Siamak Khatibi

Siamak Khatibi
Blekinge Institute of Technology | BTH · DEPARTMENT OF TECHNOLOGY AND AESTHETICS (DITE)

PhD

About

67
Publications
8,531
Reads
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405
Citations
Introduction
Siamak Khatibi currently works at the DEPARTMENT OF TECHNOLOGY AND AESTHETICS (DITE), Blekinge Institute of Technology. His research team is conducting leading-edge research in advanced computer vision with special focus on 3D reconstruction and image/video-based scene understanding. His team has been developing novel reconstruction methods for a variety of data types from singular single image data to spatial-temporal big data resources. The research of the team has led to several innovations for industrial applications. Semantic content awareness of streaming data and implementing bio-inspired methodologies have been other research areas. These ideas have been implemented in many applications for detection, classification, analysis and defining new image/video quality metrics.
Additional affiliations
January 2017 - August 2017
Blekinge Institute of Technology
Position
  • Professor (Associate)
June 2007 - present
Blekinge Institute of Technology
Position
  • Professor (Associate)
June 2007 - present
Blekinge Institute of Technology
Position
  • Professor (Associate)

Publications

Publications (67)
Article
Full-text available
In order to further improve positioning accuracy, this paper proposes an indoor vision/INS integrated mobile robot navigation method using multimodel-based multifrequency Kalman filter. Firstly, to overcome the insufficient accuracy of visual data when a robot turns, a novel multimodel integrated scheme has been investigated for the mobile robots w...
Article
Full-text available
The study of the evolution process of our visual system indicates the existence of variational spatial arrangement; from densely hexagonal in the fovea to a sparse circular structure in the peripheral retina. Today’s sensor spatial arrangement is inspired by our visual system. However, we have not come further than rigid rectangular and, on a minor...
Article
Full-text available
Our vision system has a combination of different sensor arrangements from hexagonal to elliptical ones. Inspired from this variation in type of arrangements we propose a general framework by which it becomes feasible to create virtual deformable sensor arrangements. In the framework for a certain sensor arrangement a configuration of three optional...
Article
Full-text available
The arrangement and form of the image sensor have a fundamental effect on any further image processing operation and image visualization. In this paper, we present a software-based method to change the arrangement and form of pixel sensors that generate hexagonal pixel forms on a hexagonal grid. We evaluate four different image sensor forms and str...
Chapter
The quality assessment of a high dynamic image is a challenging task. The few available no reference image quality methods for high dynamic range images are generally in evaluation stage. The most available image quality assessment methods are designed to assess low dynamic range images. In the paper, we show the assessment of high dynamic range im...
Article
Full-text available
The study of the evolution process of our visual system indicates the existence of variational spatial arrangement; from densely hexagonal in the fovea to a sparse circular structure in the peripheral retina. [...]
Article
Full-text available
Achieving a high fill factor is a bottleneck problem for capturing high-quality images. There are hardware and software solutions to overcome this problem. In the solutions, the fill factor is known. However, this is an industrial secrecy by most image sensor manufacturers due to its direct effect on the assessment of the sensor quality. In this pa...
Article
Full-text available
The current camera has made a huge progress in the sensor resolution and the lowluminance performance. However, we are still far from having an optimal camera as powerful as our eye is. The study of the evolution process of our visual system indicates attention to two major issues: the form and the density of the sensor. High contrast and optimal s...
Conference Paper
Full-text available
As one of important outcomes of the past decades of researches on sensor arrays for digital cameras, the manufacturers of sensor array technology have responded to the necessity and importance of obtaining an optimal fill factor, which has great impact on collection of incident photons on the sensor, with hardware solution e.g. by introducing micro...
Conference Paper
Full-text available
Depth perception is one of important abilities of the human visual system to perceive the three dimensional world. Shadow technique that offers different depth information from different viewing points, known as Da Vinci stereopsis, has been used in classical paintings. In this paper, we report a method towards measuring the relative depth informat...
Conference Paper
Full-text available
In the past twenty years, CCD sensor has made huge progress in improving resolution and low-light performance by hardware. However due to physical limits of the sensor design and fabrication, fill factor has become the bottle neck for improving quantum efficiency of CCD sensor to widen dynamic range of images. In this paper we propose a novel softw...
Conference Paper
Full-text available
