucial preprocessing step in many computer vision applications. Especially in real time scenarios, efficient algorithms for such preprocessing algorithms, which operate on the full image resolution, are important. In the case of NMS, it seems that merely the straightforward implementation or slight improvements are known. We show that these are far from being optimal, and derive several algorithms ranging from easy-to-implement to highly-efficient