Improved Depth Map Estimation from Stereo Images based on Hybrid Method

In this paper, a stereo matching algorithm based on image segments is presented. We propose the hybrid segmentation algorithm that is based on a combination of the Belief Propagation and Mean Shift algorithms with aim to refine the disparity and depth map by using a stereo pair of images. This algorithm utilizes image filtering and modified SAD (Sum of Absolute Differences) stereo matching method. Firstly, a color based segmentation method is applied for segmenting the left image of the input stereo pair (reference image) into regions. The aim of the segmentation is to simplify representation of the image into the form that is easier to analyze and is able to locate objects in images. Secondly, results of the segmentation are used as an input of the local window-based matching method to determine the disparity estimate of each image pixel. The obtained experimental results demonstrate that the final depth map can be obtained by application of segment disparities to the original images. Experimental results with the stereo testing images show that our proposed Hybrid algorithm HSAD gives a good performance

Intelligent manipulation technique for multi-branch robotic systems

New analytical development in kinematics planning is reported. The INtelligent KInematics Planner (INKIP) consists of the kinematics spline theory and the adaptive logic annealing process. Also, a novel framework of robot learning mechanism is introduced. The FUzzy LOgic Self Organized Neural Networks (FULOSONN) integrates fuzzy logic in commands, control, searching, and reasoning, the embedded expert system for nominal robotics knowledge implementation, and the self organized neural networks for the dynamic knowledge evolutionary process. Progress on the mechanical construction of SRA Advanced Robotic System (SRAARS) and the real time robot vision system is also reported. A decision was made to incorporate the Local Area Network (LAN) technology in the overall communication system

Advances in Stereo Vision

Stereopsis is a vision process whose geometrical foundation has been known for a long time, ever since the experiments by Wheatstone, in the 19th century. Nevertheless, its inner workings in biological organisms, as well as its emulation by computer systems, have proven elusive, and stereo vision remains a very active and challenging area of research nowadays. In this volume we have attempted to present a limited but relevant sample of the work being carried out in stereo vision, covering significant aspects both from the applied and from the theoretical standpoints

Quality assessment for virtual reality technology based on real scene

Virtual reality technology is a new display technology, which provides users with real viewing experience. As known, most of the virtual reality display through stereoscopic images. However, image quality will be influenced by the collection, storage and transmission process. If the stereoscopic image quality in the virtual reality technology is seriously damaged, the user will feel uncomfortable, and this can even cause healthy problems. In this paper, we establish a set of accurate and effective evaluations for the virtual reality. In the preprocessing, we segment the original reference and distorted image into binocular regions and monocular regions. Then, the Information-weighted SSIM (IW-SSIM) or Information-weighted PSNR (IW-PSNR) values over the monocular regions are applied to obtain the IW-score. At the same time, the Stereo-weighted-SSIM (SW-SSIM) or Stereo-weighted-PSNR (SW-PSNR) can be used to calculate the SW-score. Finally, we pool the stereoscopic images score by combing the IW-score and SW-score. Experiments show that our method is very consistent with human subjective judgment standard in the evaluation of virtual reality technology