A novel region based 3D semantic mapping method is proposed for urban scenes. The proposed Semantic Urban Maps (SUM) method labels the regions of segmented images into a set of geometric and semantic classes simultaneously by employing a Markov Random Field based classification framework. The pixels in the labeled images are back-projected into a s...
Article
Every urban environment contains a rich set of dominant surfaces which can provide a solid foundation for visual odometry estimation. A visual odometry estimation method is proposed which robustly computes the motion of a moving vehicle from a stereo vision camera. The proposed method first identifies the candidate planar region in the stereo image...
Conference Paper
Full-text available
Popularity of the streaming media content such as videos can be ascribed to the perceptual quality, to some extent, of the content. The traditional methods of audio/video quality assessment lack in provision of the input from higher cognitive of the human perception. Some studies have revealed that liking or disliking of a certain content can bias...
Article
Full-text available
The problem of robust extraction of visual odometry from a sequence of images obtained by an eye in hand camera configuration is addressed. A novel approach toward solving planar template based tracking is proposed which performs a non-linear image alignment for successful retrieval of camera transformations. In order to obtain global optimum a bio...
Conference Paper
Full-text available
The problem of robust extraction of ego-motion from a sequence of images for an eye-in-hand camera configuration is addressed. A novel approach toward solving planar template based tracking is proposed which performs a non-linear image alignment and a planar similarity optimization to recover camera transformations from planar regions of a scene. T...
Conference Paper
Full-text available
The problem of robust and invariant representation of places is being addressed. A place recognition technique is proposed followed by an application to a semantic topological mapping. The proposed technique is evaluated on a robot localization database which consists of a large set of images taken under various weather conditions. The results show...
Conference Paper
Full-text available
Most of the computer vision algorithms operate pixel-wise and process image in a small neighborhood for feature extraction. Such a feature extraction strategy ignores the context of an object in the real world. Taking geometric context into account while classifying various regions in a scene, we can discriminate the similar features obtained from...
Conference Paper
Full-text available
The cumbersome process of construction and incremental update of large indoor maps can be simplified by semantic maps. A novel semantic mapping method for indoor environments is proposed which employs a flash-n-extend strategy for constructing and updating the map. At the exposure of every flash event, a 3D snapshot of the environment is taken whic...
Conference Paper
Full-text available
Triangulation technique is one of the most commonly techniques used in three dimensional measurements. Depth reconstruction accuracy is a direct impact of the quantization process and this is related to the number of pixels of the sensor. Dithering technique (DT) benefits from relative fine movement between object and sensor to reduce the quantizat...
Article
This paper presents a novel approach for the classification of planar surfaces in an unorganized point clouds. A feature-based planner surface detection method is proposed which classifies a point cloud data into planar and non-planar points by learning a classification model from an example set of planes. The algorithm performs segmentation of the...
Article
Full-text available
Abstract- Triangulation technique is one of the most commonly techniques used in three dimensional measurements. Hardware and software used in 3D scanning systems are main error sources affected the accuracy of scanners. Depth reconstruction accuracy is a direct impact of the quantization process, and so it is related to the pixel size of the senso...
Conference Paper
Full-text available
Consumer market is recently experiencing 3D display. To prepare the market for new era of 3D TV, the 3D display popularity can be increased by making ease of capturing or generating of stereo information. The results of recent research on 3D structure modeling from single images can be used to generate stereo images. We evaluate some of typical 3D...
Conference Paper
Full-text available
In this paper, we present several fusion approaches to merge speed limits reported in digital maps with detected speed limit signs using an onboard camera. Digital maps holding speed limits signs are required to be updated to cover speed limit changes and are unable to support variable speed limits. On the other hand, a camera system placed onboard...
Article
The depth spatial quantization uncertainty is one of the factors which influence the depth reconstruction accuracy caused by a discrete sensor. This paper discusses the quantization uncertainty distribution, introduces a mathematical model of the uncertainty interval range, and analyzes the movements of the sensors in an Intelligent Vision Agent Sy...
Code
Full-text available
How we use Matlab in Computer Vision problems is mostly depend on the problems. To demonstrate some of Matlab functionalities in this area, some examples and their related codes are presented.
Article
