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In this paper, we study the problem of reproducing the light from a single image of an object covered with random specular microfacets on the surface. We show that such reflectors can be interpreted as a randomized mapping from the lighting to the image. Such specular objects have very different optical properties from both diffuse surfaces and smooth specular objects like metals, so we design a special...
Linear transformations are widely used in the color science. Linear transformation can not ideally map the source and destination color matching functions and this issue induces some errors in the process of conversion. This error is usually deemed negligible for a noise-free system. However, in practice, imaging devices, displays, and printers employ linear transformations to move between color spaces...
RGB-D cameras have enabled real-time 3D video processing for numerous computer vision applications, especially for surveillance type applications. In this paper, we first present a real-time anti-forensic 3D object stream manipulation framework to capture and manipulate live RBG-D data streams to create realistic images/videos showing individuals performing activities they did not actually do. The...
Accurate and consistent ego motion estimation is a critical component of autonomous navigation. For this task, the combination of visual and inertial sensors is an inexpensive, compact, and complementary hardware suite that can be used on many types of vehicles. In this work, we compare two modern approaches to ego motion estimation: the Multi-State Constraint Kalman Filter (MSCKF) and the Sliding...
The gradient orientation pattern matching technique (GOPM) is a block matching technique based on gradient orientations. In this paper, we evaluate this method for stereo matching applications under various conditions that include irregular lighting, occlusion, image blurring, and noise. The performance of the GOPM is compared with that of the standard block matching technique with the sum-of-absolute...
In this paper we describe the space grade camera we developed for the Polarimetric and Helioseismic Imager (PHI) instrument of the Solar Orbiter (SO) mission. The camera, called Correlation Tracking Camera (CTC) will be part of the Image Stabilization System (ISS) used to compensate the spacecraft jitter. Since the ISS works on a correlator basis, the CTC requires a high frame rate while keeping the...
In this research, we focus low illumination video image of "below 1 lux" obtained by normal type video camera, and we consider the method of image correction for moving-object detection by inter-frame differencing. The method of this research is the combination of gamma correction and denoising as the preparation of inter-frame differencing. By such method, the moving-object detection which...
Modern autofocus systems are known for their fast response speed and optimized routines of the image processing. Nevertheless, the bottleneck of the autofocus system development is the transformation of the technical specification into the design rules that strictly take in account the specifications and introduce a guarantee of the best performance. In this paper we propose a new approach in autofocus...
This paper proposes a novel content removal technique for enhancing the camera identification performance. Here, very low bit rate videos with the overall noise patterns having time varying statistics are considered. First, different two dimensional discrete fractional Fourier transforms with different rotational angles are applied to the overall noise pattern of each frame of each video. Second,...
Distributed processing is a new paradigm to analyse the huge volume of video data in camera networks. This paper addresses the problem of distributed single target tracking considering false positives and missed detections. Target tracking is modelled as a dynamic state estimation problem with nonlinear process and measurement model. We propose to use the sigma point information filters combined with...
Sparse bundle adjustment (SBA) is the state of the art method for simultaneously optimizing a set of camera poses and 3D points. The multibody bundle adjustment optimizes the static scene and the moving rigid object(s). The result is one camera path representing the main camera motion and virtual camera path(s) for each of the independently moving objects in the scene. The bundle adjustment for the...
We propose an algorithm to estimate the “lifetime” of events from retinal cameras, such as a Dynamic Vision Sensor (DVS). Unlike standard CMOS cameras, a DVS only transmits pixel-level brightness changes (“events”) at the time they occur with micro-second resolution. Due to its low latency and sparse output, this sensor is very promising for high-speed mobile robotic applications. We develop an algorithm...
This paper utilizes system observability to guide monocular SLAM. Instead of providing all measured features then performing data-driven outlier rejection (such as with RANSAC), we propose to identify only the minimal subset of features which form an optimally observable SLAM subsystem for localization. Modeling the SLAM system as a discrete time system with piece-wise linear SE〈3〉 motion, complete...
Calibrating the response function of a line scanner is very important in many fields of computer vision. We propose a method to reduce nonequivalence present in response functions of pixels. Contrary to current state-of-the-art methods our method uses a linear light source which is usually attached to line scanners for pixel-wise calibration. We define a radiant intensity function for a linear light...
We analyze the observability of 3-D pose from the fusion of visual and inertial sensors. Because the model contains unknown parameters, such as sensor biases, the problem is usually cast as a mixed filtering/identification, with the resulting observability analysis providing necessary conditions for convergence to a unique point estimate. Most models treat sensor bias rates as “noise,” independent...
Estimating the ground plane is often one of the first steps in geometric reasoning processes as it offers easily accessible context knowledge. Especially unconstrained platforms that capture video from egocentric viewpoints can benefit from such knowledge in various ways. A key requirement here is keeping orientation, which can be greatly achieved by keeping track of the ground. We present an approach...
We present an autonomous quadrotor system that is able to perform high precision landing on small platform in both indoor and outdoor environment. Its taking off and landing processes are fully autonomous. We use vision sensor to detect the landing platform, and the vision measurement is enhanced by IMU with SRUKF based sensor fusion method. All computation are done real-time and on-board. We implement...
In an asteroid exploration and sample return mission, accurate estimation of the shape and motion of the target asteroid is essential for selecting a touchdown site and navigating a spacecraft during touchdown operation. In this work, we present an automatic estimation method for the shape and motion of an asteroid, which is planned to be tested in future exploration missions including Japanese Hayabusa-2...
Bundle Adjustment is the current state of the art method for solving the simultaneous localization and mapping problem. This problem is important for the localization of robots, and most acute for flying robots that cannot rely on ground odometry. The solution requires additional information to resolve scale, and most implementations either assume that relatively accurate pose information exists,...
Psoriasis Area and Severity Index, or PASI score [7] is one of the most prevalent scoring indices for Psoriasis. Erythema or redness of skin is an important identifier for evaluation of PASI score. Extra subjectiveness in the evaluation of erythema has been observed, since the perception of redness can be influenced by the skin tone, ambient lighting and many other such factors which are difficult...
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