Selected Problems in Photogrammetric Systems Analysis

Disertační práce se zabývá vybranými partiemi digitální fotogrammetrie. V první části práce je definované téma a popsán současný stav poznání. V následujících kapitolách jsou postupně řešeny čtyři dílčí navzájem navazující cíle. První oblastí je návrh metody pro hledání souhlasných bodů v obraze. Byly navrženy dvě nové metody. První z nich používá konverzi snímků do nepravých barev a druhá využívá pravděpodobností model získaný ze známých párů souhlasných bodů. Druhým tématem je analýza přesnosti výsledné rekonstrukce prostorových bodů. Postupně je analyzován vliv různých faktorů na přesnost rekonstrukce. Stěžejní oblastí je zkoumání vlivu chybného zarovnání kamer a chyby v určení souhlasných bodů. Třetím tématem je tvorba hloubkových map. Byly navrženy dva postupy. První přístup spočívá v kombinaci pasivní a aktivní metody druhý přístup vychází z pasivní metody a využívá spojitosti hloubkové mapy. Poslední zvolenou oblastí zájmu je hodnocení kvality 3D videa. Byly provedeny a statisticky vyhodnoceny subjektvní testy 3D vjemu pro různé zobrazovací systémy v závislosti na úhlu pozorováníThis dissertation deals with selected topics of digital photogrammetry. The problem is defined and the state of the art is described in the first part of the dissertation. Four specified aims are solved. The proposal of the method for finding corresponding points is the first topic. Two new methods were proposed. The first method uses conversion of an image to pseudo- colors. The second method used a probabilistic model obtained from the known pairs of the corresponding points. The analysis of the accuracy of the reconstruction is the second solved topic. The influence of the various aspects to the accuracy of the reconstruction is analyzed. The most attention is paid to incorrect camera alignment and errors in finding corresponding points. The third topic is estimation of the depth maps. The two method were proposed. The first method is based on the combination of the passive and active method. The second wholly passive approach uses continuity of the depth map. The last investigative topic is quality of experience of the 3D videos. The subjective tests of the perception of 3D content for the various 3D displaying systems were performed. The dependency of the perception on the viewing angle was also investigated.

Quality index for stereoscopic images by jointly evaluating cyclopean amplitude and cyclopean phase

With widespread applications of three-dimensional (3-D) technology, measuring quality of experience for 3-D multimedia content plays an increasingly important role. In this paper, we propose a full reference stereo image quality assessment (SIQA) framework which focuses on the innovation of binocular visual properties and applications of low-level features. On one hand, based on the fact that human visual system understands an image mainly according to its low-level features, local phase and local amplitude extracted from phase congruency measurement are employed as primary features. Considering the less prominent performance of amplitude in IQA, visual saliency is applied into the modification on amplitude. On the other hand, by fully considering binocular rivalry phenomena, we create the cyclopean amplitude map and cyclopean phase map. With this method, both image features and binocular visual properties are mutually combined with each other. Meanwhile, a novel binocular modulation function in spatial domain is also adopted into the overall quality prediction of amplitude and phase. Extensive experiments demonstrate that the proposed framework achieves higher consistency with subjective tests than relevant SIQA metrics

Implementing Cepstral Filtering Technique using Gabor Filters

Cepstral filtering technique is applied on an interlaced image, the pattern similar to that which is found in layer IV of Primate Visual Cortex. Unless the signals from left and right eyes are placed simultaneously, the disparity cannot be detected. Therefore, it has a great significance in the sphere of stereo vision. It involves Power spectrum in computation, which is square of absolute of Fast Fourier Transform (FFT), is a complicated and hardware unfriendly. This paper shows the estimation of the Cepstral technique using a set of Gabor filters. The Ocular Dominance Column pattern analysis by the Gabor function is comparable to the perception in the human visual and makes the algorithm closer to biology. We propose an algorithm in which Gabor filters, instead of Power Spectrum, are applied to an interlaced image in the Cepstral algorithm. This scheme makes it hardware friendly as it gives the flexibility of working with modules which can be imitated in hardware. Building a FFT module is a tough task in analog circuit but determining Gabor Energy, an alternative to it, can be achieved by elementary circuits. The Phase, Energy Models and other methods use multi-lambda Gabor filters to compute disparity. The proposed method uses sum of absolute difference to choose a single Gabor filter of appropriate lambda that fits to find the disparity. The algorithm inherits the quality of both Gabor filter and Ocular Dominance Pattern and hence a biologically inspired and suitable for hardware realization. The proposed algorithm has been implemented on the test data image. A hardware scheme has also been proposed that can be used to estimate disparity and the idea can be extended in building complex modules that can perform real time - real image operations with a handful of resources as compared to employing complex digital FPGAs and CPLDs