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Parallel stereo vision is a general method to measure a 3D target position. In order to increase the common field of view (FoV), it is popular to apply a stereo vision setup with a non-zero convergence angle and then using a rectification procedure for the sake of efficiency when calculating the target position. Unfortunately, the homographies caus...
Chapter
Full-text available
The chapter focuses on depth reconstruction, the arrangement of multiple stereo sensors for human activities space, which are important issues of IVAS. The research work can be concluded by means of two terms: the uncertainty analysis and human factor handling for vision system. The analysis presented shows that the quantized depth reconstruction a...
Article
Full-text available
The Intelligent Vision Agent System, IVAS, is a system for automatic target detection, identification and information processing for use in human activities surveillance. This system consists of multiple sensors, and with control of their deployment and autonomous servo. Finding the optimal configuration for these sensors in order to capture the ta...
Conference Paper
Full-text available
This paper presents a method for planning the position of multiple stereo sensors in an indoor environment. This is a component in an intelligent vision agent system. We propose a new approach to dynamically adjust the multiple stereo pair's position, pose and baseline length in 3D space in order to get sufficient visibility and enough accuracy for...
Article
Acute exposure to 100 mM isotonic ethanol (EtOH) increased intracellular Ca2+ concentration ([Ca2+]i), induced cell swelling, and transformed actin cytoskeleton in astroglial primary cultures from rat cerebral cortex. Fluorometric recordings of fluo-3AM- or fura-2AM-incubated astroglial cells revealed that EtOH induced [Ca2+]i transients in a small...
Article
Acute exposure to 100 mm isotonic ethanol (EtOH) increased intracellular Ca2+ concentration ([Ca2+]i), induced cell swelling, and transformed actin cytoskeleton in astroglial primary cultures from rat cerebral cortex. Fluorometric recordings of fluo-3AM- or fura-2AM-incubated astroglial cells revealed that EtOH induced [Ca2+]i transients in a small...
Article
Astrocytes, which constitute a prominent part of the number and volume of brain cells, have a high capacity for controlling their volume, and astrocytic swelling is associated with a number of pathological states affecting the CNS. In order to understand the mechanisms for regulating cell volume in astrocytes better, it is of utmost importance to d...
Article
Full-text available
Cell volume changes are often associated with important physiological and pathological processes in the cell. These changes may be the means by which the cell interacts with its surrounding. Astroglial cells change their volume and shape under several circumstances that affect the central nervous system. Following an incidence of brain damage, such...
Article
We have studied three-dimensional reconstruction methods to estimate the cell volume of astroglial cells in primary culture. The studies are based on fluorescence imaging and optical sectioning. An automated image-acquisition system was developed to collect two-dimensional microscopic images. Images were reconstructed by the Linear Maximum a Poster...
Article
The effects of 5-hydroxytryptamine or glutamate treatment on mechanically induced intercellular calcium waves were studied in gap junction-coupled astroglial cells using rat astroglial-neuronal primary cultures from hippocampus. Imaging software was developed to study amplitude, velocity and extent of wave propagation. Velocity software was designe...
Article
Full-text available
An automated fluorescence microscopy imaging and image analysis system was developed for studying the characteristics of intra- and intercellular calcium signaling. The image analysis techniques were based on fluorescence wide-field microscopy images and motion analysis. The system was used for the study of cell state and spatial propagation of cal...
Article
Full-text available
We describe two new automatic image processing techniques for the study of cell state and spatial propagation of calcium waves in cultured astroglial cells. These techniques are based on fluorescent microscopy images combined with algorithms developed for image segmentation, intensity analyses of fluorescent images and image motion. In cell state s...
Article
Full-text available
Wide-field fluorescence microscopy in conjunction with advanced image analysis procedures offers new and exciting possibilities for studying the dynamic activity at the cellular level. More specifically, we have developed a novel imaging and image analysis technique for investigating the transduction mechanisms behind astroglial cell swelling. By o...
Article
The effects of different adrenoceptor agonists were investigated on mechanically induced Ca2+ waves in astroglial cells in astroglial–neuronal mixed cultures from rat hippocampus. In the initial part of the study some properties of the waves were characterized. The results show that the initiation of the Ca2+ waves was not critically dependent on e...
Article
Glutamate (Glu) plays an important role in the early development of brain injuries caused by ischemia, i.e. stroke, or brain trauma. Glu induces a rapid astroglial swelling which, in turn, deranges the composition of neuroactive substances in the extracellular space. We report that Glu can induce astroglial cell swelling by interaction with metabot...

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